Which Shower Tile Backer board is best?
When it comes to installing a tile backer board you typically have the following choice:
- difficult to install and cheap
- easy to install and expensive
So which tile backer board should you use in your bathroom?
I’m going to break them down by category and cover the finer points of each. We’ll start with
Sheetrock in a wet area is a major no-no. It usually works fine for a kitchen backsplash or fireplace but as a shower tile backer board, it’s a bad idea and against code.
This also goes for moisture-resistant drywall also known as green board. It’s my understanding that green board isn’t approved for residential wet areas anymore.
If sheetrock (drywall) gets wet it expands and swells and will ruin any tile that you’ve installed on it. There are better options.
Kerdi over drywall backing
It’s not quite as simple when you are installing a product like Schluter’s Kerdi waterproof membrane. Schluter actually recommends sheetrock as a backing.
The thinking is that as long as there’s a completely waterproof membrane on the front of the drywall that the sheetrock will never get wet.
Factor in that drywall is easy to install and easy to thinset over and you can see the appeal of waterproofing your shower this way.
Personally, I don’t like it. If everything goes as planned you shouldn’t have any issues but if you make one mistake then you’ve just compromised your whole shower.
If a pipe or faucet ever leaks in the wall this will ruin your shower. Furthermore, if another trade, such as the shower glass installers, makes a mistake then you’ll be fighting over who pays for what.
Finally, if water wicks past your seams, as some YouTubers claim, it is conceivable that drywall could swell over time.
When I install Kerdi I always use cement board. The cost is not much more and the insurance is worth it to me.
Bottom line: if there’s drywall on your shower walls it better be a Kerdi installation. Otherwise, it’s being done wrong.
My Rating: No. With Kerdi- hmmmm….ok.
Glass Mat Gypsum Wall Board
The most popular product in this category is DensShield tile backer board. This product has basically taken the place of green board mentioned earlier.
It is made of moisture-resistant gypsum but it also has a waterproof coating on its face. Like sheetrock, it’s easy to install and very economical. Because of these things, it is the new favorite of home builders everywhere.
Where they used to use green board back in the 1980’s they now use this new gypsum hybrid.
In tract homes and new construction, it’s generally installed by the sheetrock crew. Generally, the sheetrock crew (and oftentimes the tile installers) don’t know how to properly waterproof the seams, screw holes, and edges.
But it’s cheap and lasts long enough which is music to most tract home builder’s ears.
My Rating: Minimal
Fiber cement board
Fiber cement board and cement board are closely related.
You’ve probably heard of Hardiebacker tile backer board. Fiberock is another popular product in this category. It’s a sort of gray/beige colored board and is available at any hardware box store.
The tile backer boards that have already been mentioned are fairly easy to cut by scoring and snapping. But Hardiebacker and its competitors are not nearly as easy. It’s much stiffer and harder.
Cutting it in half is much easier than cutting a 1-inch strip off the edge. You can use a skill saw or handheld grinder with a diamond blade to cut it but it’s will get dust everywhere. Including your lungs, if you don’t wear a mask.
Some have found that Hardiebacker shears work well and don’t create too much dust but the drawback is that the edge isn’t always a clean cut.
For installing make sure to use the proper screws (or galvanized roofing nails) when installing. I prefer screws because they don’t bang on the wall and cause cracking in the sheetrock in the rest of the room.
The seams should be taped with alkaline-resistant mesh tape and thinset.
Mesh Tape: Don’t skip this step
But when it comes to getting wet these fiber cement tile backer boards hold up well. They will soak up water but will dry out without losing their form.
Because they will absorb moisture there should always be some sort of a moisture barrier when using these tile backer boards in a shower or other wet area.
Either a vapor-type barrier behind the board or a waterproofing membrane on the front. This can take the form of a sheet membrane or a paint-on liquid.
See these posts to learn more about the basics of waterproofing showers and how to build a shower pan.
My Rating: Good
Popular Cement board brands are Durock, Wonderboard, and Permabase.
Like the fiber cement boards, these can be difficult to cut. The difficulty comes not so much from the stiffness but the edges that crumble. It does take some getting used to.
Additionally, they’re heavy which makes them hard to hold on to the wall while you start your screws.
5 Ways to Screw Up your Cement Board Installation on Floors
However, cement boards have improved over the last few years. The edges don’t crumble as badly as they used to.
Permabase is the one that I prefer and I can usually drive screws into the very edge without it breaking off. Additionally, the water absorption is quite low.
You still need to waterproof them like the fiber cement boards above. And use the same screws and mesh tape.
My Rating: Better
Foam Tile Backer Boards
Wedi board is probably the most popular if, for no other reason, that it’s been out the longest. Kerdi Board is another choice with a decently long history and loyal customer base.
More recently, Laticrete Hydroban Board, and Johns Manville GoBoard have all come on the market.
There are some big advantages to these panels for showers:
- They don’t damage the walls as you carry them into the house and upstairs.
- Really easy to cut
- The board itself is waterproof so need for additional waterproofing.
Some boards will need additional framing blocks at the seams. Wedi board seems to be stiffer than most.
How to Install GoBoard Tile Backer Board | Video
The main drawback is the cost and maybe availability.
The foam board itself is typically 3 times the cost of cement board. Then you have to buy the urethane sealant that you use in between the joints of every panel (or banding for products like Kerdi-board).
Also, the stainless screws and special washers. All of that stuff adds up – and fast.
edit: Some of the newer backer boards don’t require washers with stainless screws and can be installed with cement board screws.
But when it comes to performance these are the top performers.
My Rating: Best
Ishwar Khamare says
This is a extremely good article. Very good comparison between various substrates. And each is rated.
I am doing a small shower. And using Hardie backer board on the walls. The problem I am running into is screws don’t go far enough in the Hardiebacker board to make a dimple but stick out little bit in spite of my good efforts. The screw heads get damaged. Is this ok to put Kerdi membrane on this. Your advice wlill be appreciated.
This can be an issue and I appreciate your bringing it up. Hardibacker can be a bit tougher to drive screws into. The best tool to use is an impact driver. This will drive the screws without stripping them out. It’s best to have them a bit recessed with a dimple as you’ve stated. This is the best way to install the Kerdi membrane.
I would like to redo a shower from the ground up and want to use a foam backer board but they are pretty expensive.
There are a growing number of manufacturers that offer foam backer boards – kerdi, wedi, usg, laticrete, nobal, finpan, jm goboard etc.
Rigid, high density foam boards for insulation AND tiling are made from expanded, extruded or polyiso foam depending on the manufacturers. Usg and JM seem to make rigid foam boards for insulation and backer board, Wedi uses Dow for their foam?
Is there a difference between a rigid high density foam board made for insulation vs for tiling?- regarding just the foam for its lightweight and waterproof properties.
If they are the same, can a insulation foam board be used for shower walls IF a waterproofing membrane or liquid such as hydroban liquid or sheet is applied- making it a budget friendly foam tile backer board?
This is a good question and I did talk a bit about foam board insulation values in my post on recessed foam niches on exterior walls.
For starters, not all manufacturer’s make their board out of the same foam. Schluter and Wedi both make theirs out of extruded polystyrene while Johns Manville makes theirs out of polyiso foam.
Is the insulation board found at Lowes or Home Depot the same as the EPS building panels such as Durock and Wedi? They definitely don’t have the coatings that other manufacturer’s put on them that help tile to adhere. But I have seen some guys experiment with adding a liquid waterproofing, such as Redgard or Hydroban, to a standard EPS foam panel. It’s not something that I would recommend on the internet but I wouldn’t have an issue tinkering in my garage with such a concept.
If you do decide to experiment please report back so others can benefit from your findings. Otherwise, if you want a sure thing I recommend Wedi board. It’s nice stuff. :-)
Another option you should be aware of is Finpan’s Propanel. It is used just like any other inherently waterproof foam core board like Wedi, etc. It isn’t quite as stiff as Wedi so depending on your install you may wish to use extra blocking behind it – we simply spaced the studs at 12″ instead of 16″. This worked out very well for a very large custom shower with 9′ ceilings and angled walls.
It was easy to install and waterproof – all by myself with no helper. We are about to build out another custom travertine shower and will absolutely be using this again.
i hope i can get a question answered here. my tile guy said that the xp purple rock is fine for tile backer board- i see when he cut the hole for the shower thing that it has the little round styro beads or whatever the heck it is and all i can think is that if my shower [ cant think of name , my brain wont spit it out !!] thing springs a leak , is it going to get wet and expand and ruin tiles. My other friend says it will probably be fine – i dont know what to think except its too late…
I’m not familiar with that product but it sounds like it’s a “new & improved” version of greenboard. It’s still gypsum based and it’s a very minimal product. It’s not what I would want in a shower and is not the type of material that you would buy if you’re building a shower for the long haul.
I’m ripping everything out of a small bathroom. I just want to make sure I’m using the correct supplies. Would you confirm this?
Tub walls will be using 1/2 inch USG Durock with mesh tape. Will also use Redgard on the Durock backers. Is it ok to use green boards for the rest of the bathroom? Tiles on green boards (rest of bathroom, not tub walls) will only go up to 42 inches.
Is there a special sealant I should on tiles AFTER they have been set? What type of caulkin should I use?
This is my first major project on my own so any and all help/ suggestions are greatly appreciated!
The products seem good. Greenboard is ok on the bathroom walls as far as I know. Depending on which grout you use you may need to apply a sealer afterwards. I have two different posts about grout that may be of interest to you.
For caulk I recommend 100% silicone that is color matched to the grout. Most manufacturer’s make this type of silicone. Note: 100% silicone is not the same as acrylic or latex silicone found in the big box stores.
UPDATE: We won’t be using Finpan anymore. We used it three years ago and recently inquired again. After all this time, they still don’t have a distribution channel setup, and we live near NYC and Philadelphia, hardly out of the way.
On one hand, Finpan costs less than competing products (Wedi and Kerdi board). But, it isn’t made of the same quality (it’s not an extruded core) so the boards have more flex and so will require smaller stud spacing or additional blocking. Otherwise, if someone pushes against the tile (or falls against it), the backer board behind might flex, resulting in cracked or detached tiles.
Without a proper distribution network, the bottom-line cost of Finpan Propanel is about equal to getting the vastly superior Wedi product (Finpan’s shipping cost is excessively high). So, we have changed over to just using Wedi, which is just as well since their boards are incredibly well made, and save the time to install any extra blocking.
Purple rock is essentially still drywall, with a “moisture resistant” facing. It should never (IMO) be used in a shower. If there is a leak behind the wall, or simply even enough long-term moisture build-up, that product will weaken and fail, and you’ll need to redo the shower.
There are lots of proper backer boards that are impervious to water damage – any of those should be used. They are all listed here and are really not expensive – well except Wedi – but it’s a joy to use, very fast, and saves an extra waterproofing step since the product is inherently waterproof.
>> Is there a special sealant I should on tiles AFTER they have been set? What type of caulkin should I use?
Tiles will only need to be sealed if they are natural stone (travertine, marble, etc). We love it but some people don’t wish to reseal their tile every few years – honestly it’s not a big deal. If the tiles are ceramic or porcelain they won’t need to be sealed.
However, the grout WILL need to be sealed (unless you use epoxy grout). But, you need to wait 72 hours or more before you seal it. I personally really like the sealers by Aqua Mix. If only sealing grout, make sure you get one that is NOT an enhancing sealer – or it will darken the look of your grout (wet look color).
As with most things like this, it makes sense to Plan, Plan, Plan and then do. From your questions, I’d suggest that you make sure that you have your ducks in a row before doing something prematurely or incorrectly. it’s not rocket science but there are a few things to know about, for sure.
When it comes to grout, it’s a minor thing. The toughest thing is picking a color that you’ll really like. We prefer very thin grout lines and use a “sandless” grout on the walls (sanded grout is for large grout lines – yech!). Regular grout is very forgiving, and the “haze” can be easily cleaned up days afterward, especially with a good scrub like Aqua Mix Nano cleaner.
We also like using epoxy grout on the floors. Epoxy grout is great but you MUST read and follow the directions exactly – it is not forgiving, sets up fast, and there is more prep – you need to coat the tiles with soapy water before and clean everything very quickly and thoroughly right after grouting.
Very awesome article and comprising, really helpful and easy to absorb. It really made me make up my mine in what to use in my bath room, something for a few dollars less is not worst it so you just better do it right the first time and sleep like a baby knowing that you did it right. I’m going with Wedi Board and thanks to you I have to do more research LOL… Glad that God put people like you in this earth :) Thank you
Alan Schollmeier says
I used go board on walls around my bathtub. I intended to tile, then decided to glue a tub surround on the walls instead. Will the walls stay stuck?
carol anderson says
I live in an area that has frequent small to medium earthquakes. (Olklahoma)Tile in my bathroom is starting to crack and I want to completely retile my shower. what is the best backing to use that will have some give to the tile or grout. What would you reccommend to prevent my new tile job from cracking???
I would think so. It’s probably a better way of doing it than having sheetrock behind.
I think the most important thing would be to put movement joints in the new tile shower. All the corners and changes-of-plane will have to have a gap and the gap would be caulked and not grouted. This will allow things to move. I have a recent post on this very subject that you may want to look at.
Otherwise you could use a membrane over the backer board walls similar to how you would go over a concrete floor that has cracks in it. The membrane would have to be a crack isolation membrane (A118.10) and also a waterproofing membrane. Nobleseal TS is one example. Redgard would be another. I really don’t know how effective this would be in this situation. It could help and definitely wouldn’t hurt anything.
The movement joints I mentioned at the beginning would help the cause without a doubt.
Thank you for all of your help with my bathroom remodel. In my bathroom, there was a five foot tile tub surround and then about 22 inches of drywall above it to the ceiling. I’ve taken out all the tile, but the drywall on the very top is still there. If I am using Wedi board and make a flush transition to the drywall using sealing tape, could I continue tiling to the ceiling on the drywall? There won’t be any water hitting that area. Thank you!
Drywall at the top is fine. 22 inches seems a bit much to me though. I guess it would depend on the height of your ceiling. Usually you want the Wedi board to be at least as high as the shower head.
Julie Eckscato says
My husband used Hardibacker 500 mold block cement board, and a vapor barrier between the cement board and the studs. There is an area behind the shower wall that is not sheetrocked on the other side. I can see moisture and mold between the plastic and cement board. No water is hitting wood. Is this normal? What should we do?
I don’t know if this is normal or not. On one hand you could say that the system is working as designed being that the moisture didn’t pass through the plastic moisture barrier. But it doesn’t seem to me that that area should see a lot of moisture. So my hunch is that you have an issue with the shower somewhere. Whether it’s an easy fix or not is unknown. If it’s a difficult fix then maybe just keep an eye on it and be thankful for your plastic.
A lot of people don’t think that waterproofing is necessary. You situation shows that it is.
Hi – this blog is fantastic!! I’ve been tiling for over 20 years and have picked-up/learned/remembered several things from your posts/links last nite (was actually up til 5am just reading and looking at all your videos) – so now with 2nd cup of coffee in hand, my question….. I’m building a shower – whole bathroom actually – (ok husband is doing the framing/ruffing “this” time – he’s amazing at that stuff) and I will be putting wood-look tile (6×24) on floor (this is how I found your blog as this is first time working w wood-look) so am really grateful to learn about cupping/lippage issues etc. and offset guides – have a couple questions I’d like to ask you but this is about water barriers.
I’m planning on using 40ml barrier+cement board (taped/mudded of course) but also plan on liquid water proof over cement board — over kill? probably but I’ve liked results previously along w the lessened worry and feel the expense is minimal insurance — am I nuts to do this? (husband will invariably research/validate every syllable I utter on this project) ((no I won’t dear!)) (you’re validating what I’m typing right now) ((ummmm…. sorry)) (eyeroll)
anyway – is it wrong to double water proof as planned?
I don’t think it’s a good idea and because, in theory, water could actually get trapped in between the two barriers. Water vapor could actually pass through the surface barrier and be blocked by the barrier behind. We call this a “moisture sandwich”.
What you can do is use a 40 mil shower pan liner in the shower pan. You would flash this up the walls about 8-12 inches typically. Then use a liquid (or Kerdi-type sheet membrane) waterproofing on the surface. This would be applied on the cement board and down to the pan but not on the shower pan itself. That way the two barriers would overlap. Hopefully I’ve written that so it makes sense.
Thanks for the comments and I’m glad that you enjoy my blog. :-)
That is a good concern to be forewarned about – didn’t think of the water getting locked in – and yes your suggestion made sense – thank you for such a quick reply – have a great new year!
Chris P says
Thanks for the site DIY TILE GUY !
I have been using various types of 1/2 cement board on tub and shower walls and 1/4 fiber cement boards on bathrroom floors with 1/8 inch gap.
I use 15 lb felt with 100% overlap over the studs on walls.
When doing floors I use 1/4 x 14 notched trowel with thinset over the sub floor. I use the appropriate coated screws for both floors and walls and alkaline mesh tape all seems and corners on both floors and walls.
Lastly I always leave about 7/16 inch gap between cement board and tub or shower base, bringing the tile down to about 3/16 gap and fill the void with 100% silicone to finish the job. Do you have any recommendations / criticisms, I value your experience.
Sounds like you are doing everything to the letter which is great! I don’t have anything to criticize but I would encourage you to try out some different products and expand your horizons. Even if you don’t decide to switch it’s nice to have some experience with different products. For example, you may run into a situation where you need a thinner floor and decide to use 1/8 inch Ditra instead of 1/4 inch backer board. Otherwise keep doing what you are doing.
Thanks for the comments.
Dan P says
I am getting ready to imbark on my first bathroom remodel and I keep hearing contradictory statements on what to do for waterproofing my tub area before I tile and what I should put on the floor before I tile that. Some say place a sheet of plastic barrier between the studs and concrete board and then seal the concrete board with a membrane. And others say to just use the plastic and nothing on the concrete board. While others are saying to just use the concrete board and nothing else.
I don’t want any leaks and expecially don’t want my tile to fall off the wall either. Any suggestions on what to put on starting with the studs?
Allen Rohner says
You’ve answered quite a few questions for me on installing tile. Thank you. How is the seam treated between wonderboard and the fiberglass reinforced shower pans. As a second question, do you prefer using premade shower pans or laid up ones built on site. I know that one problem with premade is size limitations. In my house I wanted a four feet by six feet shower pan. I couldn’t find one, but have stood on them in hotels. Still looking. Thanks, Allen
You want either a sheet of plastic behind the cement board or a waterproofing membrane on the surface. Not both.
The membrane on the surface is the better of the two.
Shane Allen says
Redoing a shower tub wall and found out they used cement board for the bottom half of the wall, then some sort of really crumbly, brown board on the top half (I think it was green board?). I cut the top where the tiles stopped a few feet from the ceiling and tore everything to the studs from there down.
Plan on using cement board or foam board to build the walls back, and tile over that. But my concern is where either substrate will meet with the remaining wall boards. How do I best seal this area? Meshtape and thinset?
As far as the seam question I will have a post coming out on this in about a month. But the short answer is that I caulk it. First I waterproof the board and then I caulk the gap between the backer board and the tub flange.
And for the second question I prefer doing mud shower pans. I know how to do them and the materials are inexpensive. I think you’re referring to foam pans when you talk about premade. I think the foam pans are a good DIY option because the slope is built in and they are a little easier to waterproof. But, like you mentioned, things have to be set up just right for these.
For a 4×6 pan I think you’d probably have to buy the extensions that they make and add them onto an existing standard size foam pan. Or buy a custom made one.
Thanks for reading my blog and I appreciate your participation.
Yes. The best way is to try to transition outside the wet area but still inside the area to be tiled. You want to mesh tape and thinset the cement board to the drywall. Maybe 1-2 inches before the tile stops so that the tile covers that seam.
I read a lot about membrane/barriers but have not read anything pertaining to applying red gard on durock on an outside wall with fiberglass insulation paper faced…..assuming you still red gard it beings the insulation is paper and not plastic faced?
I know some people say to defeat the vapor barrier on the insulation but I don’t know enough about building science to recommend doing that. What I know is that a shower needs a waterproof barrier. I don’t worry too much about the paper on insulation.
I suppose you could slice the paper faced insulation and install a sheet membrane on the shower which would act as a vapor retarder also? To me that seems like over thinking it.
SA Royal says
Hi tile guy. I am in the midst of bathroom project from hell. Tiny room. “Simple project”. Simple, after the basement floor was busted up and pipes put in. I accepted a good quote by one guy who couldn’t start for 2 months then left town. Hired another guy off c-list (never again) and got pressured into giving him money upfront for materials and as downpayment for plumber, and he left with $2000 never to return. (eyeroll. angryface.) Next guy did framing, plumbing and electric and recommended that the sheetrock / tile guy (who I had to hire separately) use greenboard all around. Tile guy says, yep, that’s what he always uses. So, I got tile and all the fixings yesterday for install today. But felt nagged by thinking surely that drywall would need to be sealed really well first if used in a shower. The folks at HD said to use PVA on the greenboard before tile.
NOW, after reading a million contradictory opinions on many different forums until 4 in the morning, 99% of whom say NEVER USE GREENBOARD IN A SHOWER, don’t use PVA under tile, and even Redgard is not advised, I just want to cry. I’ve stopped the presses, set the sheetrock/tile guy to idle and need to figure out what to do next.
#1 Should I just have him take out the green board that is in the shower itself and replace it with…. Kerdi board? (I like that that option sounds light weight and easier to use than the usual cement board.) Or, should I go with wonder board or the like?
Or, #2 can he fix Kerdi board on top of the greenboard and then tile over the Kerdi board and seal all the edges?
#3 If he puts Kerdi or some such thing over greenboard, do I need to use liquid seal first?
To clarify, this is a tiny basement bathroom – basically a box built on slab in an unheated, basement / laundry room. The floor and shower “pan” of this new bathroom box is about 6″+ of concrete. (I am still trying to figure out how to seal that.) I am on a very tight budget, especially after the $2k rip-off, and just doing things as I can afford it. (But desperate to finish soon and reclaim my laundry area and daughters basement bedroom)
I’d LOVE to hear your thoughts. Thank you so very much.
SA Royal says
Scratch that… just got my own answer, I think. I’m taking the greenboard out and install Webi board in its place, with tile over that. There is greenboard on the ceiling too that I will treat with PVA and then paint. The ceiling is very small and board is well attached, so thinking sagging won’t be a problem.
Wedi board is a good option. Another option available to you is to simply put Kerdi fabric (not board) over the greenboard. I think USG Durock fabric is ok over greenboard also. If you go to Schluter’s site they have good information and video’s on this.
We have builder installed pebble tile in the shower. The pebbles are black and so is the grout. We are starting to see white colored cracks in the grout. Does the shower just need to be regrouted? Should we use a light colored grout this time? Could there be water seepage through those cracks? Thanks for your response
It sounds like efflorescene. You might be able to mask it temporarily with grout sealers but the only solution is to fix the cracks which means tearing out the pan and redoing it.
Help, I have been reading and trying to understand this process I’m a 70 year old women and would like to hire some one to put wood look alike porcelain tile, it is a quality product will be putting down approx 1200 sq ft I have been getting very high BIDS example…HARDEE BACKER SCREWS#10BY 1- 5/8ZINC PLATED STEEL FLAT HEAD 600 PACK 6-SHEET MY QUOTE IS 133 PC @48.71 EA FOR THIS ONE LINE ITEM MY QUOTE ON THIS IS$6,478.06 I think this is very high and have suggested using a less expensive product this is going on my family room, study, sun room and dining room can you please shed light on this for me THANKS SO MUCH
I just made a mistake on the product that totals $6,478.06 the product is Hardie Backer 3×5 x 1/4 sheets was told i need 133 sheets @$48.71 THANKS AGAIN
The cost of Hardibacker board is about $10 per sheet for just the product. If the $48.75 is per sheet and that’s installed then that seems quite inexpensive to me.
However if that price is only for the material itself then it sounds like a rip off.
Also, if its 1200 sq ft then that’s only about 80 sheets of Hardibacker. So there’s either more than 1200 sq ft or you’re getting about 45 too many sheets.
Julie Eckscato says
Thank you so much for your reply. The water is coming from a horizontal seam in the backer board about 18″ from the floor. Would you suggest taking the bottom 24″ of tile off and sealing the backer board, completely re-doing the shower walls, or another solution? Thank you so much.
It’s hard to know why water would be coming from a seam that’s a foot and a half off of the ground. My suspicion is that it’s getting in somewhere higher and traveling there. I would check the corners.
To answer your question though, yes, you can take the bottom 2 feet of tile off and repair the seam that’s below it. But you may be fixing the symptom rather than curing the problem.
Tim B says
What a great site! I have a couple questions about Schluter. I’ve ripped out an old leaking shower down to the studs (and beyond, a sad story). Now I have to decide what the replacement will be. My tile guy is old school and wants to use 1/2″ of greenboard covered with 1/2″ Hardibacker, and a traditional mud pan. He allows that coating the Hardibacker with Red Gard might be a good idea. I’m looking at some of the newer materials, and Schluter seems to be very popular. I’ve watched the videos on their website, they make it look easy. One thing is clear to me: success with Schluter is a function of your expertise with thinset and a trowel. On johnbridge dot com someone described a water test of a kerdi shower installation where water was wicking out all over the place (he’s got the kerdi band UNDER the floor membrane, which is not how the Schluter video says to do it, but should that really matter?). Poor thinset work? Probably, but here’s my problem: even if done perfectly, thinset is not waterproof. Others on that site were saying 1/4″ of wicking is normal. For a waterproof system, I’d say 0″ wicking is what you want. So I’m wondering if that could be achieved with a couple of coats of Red Gard over any exposed thinset. What do you think?
Also, does anyone know why Schluter insists on unmodified thinset? Just curious.
Hi Tim and thanks for checking out my site. :-)
A traditional mud pan is fine if it’s done properly but I don’t like the idea of gypsum behind the hardibacker. I’d rather just see the walls furred out. And the Redgard is essentially a must.
As far as the Schluter Kerdi Shower System goes, they have good videos and instructions for their system. It’s a good system if done well and their instructions are followed. Schluter has never claimed that thinset mortar is waterproof. What they claim is that their system is waterproof. This claim has held up over the years and the fact that other companies have followed suit is further proof that it works.
However, in my experience, water wicking up the walls during a flood test has never been an issue. I know that I’ve tested every one of my shower pans for over 15 years and with all different wall materials. What I do notice is that water seems to “wick” the most when you’re filling the shower pan with water. The water is usually splashing around a little bit at least and it shows on the sides of the walls.
This is most noticeable on Wedi Board showers because they are dark gray and the coating is cementitious. But I’ve seen this with Kerdi, and Noble ValueSeal, and others.
What I am concerned about with a flood test is the water level. I measure the water level from the same spot every time and that’s what I feel is important to keep an eye on. I suppose if water climbed up the wall I would be concerned about that but I just haven’t seen it. And I’ve let flood tests sit for a couple of weeks before. Water sitting in the shower pan is a good way to keep other people out of there. ;-)
Schluter has a FAQ section on their website that goes into the modified vs unmodified thinset reasoning. My take is that thinsets have come a long way and their “science” is outdated on this. Furthering my point is the fact that they just came out with their own line of modified thinset mortar called All-SET that can be used with their products. They claim that it’s specially formulated for their products. Maybe it is but it doesn’t mean that other modified’s don’t work with their stuff either.
Tim B says
Thanks for the quick reply. I’m still wondering about the Red Gard. Is there a reason NOT to use it? I don’t care about a few extra bucks. I do care about never, ever having to worry about the shower ever leaking (been there, done that). This guy was probably thinking along the same lines: https://www.johnbridge.com/vbulletin/showthread.php?t=90727 (scroll to bottom).
Here’s another question. I have 9′ ceilings and plan to tile all the way up. I’ve read that you don’t need the Kerdi board past the level of the shower head, since water doesn’t get that high. They don’t know my kids. So I’m thinking of running the kerdi board all the way to the ceiling. It just seems so light and easy to work with. Is there a functional down side?
I don’t like the practice of using Redgard with Kerdi. I say choose one or the other. If you are using Kerdi for the shower you can use Kerdi fix on all the seams as extra insurance. This would accomplish the same thing as using Redgard. I wouldn’t spread it around like in the photo but use it like you are caulking a seam. Additionally, this practice would probably be ok with Schluter I would think.
If you want to waterproof to the ceiling then there’s no downside to that other than the cost of materials and time.
My drywall that is in the tub /shower now is 5/8 in thick I am tearing the tub out and am ready to put Hardie Backer in but could only find 1/2 in thick(3/8) in what do I do now? Is there anything I could use that’s close to 5/8?
Pick up some drywall shims in the sheetrock section. Usually two of those is 1/8 inch. You staple then to the studs to build out the Hardibacker.
While you are doing this you may as well put a straight edge across the studs and make sure that the studs are flat (they won’t be). Use the drywall shims to make the wall flat.
When you are done coat the Hardibacker with Redgard or similar waterproofing. The shims are card board and you don’t want moisture getting to them.
Hi. Great informative article. I’m just about to do my bathroom. It has timber stud walls and I’m planning to use foam backer boards above my bathtub/shower. What thickness of the foam backer board do I need to use? It will go directly onto my timber studs…
The best thing to do on this is to call tech support for the brand of foam board that you are using. I would think 1/2 inch would work for sure but I’m not sure how much thinner you could go. I think it will depend on the timbers. Most importantly is to find out how they want it fastened. There may be special requirements being as it’s over timbers. A call is the best way to find out.
Ralph sogliuzzo says
I am replacing a tub and adding a shower. I have removed all but the top foot of green board in the alcove. I plan to install 4mil vapor barrier then hardibaker. Do I have to sand the paint off the green board that remains or should the hardibacker go to the ceiling?
It’s fine the way that it is. If the Hardibacker is at, or above, the shower head then it’s high enough. The mortar will stick to painted drywall just fine.
Hi. We are planning to remodel our bathroom and remove the tub and have a tiled shower installed. The contractor uses John Mansfield GoBoard and sealant. Should we be concerned that this product has not be around very long? He has been using it for about a year and a half but we don’t want to make a mistake with a product that might fail down the road. We are searching the internet for feedback but really have found very little about this particular product. Is it as good as the Schluter system, etc.? What are your thoughts please?
Also, any concern with keeping the shower drain in the approximate same position as it was with the tub? Is it just a matter of ascetics? (I would rather not be standing on the drain.)
Thanks in advance for your reply.
The big advantage of Johns Manville GoBoard versus competing products like Kerdi Board or Wedi Board is that it costs quite a bit less while still providing the same, or similar benefits. While I don’t consider GoBoard to be the best in its class it’s not a product that I feel should be stayed away from either. The most important ingredient for success is that it’s installed properly.
What I’m wondering about is how the shower pan is to be waterproofed. Johns Manville doesn’t make a foam shower pan- at least not to my knowledge. So your contractor is going to have to use another product to waterproof the pan and that’s where things can get interesting because he will have to tie in the waterproofing of the shower pan to the walls. This is where a system like Schluter or Wedi is an advantage as they make and guarantee an entire shower.
As far as a drain goes, whether it remains offset or is moved to the center is more a matter of personal preference. I prefer them centered because I find the slope angles to be a bit steep when the drain is at one end. With it centered the slope is much more gradual and consistent. But it is in the middle and will be stepped on.
To sum things up, I don’t see anything inherently wrong with GoBoard that would cause a failure. But because they don’t offer a complete system the instructions on how to make the shower completely water tight are less clear- and that’s where mistakes could be made.
I’m putting in a new shower. I have installed a traditional Oatey PVC pan liner per the manuf. specs. I am at the point of deciding what backer board to use. I see your comments about Wedi and it looks like a very good option. One thing I cannot tell online, from the Wedi site or from the local contractor in Atlanta who sells Wedi is whether or not Wedi wall panels (1/2″) can be used with a traditional PVC pan liner.
Everything I see online assumes the Wedi shower pan is being used.
Do you know if you can do this? The Wedi site does not give any guidance nor do they provide a customer service phone number to ask questions like this. Everything seems to be email.
Thanks in advance.
Yes, Wedi panels can be used with a traditional mid pan and liner. Typically Wedi panels are used with their foam shower pans, like you mentioned, but also can be used with a mud bed with a waterproofing membrane on top. They have a product called Wedi Subliner Dry for this purpose.
You could also use Wedi wall panels with a mud pan and liner. Personally, I would prefer cement board or Hardibacker because they don’t flex as much.
The stiffer wall board can help keep The bottom of the board that overlaps the liner from flexing.
But the Wedi panels will work just fine also.
Jared Dringenburg says
Love this article, it has really helped me install my backerboard. 2 questions though.
1) do you need to apply a “Waterproofing membrain” to Permabase or Durock if they are good with water already?
2) I have just put up 1/4 inch permabase in my bathroom and while much if it is very sturdy there are a couple wider sections that have a slight bend if you push them. Will this be okay after applying thinset and tile or should I take off the permabase in the areas of concern and apply a couple supporting cross studs? (first big remodel project so any advice you can give is appreciated).
Yes, you should apply a waterproof membrane with the cement board walls, although, it’s not a guaranteed failure if you don’t. I’ve seen drywall showers from the 1980’s that were in ok shape 30 years later. I’ve also seen many that fail and do structural damage to the home.
Waterproofing, in the grand scheme of things, is money well spent. If you want to do the minimum then you could install some plastic or tar paper behind the studs and still be ahead.
For the Permabase on the walls, the 1/4 inch isn’t what you want to use. Not only will the 1/2″ Permabase match up with your drywall better, but 1/4 inch Permabase is too flexible to have 16 inches of unsupported space between the studs.
I recommend 1/2 inch Permabase and the flexing issues will go away.
Linda Randall says
I am tiling an uninsulated basement floor. Can I apply foam board over the concrete floor using thinset, then install heating cables over this, then thinset the tiles over this ? It seams to be the way its done in England where they have been using electric heating cables extensively for a long time.
Are there any shower wall or pan waterproofing methods that would cause problems with thinset adhesion to the backing surface?
I’m building a 4’x6′ shower using Hardibacker on the walls sealed with Redgard and a Goof Proof Shower Kit and Oatey shower pan liner to build the pan, and don’t particularly want the tiles to fall off the walls or pop loose from the pan. I’ve rebuilt 3 entire homes over the decades, but this is my first attempt at building a tile shower from scratch.
Yes, this is good. You’ll want to make sure that the board is weighted down while it dries.
The best thing is to use high-quality thinset mortars and get good mortar coverage on the back of the tiles.
George Kelley says
Can NobleSeal or similar be installed over Densshield. My father in-law started a remodel of a walk-in shower and had put up Densshield before passing away. I’m picking up the project and would like to use sheet membrane. Thanks.
Yes. It’s always a good idea to look at the specific instructions as they can vary. Noble tends to be more conservative with what they recommend as substrates.
But the answer is yes, you can go over Denshield with a sheet membrane and I think it’s advisable to do so.
George Kelley says
Thank you for prompt reply. I had downloaded the literature from both companies, yet it was still not clear given the “built-in moisture barrier” of the DensShield. Thanks again.
Dennis Lynch says
FYI, while some of the foam that you see in your local building centers may Be from the same manufacturers (you can easily tell who provides what just by the colors of the foam) they are not the same. While they are extremely similar and have the same properties, some foam boards are either too rigid or too flimsy. I am a sales rep for wedi Corp and our manufacturer makes our foam specifically for us and to our specifications. A foam board that is too rigid can actually crack with normal movement in a structure and foam that is too weak will have too much flex in the wall cavities. Also, while some folks are using foam from their building centers and making “waterproof” creations, a huge part of our patent is how the coating and the fiber mesh is adhered to the foam. For lack of a better term, it is microscopically imbedded into the foam to bond and also to create a “dam”. So to answer that question, while there are many similarities, there are vast differences. If it was as simple as painting a waterproof coating over a cheaper foam, we would be able to do that and offer a cheaper product, cost wise.
Hi Dennis. Thanks for your comment and I appreciate your input. It’s nice to get some manufacturer feedback on here from time to time.
Jim Oliva says
This is a very good article. The industry standard in the 1960’s and 70’s was to use drywall. in the 80’s it switched to Green Rock (moisture resistant drywall.) then Green Rock was replaced with M&MR drywall (mold & moisture resistant) Grout is not water proof, and moisture will wick through it. That is why drywall of any kind failed horribly, giving tile a bad reputation. Many people still are resistant to tile because of it. The Building Codes finally banned the use of drywall of any kind behind a shower around 2006. I have never been a fan of the fiber cement, or cement boards, as you pointed out, they soak in moisture. I have demode showers with Durrock, and it had literally turned to sand on the lower part that was constantly wet. I have been using G/P Denshield since the early 90’s with no problems. Since then, all the Gypsum Board manufacturers have tile backer boards. Sclurter was the pioneer in the waterproof backer-boards and decoupling membranes. I attended a Schluter seminar around 2011. It was well worth the time, Personally, I don’t see the advantage and added expense to go with the Kerdi board over the Gypsum tile backers, and ii was concerned with strength of the Kerdi board, which is essentially a foam board. I treat the gypsum backer like the Kerdi, taping all the seams & corners. along with sealing all screw heads. The best way would be to float the walls with concrete, but that requires a lot of time & skill, and would significantly increase the cost. I have torn out many showers on concrete, and they were solid.
I appreciate the response. Everyone is going to have their preferences but most important is doing things correctly. A lot of times people think the gypsum tile backers are ready to go once they are installed. But, like you mentioned, extra work is needed to get them to be waterproof.
But I’ve converted over to the foam backer boards. Just loading them in the house vs. cement board was a sales pitch in itself. :-)
I need to validate two primary methods in my shower remodel…
1) I’m planning on using Wedi ligno with corresponding board to the ceiling followed by drywall at the ceiling. I’m assuming I would place the Wedi board flushed with the drywall (at the ceiling) and just seal with their brand sealant. Is this accurate? I essentially want to tile the whole shower and not the ceiling
2) I’m planning on laying down 3/4″ plywood for the subfloor followed by 1/2″ Wedi board prior to tiling. In the shower I’m planning on laying down 1/2″ plywood instead such that I can place the 3/4″ curb-less shower base to create the walk in shower transition. Do you see any issue with this design? I’m really trying to maximize my vertical space in the bathroom. Is there another option you recommend? I could potentially go with the Wedi Primo (vs. Ligno) to the floor joists but I would be dealing with a 1/8″ gap above or below dependent on utilizing 1/2″ or 5/8″ wedi board on the floor.
Appreciate your time and support!
You really only need Wedi Sealant up to the shower head, or so. You can go higher with it if you want but it’s not required. You would need to tape and mud any seams above this point with thinset and mesh tape if you decide to forego the sealant at this level.
So if you are installing Wedi board all the way to the ceiling then you don’t want to put any sealant in the very corner seam- where Wedi board turns into the ceiling. Doing this can make a mess on the ceiling that wouldn’t be covered with tile.
But if Wedi board transitions to wall board which then transitions to the ceiling -then it’s ok to use sealant between Wedi and drywall as any sealant would then be covered by tile.
2. The way Ligno is designed is that it’s 3/4 inch thick and is supposed to sit directly on top of the floor joists so that, once it’s installed, it sits flush with the subfloor outside the shower.
To accomplish this there is supposed to be plywood subfloor that is installed in between each floor joist. So essentially the shower subfloor is 3/4 inch below the main bath subfloor. Wedi explains what their requirements are for this in their instructions for Ligno.
I’ll post a photo on my Twitter feed that shows what I’m referring to. Hopefully that will make things more clear. Please let me know if you have further questions on this.
Also, with this arrangement, 1/8 inch Wedi board is ideal outside the shower as opposed to 1/2 inch.
We are redoing a small bathroom. Removing the existing enclosure and tiling the walls. My question is whether we should use Densshield behind the tile or Duralock? Someone told me what Densshield has an extra barrier to it.
Denshield does have an additional water barrier but I’m not a big fan because it’s gypsum based and it’s oftentimes not waterproofed correctly. If the seams, edges, and penetrations aren’t waterproofed then the water barrier doesn’t do a lot of good.
Durock, or any cement board, is made out of cement which means that water isn’t going to degrade it. However, it would need an additional waterproof layer to stop water from penetrating through. A lot of times people will use a paint-on liquid waterproofing which is fairly economical.
Excellent. Thank you sir! So basically for #2 I would lay down 3/4 ply and only put 1/8 inch Wedi board down for the bathroom floor section outside the shower. I didn’t think this was possible, but good to know.
Yes. 1/8 inch board is ok as long as there are fasteners and thinset underneath.
This is easy to remedy. As long as your screw head is flush with surface just take a stiff edged putty knife or 5 in 1 tool and scrape the protruding material around screw head off flush. It helps to have a sharp edge on putty knife and may require scraping in different directions bit usually it will remove it
what about installing Laticrete right over purple/green board ?
They don’t want you doing this. It might work but it’s against their instructions.
Wanda Chappell says
We are building a shower in our downstairs bathroom and have purchased Weidi Board for the walls in the shower along with their screws, sealant etc. We are useing a Kolner Fiberglas shower pan 48 x 34″ already installed by a professional plumbing company. We’ve done extensive reasearch but like a previous questioner have found little info on details when not useing a Weidi base. Our question is how much of a gap should we leave between the bottom of the Weidi board and the top of the base? And should we notch out the back of the Weidi board so it sits flat with the transition from the flange to the wall studs? We are looking to start this part of the job today and your valued advise would be greatly appreciated.
I’m not sure that there’s a standard for either one of the things that you’ve mentioned. But if you rest the backer board above the shower flange then I would think 1/8 inch gap would be OK.
If you want to notch out the back then I would probably raise it up off of the shower pan 1/4 inch so that water can flow underneath it. Although it really shouldn’t matter if the board comes into contact with the shower pan. These are just my opinions. ☺
We are reinstalling a new adhesive shower enclosure that was previously glued to green board. I believe the green board was installed with not enough clearance from the shower pan as mold and mildew crept up the existing boards. When we tore out the existing enclosure it pulled most of the paper from the boards so I would like to replace them. My question is, what material do you recommend using if we are planning on replacing the enclosure with adhesive panels?
I would assume that if you recommend a cement board that we wouldn’t need to waterproof?
Thanks in advance
I would think a cement board, fiber cement board, or even a product like Denshield would be preferable to drywall and I don’t believe that they would need to be waterproofed if they are simply acting as a backing and are not part of the waterproofing system.
But it’s a good idea to check the instructions of the shower system that you’ll be using as I don’t have experience with this type of shower enclosure.
I stumbled on this site after reading about backerboards and which one to use. I have used Kerdi membrane on hardie backer but I have become a little impatient with weekend diy work at home. So I am reading to take the plunge into the foam boards. My problem is that I just bought the schluter niches, and surround flange, etc. I can’t afford paying $77 to $100 plus for their foam backer board. I did see some Goboard and Durock foam board, and Wedi. The first one cost $22 per 3’x5′, then we are talking $40, and finally $55 respectively. The box stores ask me to spend $39 for each 12 boards minimum… What? Am I tiling the entire bathroom and bedroom? Ridiculous. I know, there is a question coming… here it is. I read here you can’t mix Goboard with schluter, if I understood correctly. Can I then mix wedi board with schluter niches? They don’t have the size (Wedi) I need, and if not… the box store will be angry because I am returning all schluter things and going Wedi. They same question would apply to USG Durock foam board. I just want to get this over in a week or two (or less). I haven’t started but just want to avoid any hiccups. Did you get the question? Great site, I do appreciate how you explain the differences and convince me to move into Foam board.
You can mix and match whatever components that you want but you can’t expect one company to guarantee someone else’s products. Every product that you mentioned above is fine as long as it’s installed properly.
You might be interested in my posts on building shampoo niches. There’s one that shows how to build from scratch which would save some money but take more time.
Foam boards aren’t cheap but they are selling. I just went to a trade show recently and everyone either has a foam panel or is coming out with one. Hopefully, the prices will come down accordingly.
Thanks. I will check how to build those and saving money always makes the mrs. happy, and the mantra is happy wife, happy life.
Chris D says
So where does Schluter’s Ditra membrane fit into all of this? I’ve read that it’s a decoupling membrane (not exactly sure what that means) and it will add about an 1/8″. Does this have advantages or disadvantages over the Kerdi for wall or flooring applications? I’m getting ready to do both (floor and shower walls) in my bathroom and was considering a thinner 1/4″ backer board on the floor (over 3/4″ subfloor) where the extra 1/8″ might come in handy to match the finished floor height in our hallway. Or is any membrane overkill on a floor (maybe just a liquid sealer over cement board?)?
Great article and thanks in advance!
So the two different products, Kerdi and Ditra, have two different uses. Kerdi is used for walls and waterproofing wet areas but Schluter doesn’t want it used for floors (other than sloped shower floors).
Ditra is used for floors, but not walls, and has some waterproofing capabilities but shouldn’t be used in a shower environment as the primary waterproofing membrane.
So as far as Ditra vs cement board for floors, it just depends on what you want to accomplish. But they both perform essentially the same function: to provide an underlayment for tile over a subfloor.
Typically, the 1/8 inch thick Ditra is a better choice for today’s big tile and matching up with neighboring carpet or hardwood. However, it has a minimum size requirement of 2 inch x 2 inch.
If your tile is smaller than 2×2, or really thin, then you may want the 1/4 inch cement board product instead.
Ditra does cost a little more and comes in a 1/4 inch thick size (Ditra XL) as well. However, it’s a little easier to cut and work with.
So the main thing is to pick which you prefer and you think will work the best for your project.
Darlene R Chatman says
Is there an option to wedi pans for the shower floor? They are expensive and I can’t find the right size for my shower. Second floor bathroom with sub floors?
There’s several options from companies like Schluter, USG, Laticrete, Noble, and others. Some of these companies will make custom size foam pans, also.
But you can also create a “mud” pan out of dry pack mortar. Take a look at my Shower Waterproofing Crash Course for more info on this system.
I was planning on using DensArmor Plus paperless drywall panels outside the wet areas. I’ll have to tie them together with cement board and those seams are going to be done with thinset. DensArmor is made with a fiberglass facing. Do you know if it’s safe to use thinset on them? I know you can’t use thinset with regular fiberglass tape because it disintegrates. Didn’t know if the fiberglass backing on the paperless drywall would be the same.
If the seam will be covered with tile then I would just use alkaline resistant mesh tape. If it’s going to be painted then fiberglass is probably the way to go. The data sheet says it can be covered with typical wall coverings, including tile, so thinset and alkaline resistant tape would work fine, I would guess.
I checked the densArmor+ tech guide document and they have instructions for putting tiles over this stuff (including in shower walls and sub surrounds which is disconcerting). Emailed tech support and they say that yes the fiberglass facing on the panels is alkali resistant and yes it will take tile mortar without degrading. Sounds like a sure thing.
Thank you for your help.
I appreciate the follow-up. Thanks!
Todd McG says
I am re-tiling my alcove tub surround with 3×6 subway tile using wood studs with cement board & membrane (per your recommendation). On the end wall separating the tub from the toilet, the toilet side will get drywall with wainscoting topped with chair rail on the lower half and skim coat & paint on the upper half. What is the minimum this wall should extend beyond the tub skirting (my though is to run the tile all the way to the floor in this area)? How do I treat the 4-1/2″ wide edge of this divider wall? Should the edge be tiled or drywall/wainscot/paint? How do I handle the finish edge of the tile at the corner where it will meet the 3/16″ thk wainscoting at the bottom and just the painted surface at the top?
Thanks for all you helpful advice.
As far as how long that wall should be there really isn’t a magic number. 36 inches is sort of common but it’s arbitrary.
You want it or far enough to run your tile down past the tub.
Also, whether you run tile all the way around the end of the wall or just keep the tile on each side is another design decision.
It will increase the difficulty of the install of you tie both sides of the wall into one another.
Your grout joints will so have to line up and the chair rail will have to be mitered around the end.
But it’s up to you what you want to do on that situation. There’s no “correct” way from an installation perspective.
Pro tip: make sure that your toilet will fit before you tile the floor and the wall behind. Some toilets are right up to the sheetrock walk with no tile behind. Then when you put tile behind it doesn’t fit anymore.
Hi, and thank you in advance for your help. I’m probably going to use Goboard, a Johns Manville product similar to Wediboard. This will be for shower walls. Would you put blocking behind the horizontal seams for a foamboard product?
You can add blocking at the seams if you prefer but JM doesn’t require it. I personally have not added blocking at the seams and found it to be sufficient once the sealant was dry. But for the “over-builder” type you may find that you prefer the blocking and I certainly wouldn’t discourage exceeding the minimums.
If using a porcelain shower pan how can my contractor tie that to Durock (foam) or Kerdi Board? Presently he plans to use Greenboard but I will ask him to use either of the above materials. Also, if contractor is used to using Greenboard, is it reasonable of me to expect him to do a good job installing the Durock/Kerdi Board or should I get a contractor that is more up to date on materials? Also, since my bathroom is not that big, I’m thinking it’s probably best if he uses the same materials for all the walls in the bathroom. I plan on tiling halfway up the other 3 walls in the bathroom. It’s easier to clean that paint.
My house has plaster board and we’re gutting the walls in the bathroom but not the kitchen. Is it OK to tile over plasterboard in the sink section of the kitchen or should we also use Durock/Kerdi Board in that area?
My house, being built in the early 1950’s, doesn’t have insulation between the plasterboard and the cement bricks on the inside and regular red bricks on the outside. Will this structural make up cause any problems with using the Durock/Kerdi Board in the bathroom walls since one of the shower walls is an outside wall? Thanks!
I am new to this amazing forum. I really enjoy all of the hints, tips, and opinions. I am hoping someone can advise me on my upcoming project.
I am tiling a large shower with a 10 foot ceiling. Cement board with Kerdi membrane will be used for the shower walls all the way up above the shower head. We are using a Kerdi shower pan with a dry pack mortar extension, of course covered and finished with Kerdi membrane as well. It will be water tested before tiling.
QUESTION 1: Can a Kerdi shower pan support the weight of a ladder for tile installation? I was previously told to put 1/4″ cement board over the pan… Can this be right? OR, Could the advise have been to use a thinset to affix the cement board to the Kerdi shower pan and then membrane over the whole thing for waterproofing?
QUESTION 2: If the cement board is attached, how will that affected how the drain is installed? The Kerdi pan comes with a recessed hole as part of the slope. Or will it not matter since the board would still be sloped?
I have done many tile / building projects as a DIYer over the years, but I am now stumped… Any advise would be very much appreciated. Thanks!
Jim H says
If I am using Hardi cement board, two questions should I put a plastic vapor barrier behind it no second, should I still use a liquid waterproofed over the backer board. This will be in a shower/tub area. Any help is greatly appreciated.
I have a post on the different methods for waterproofing a shower. It’s called Shower Waterproofing Crash Course and it’s accessible through the home page slider.
But the short answer is that I think a liquid waterproofing on the surface is better for most cases.
The drywaller I hired used a product called Diamondback when they installed our bathtub/shower (three-sided alcove). I had never heard of the product and was not happy with the installation as the board didn’t even reach the tub flange. The drywaller wouldn’t fix this (long story, didn’t end particularly well…) but I didn’t have a supply of Diamondback so I just replaced the bottom 12″ on the side and end wall with Kerdi board. I then found out that Diamondback requires modified tile mortar whereas the kerdi board (and kerdi band) requires unmodified. Sheesh.
The cheap way forward for me now is to seal the entire wall area with Aquadefense and fiberglass tape. A more expensive alternative is to just replace all of the Diamondback with Kerdiboard and stick with the Schlutter system.
Quite a minefield for the DIYer. I would appreciate hearing your thoughts. Thanks!
edit: It looks like they want you to caulk the seams without smearing it on the surface then apply mesh tape.
I don’t know anything about Diamondback but a quick Google search revealed that it’s gypsum based and probably similar to Denshield. What I didn’t see was any instructions for waterproofing the seams and penetrations.
I think it’s a good idea to waterproof the seams and penetrations of the Diamondback and use modified mortar over the whole thing. Schluter isn’t going to guarantee your installation anyway because it’s only 12 inches tall.
Mark kildaw says
Great info on your site. Thank you. We are waterproofing and tiling 3 walls of a new shower install and considering timing the ceiling over the shower enclosure also. My question. What product should we use to attach to the ceiling trusses that will be firm enough to hold the tile and not sag and at the same time be easy to work with and waterproof. We are planning on using either cement board with a paint on waterproofing or wedi board for the walls. Will eithe if these work for the ceiling??
Thanks for you help, Mark
Yes, either will work for the ceiling. Wedi board is a lot easier to install on the ceiling and waterproof but either board will work. You do need 16 inch center spacing still.
I am about to start my first tiling project, the bathroom. My question is about the non-shower areas. The rest of the bathroom I’m only going to be tiling halfway up the walls (4-foot 6-inches). The top half of the walls will be painted.
Do I just use a (tile-worthy) backerboard on the bottom half and then switch to drywall for the top half for the paint? I know that will be cheaper but I don’t know if that’s the proper way to proceed.
Yes, that’s perfectly fine. You’ll want the tile to overlap onto the drywall so that you don’t have any backer board peeking out at the top- above the tile.
Alternately, in non-wet areas, it’s perfectly ok to install tile directly over drywall.
Thank you for the response, DTG.
I ended up replacing the bottom 32″ with Densshield and applied silicone to all joints between panels and where the panels meet the flange. I then painted Aqua-defense over all the corners, joints and screws and overlaid these regions with 6″ fiberglass mesh. I applied an additional layer of Aqua-defense over the tape while the first layer was still wet to completely infiltrate the mesh. I also ran the mesh in this way so that it overhung the Densshield by 1cm where it meets the flange.
Anyway, thanks for the reassurance. Much appreciate!
Sounds like you did it right. Good job!
Can I use 1/2” backer board as a tub/shower surround (no tile added) if I apply a cement waterproof membrane on it?
I don’t think that you would get the blessing of the manufacturer but I would think it would work- at least for a period of time.
We are installing an Ariel 902A steam shower and want to make surrounding floor, ceiling and walls water resistant We were going to order 9 4×5 1/2″ sheets of Denshield until vendor called back with a $300 delivery charge. Now we are looking at 1/2″ Hardi backer that comes in 1/4″ and 1/2 ” or Duralock that comes in 4×8 1/2″ or 3×5 1/2″.
What’s our best option for the floor which will be tiled and the ceiling which will have a water resistant wall paper and walls that will be a combination of tile and 3D wall paper?Any help would be greatly appreciated. There is very little information for areas surrounding steam showers. 1/4′ versus 1/2″ in what areas?
I’m glad that you are asking these questions now because it could prevent you from making a big mistake.
First, a tile steam shower has very specific instructions for waterproofing it appropriately. The waterproofing system needs to guard against both water in liquid form and water in vapor form.
Denshield, being composed of gypsum, is not an appropriate product for a steam shower. In fact, this is listed in their own “Limitations” section of their submittal sheet.
Both Hardibacker and Durock are products that are not suitable for steam showers by themselves with no waterproofing membrane. By the way, you want 1/2 inch thickness for wall backer board.
So you’ll need to add a waterproofing membrane that goes over the surface into the cost of this steam shower. If this is a residential steam shower that won’t see continuous use then a system like Kerdi shower system, Durock shower system, Nobleseal TS or ValueSeal are all examples of decent waterproofing systems. Additionally, a Wedi shower system would work with an additional topical coating that they sell.
These are the names of some shower systems that are ok for steam showers and are by no means the only products that will work. Also, I’ve never heard of water resistant wall paper and am extremely skeptical of it being approved for a steam shower.
In fact, all of the steam shower specifications that I am aware of call for not just waterproofing all walls, floor, and ceiling but installing tile on all of the these areas also. And the ceiling should be sloped.
So I hope that you understand what you are getting yourself into. A steam shower is a pretty technical installation and involves more than simply adding a steam unit.
Please don’t hesitate to ask for more information if you have any questions. I would encourage you to look up some of the products that I’ve mentioned as many of them will have their own specifications for a steam shower and will be able to give more information.
I’m planning to use permabase and had to sister out the studs so that the CBU drops down past the tub flange and because the studs are not straight. The sisters are only as long as the studs which means the studs are spaced out but the top and sole plates are about half an inch in. If I put up the CBU over the sisters only without spacing out the plates as well, the top and bottom 1″-1.5″ of the CBU will be unsupported. Is this ok or do I have to space out the plates too? There’ll be some drywall in the same situation.
If you’re looking for proper manufacturer’s advice I would have to direct you to the people at Permabase. Personally, I wouldn’t sweat it unless you don’t feel good about it after it’s installed.
The ceiling area I can’t see being an issue with 1.5 inches of space. It is possible there could be some movement at the base around the tub but I really don’t think it would be an issue.
Permabase is good cement board. The only problem with it is the little foam pebbles can drive some people crazy and you can’t let them blow into the yard or anything like that. But as far as installing it I think it’s the best between Durock and Wonderboard lite.
Ok, thank you.
Is it that the foam bits fall out and litter and don’t blend into the landscape like cement dust would or is there something more diabolical about them like they poison wild-life?
Both. At least if most birds are like my chickens, whose favorite food is Styrofoam and rigid foam insulation.
Alyce Shepard says
My Contractor quoted us for Wedi and now is about to install Laticrete Hydro Ban Board. Why would he do that? Should I be concerned? Is there a cost difference?
Not sure about the diabolical aspects but they do blow in the wind easily and never biodegrade. It’s hard to get white foam pellets out of beauty bark.
I usually use a tarp buy if you’re cutting in your garage it shouldn’t be a big deal.
Maybe this proves that all creatures like what isn’t good for them. ?
They’re similar products and also competitive products. It could be that your contractor prefers the Hydroban brand.
But it’s almost certain that Hydroban costs less than Wedi. But just for the board but all the components.
If Wedi was specifically quoted then that’s what should be used.
Planning a reno of my daughter’s bathroom, which will include removing tile on a tub surround and re-tiling. I’m not sure what is under the current tile, but based on my reading and my feeling that I won’t be able to manage lifting cement backer board (too heavy for my frame and bad back ?), my plan was to use Kerdi board with Kerdi strips and screw system. Can’t seem to find Wedi in my area, your thoughts on Kerdi board/strips/screws? You seem to favor Wedi over Kerdi… thanks!
Hi All! We are planning to use Wedi board when redoing our tub and shower surround. My questions is do we have to tile the Wedi board on the ceiling? Ode prefer not to tile the ceiling but can’t find any other information on finishing options.
Kerdi board is just fine. The steps are a little bit different than Wedi and some other systems but they have good instructions and videos on how to install. If you can get Kerdi-board in your area then I wouldn’t hesitate to use it.
You don’t have to tile the ceiling nor do you have to install Wedi board on the ceiling. It’s pretty unusual that I tile ceilings. Usually, you stop the wall tile at the ceiling.
Brian Nowak says
I’m doing a tub to shower conversion. There is Sheetrock from the ceiling that comes down about 7 inches, then the tile started from there all the way down to the tub. My question is, can I put up my hardibacker or cement board all the way up to the sheetrock or should I remove that 7 in of sheetrock and have the cement board go all the way to the ceiling.
There’s no problem with going up to the sheetrock. As long as you have backer board and waterproofing up to the shower head then you should be fine.
D. Rodgers says
Great discussions…experimented with Hydro Ban and Kerdi,..built a box of out of Kerdi with Kerdi Fix and another one out of Kerdi using Kerdi Fix-but coated second box inside with Hydro Ban…neither box leaked, at all…this experiment lasted 2 months, Never saw moisture wicking. Seams were well sealed in both boxes, to wit, no leaks. As the HB bonded so well to the felt on Kerdi, there was no way to get water between layers on second box; tore them apart to find out after next experiment of punching holes in boxes…inserting pipes…Kerdi Fix to seal box one around pipe, Box 2 got HB around the pipe to Kerdi Board. Again, allowing for proper drying time of both…filled boxes above pipes (yes they were capped) –no leaks. Awesome products when you follow manufacture layup and curing times…actually I allowed 24 more hours than HB requires for flood testing since I had read others had issues trying to do the flood test too soon. All this was done because I wanted to know what was going on with bonding and waterproofing on the felt coated foam boards and have confidence I could get plane transitions sealed without having to worry about leaks or moisture sandwich. Also will add…tearing the boxes apart was not easy, Kerdi Fix is resilient. Pulling the HydroBan from the felt was a non-starter…could get it to separate…ultimately cut holes through Box 2, a lot of holes to look for moisture intrusion…nothing noted. So, success in experiment, success in building a shower…no leaks… have access via panels on all sides, and no indication of moisture. Also, looked with IR system that can be used on cell phones (great little tools) for leak indications…none. Grouting…painful as I used Spectra Lock 2…great stuff…but learned to clean it rapidly or there is a lot of haze that won’t come off. At any rate, you have a great forum and I won’t use anything but Kerdi or Hydro Ban, or/and combination of the two for next shower. Next experiment–wood box with Kerdi Board screwed to framing, then Hydro Ban the screw/washers…want to see if they can be waterproofed vice the painful material/felt coverage required by Schluter…just want to know. I know, warranty issue…not an issue for me, might be for others. Hence not recommending anything, just letting you know what you inspired me to try/learn/ultimately use. Cheers
Good feedback! It’s very helpful to know a products limits when you are using it. This is something that comes through experimentation and experience.
Thanks for sharing!
I know that drywall can be used with adhesive. I was considering doing the same with cement board but I understand that silicone and construction adhesives don’t like to adhere to it. Can I comb a thin layer of modified thinset onto studs/blocking before the CBU goes on to give it more holding power and fill any unevenness in the mounting surface? I’ve seen this recommended for foam board but not cement.
You could try. The reason that it works as well as it does with foam boards is because of the weight of them. It’s relatively easy to keep them in place while things dry.
Cement board needs more fasteners and has gravity affecting it moreso than foam so I’m not sure how well it would work.
But, in theory, it could work, I think. ?♂️
Melissa Vidales says
Have you used this material?
https:// www. tritonwatertight.com/products/triton-watertight-board/
No, it’s the first I’ve seen of that product. I’ve seen their regular backer board at a distributor but have no experience with it. Do you have any experience with the waterproof board?
Ryan Boggs says
So I have a quick question. I am using Kerdi Board on the walls. The floor is a concrete slab with the drain already installed. The slab is already slopped to the drain. Do I need to waterproof the concrete itself? I was thinking of using the Kerdi Membrane up the wall about 8 inches and sealing it to the concrete. Would this be sufficient? Or should I membrane the entire concrete floor?
A question about supporting the edges of cement board. I know we had the weeble vs wobble discussion but this is more specific. The wall along the long edge of the tub has a window so the studs are spaced 12″-17″-17″-12″. There’s a horizontal 2×4 between the center 3 studs ~2 feet up from the tub rim and the window framing higher up. How bad an idea is it not to have horizontal blocking just above the tub rim or behind the horizontal seam between the panels on that wall? The CBU will overlap the tub flange. I’ve got blocking above the tub flange and where I expect the seams to be on the other walls but this one has insulation in it so it’s a pain.
I’ll probably end up adding it in anyway but it may need to be thinner so I don’t disrupt the insulation as much. Would something like a 1×2 be enough?
I don’t think blocking between the seams on cement board is as big of a deal but I think it’s important block the perimeter of the tub.
A lot of times, if there are pipes and whatever in the stud bays, a 2×4 wont fit in between the studs all the way across.
In this case, I will notch the 2x out or fit a strip of plywood in between and attached to 2x2s, or something, on each end.
It just has to help support and isn’t structural so it doesn’t have to be 2x material.
Cindy Drozda says
You didn’t mention Dens Shield. It looks like a similar product to Wedi and Kerdi board, being a foam board with a waterproof membrane attached. It is a lot less cost than Kerdi board. What do you think of Dens Shield under tile on shower walls and under/behind tile for a kitchen counter?
DensShield is paperless gypsum with a waterproof coating so what’s above about sheetrock with a membrane over it is relevant. The edges are not tapered and you still have to seal the seams with something.
It’s fine for behind a kitchen counter but I’m not crazy about it beint used in showers.
The big difference between Denshield vs foam boards is that Denshield is made out of a water resistant gypsum and not waterproof polystyrene foam.
If you do decide to use it for a shower make sure you waterproof the seams and penetrations according to the instructions. Even better, install Kerdi over it.
Didn’t see your reply at first. Thank you and your right!
A question about using adhesive to attach cement board to studs. From looking around forums and such, my impression was “adhesive won’t stick to cement board.” I’m using adhesive to hang drywall for more holding power and to fill irregularities but I wasn’t planning on using anything with the cement board for that reason. Then I’m looking through Myron Ferguson’s (That Drywall Guy) drywall book and he suggests using adhesive when hanging cement board. I check the instruction sheet for some construction adhesive (liquid nails heavy duty) and it lists cement board as one of the “recommended for” materials. Any reason this isn’t done? It would be pointless if the waterproofing was plastic sheeting behind the CBU but if it’s a membrane on the outside, it should bond. Should help fill any uneven spots and make for an overall sturdier construction.
The adhesive that dries hard, like the liquid nails product, will definitely stick to cement board and could be a little bit useful.
It will fill in between the stud and the board.
I don’t know that it will hold cement board on the wall but if it was screwed in a couple of spots that should hold it until it dries.
Also, the adhesive shouldn’t take the place of fasteners or allow less fasteners.
But if you want to put some construction adhesive on the studs I certainly don’t think it will hurt anything.
However, this is an opinion and you should always check the manufacturer instructions and all that other stuff. ?
I would use the same number of screws.
I only found two pro-“adhesive with CBU” opinions so far. Ferguson’s may just be out of consistency with his drywall methods. The other one was that cement is brittle, putting screws through it creates stress points, which may cause cracking, and using adhesive helps distribute the load. That sounds like it wouldn’t have that strong an effect but probably doesn’t hurt.
It does seem like the adhesive would create a connection between the board and any backing like studs or blocking where it may not normally connect like if they were uneven or set back. That plus any extra holding power and adhesion over a wide surface instead of at some number of points would make for a more stable substrate. Does that sound reasonable?
Sorry for the late response but, yes, it seems reasonable to me.
I don’t see how adding adhesive could have a negative affect if the screw schedule is still honored.
Does cement board need to be dried or acclimatized like plywood? If I leave it in the back of a truck overnight covered by a tarp is the extra moisture it picks up going to be a problem during the install? I’m buying a bunch of sheets at once from a supply place that keeps them indoors. If I’m not done with them all in one day, do I have to bring them indoors? It’s supposed to be clear and 60 deg that night but it’s been pretty humid here and it’d probably absorb some moisture. It will probably be a few days at least before I’m done finishing the seams and move on to RedGard application.
You’re fine. A little moisture won’t hurt things and it won’t affect the installation of it.
Ok, thank you.
Is it worth pre-drilling pilot holes for the screws in 1/2″ permabase? Some of the pieces are going to be pretty narrow.
If you find an edge where you can’t get the screw in without it crumbling then I suppose it would be a good idea.
But Permabase is a good product and it would be unusual to have to pre drill.
I asked about this before but now the shimming is done and I’m about to put up the cement board. The studs are out of plane and bowed AND I needed to space out the wallboard by ~1/2″ to clear the tub flange. I sistered most of the studs but one wall is exterior and I needed the space for insulation (plus other space constraints, plus it’s hard to find an actually straight 2×3 to use as a sister) so a lot of the studs are shimmed. The shims are carved from 2-by’s and vary in width from less than 1/2″ to over 1″. They are glued with construction adhesive and screwed to the wall every 7-14″. A few had to be fine-tuned with drywall shims: the shims go between the studs and shim and are also laminated in place with the same construction adhesive. One wall is all shims: The stud spacing is 15″ on average, there’s some cross-blocking between them and a window frame in the middle. Another wall is mainly shims but is mostly drywall.
Does this sound like an acceptable approach? Shimming with plywood wasn’t really an option since the studs are out of whack and the shims needed to vary in thickness. I ended up carving them on a table saw. This seemed like a similar thing to hanging drywall on the ceiling with 1-by furring strips. The 1/2″ drywall was hung with 1-1/4″ screws and drywall adhesive and seems pretty solid. Are 1-1/4″ cement board screws sufficient for the permabase over the furring or do I need to use something that would go all the way through the shims and grab 5/8″ of the stud behind it? This would be pretty tough to set up since each stud varies in thickness drastically along its length.
Yes, I think it sounds like a good way of doing it. It sounds like you’ve put a lot of work into straightening up walls that weren’t ready for tile.
I’ve had to do some unorthodox blocking and shimming in condominiums before and sometimes it’s just the way it goes.
Personally, I would feel a little bit better having screws go through the shim into the framing. That doesn’t mean that it’s required or anything. They make 2.5 inch cement board screws but even the much more common 1 5/8 would probably work.
That being said, if the shims are glued to the studs then 1 1/4 are probably fine. If you’re trying to get it done this weekend and that’s what you have then you should be ok.
If there’s a problem spot that you’re not so sure about then you could always put a longer screw in at another time but at least you can get the hard part of hanging and cutting the board over with.
Thanks for the fast reply.
I went back and measured the furring: it varies from 1/2″ to 7/8″. Rock-on says to penetrate studs by an inch. PermaBase says 3/4″. So I need 2-1/8″ to 1-3/4″ screws for PermaBase’s requirement. The 2-1/4″ rock-ons didn’t seem that unreasonable so I decided to play it safe and go with those on shimmed studs. Already put up one 3×5 sheet: 1-1/4 into blocking and 2-1/4 through the furring (with adhesive). I had the thought that I could replace 1-1/4″ screws with the longer ones later too but ended up just going for it.
Is there a downside to using screws that are too long? Do they pop like drywall screws? I was worried they would split the furring or the studs so I pre-drilled everything but there was still a lot of squealing going in. Unfortunately, the rock-ons don’t have that cutting channel at the tip like a lot of the nicer decking screws.
I don’t know of a down side to longer screws. They just need to be a length to get into the stud.
Predrilling to prevent splitting the shims was a good idea. The Rock-on screws are the best for cement board, in my opinion.
Had a big sheet to put up so tried not pre-drilling to save time so the adhesive wouldn’t dry up prematurely. Getting the screws to go in straight (or at all) was a huge pain and once I switched back to pre-drilling part way through it started going faster. The T25 bit was probably crappy. I think I got it in time but it seemed like the screws might’ve actually been lifting the CBU off the studs because they don’t start into the wood right away. Do the rock-on’s pull the CBU tight again the wood as you force them flush like drywall screws? Seemed like they don’t strip through the CBU and i’ts like trying to screw 2 wood planks together.
When I’ve had cement board lifting off of the stud it’s usually been when I’m unintentionally trying to screw into a plumber nail plate.
I wonder if it’s separating the shim from the stud? That would cause lifting, I would think.
But there has been a few times when the screw hadn’t pulled the board all of the way in. I’ve caught it when putting a straight edge on it and just tapped the board in tight and finished driving the screw. But it’s not usual.
What are you using to drive the screws? I find an impact driver works great but that may not be a tool that you have at your disposal.
I’m using a cordless drill but it should be more than powerful enough. I usually have to set the clutch carefully so it doesn’t pull the screws all the way through the CBU. It’s not the shim pulling off because these were sistered studs and blocking. No metal plates and I mapped out where any screws were to avoid them. If it does lift, it’s a very small amount like 1/32 to 1/16. I think I can spot it if I look from the top b/w the board and blocking. Also if I’m driving the screw, see the CBU lift a bit but then it doesn’t drop back down.
The adhesive should hold it steady once it dries so it’s probably not the end of the world but I was a bit disappointed that (or if) it’s happening.
Sometimes the screws will hold it out and I usually just hammer those spots down and continue to sink the screw.
But I’ve never had it be an issue with every screw. Could be the impact driver is an advantage in this regard but I’m not sure.
Do you mean actually hammer it down with a hammer or just pound it down with your palm or something? Do you think it’s a significant issue if it is held off slightly? I don’t think I can hammer it down since the adhesive has set but it’s probably also filling that gap at least partially. It probably didn’t happen with every screw.
As a side-note, I dry-fitted every piece and from playing around with the CBU with and without the adhesive behind it, there are two advantages to having the adhesive (aside from the extra holding power, gap filling and all that happy horse-stuff):
– The adhesive keeps the CBU on the wall if the lower edge is resting on something. I wouldn’t leave it there but you can definitely let go for a moment or keep it in place with one finger.
– If you do have to shift it sideways for a small tweak, it’s easier to slide the panel with the adhesive.
Dan Quint says
Hi there…great site.
I have a project on the go and need some technical advice.
I am applying 12×24 tiles on top of MAPEGAURD UM.
The MAPEGAURD UM is going on top of a plywood substrate.
Can you suggest the best thinset to use between plywood and MAPEGAURD UM ?
What thinset to use to set tiles on top of the MAPEGAURD?
I do have some Kerabont T.
Thanks so much!
Good feedback on the adhesive!
Hammering down would be hard enough to knock it in without puncturing it. Hammering on a 2×4 block would be a better idea.
Wow!! Such a sweet site, thanks for all your time :)
So in my project im using a cement board of sorts which will run down to an existing cement curb/floor (basement) 2 walls are framed and 2 are curb. I will be installing a “disposable” cedar slat floor over the floor and was wondering how tight to run the cement board in both the wall corners and the pan (floor) junction? Can i just redgard the existing floor and curb? Could i build up a corner from floor to panel using mesh and thinset then redgard everything?
Thanks a bunch!!
The issue that you are going to run into is how to tie the waterproofing into the drain. Typically there should be a tileable 3-piece clamping shower drain installed. Or possibly a two-piece cast iron drain. I’m guessing that you have a normal basement drain though?
But, yes, Redgard over cement board and sloping shower pan are fine. I would put some waterproof fabric in the corner of the cement board and shower pan or at least some alkaline resistant mesh tape and thinset it in prior to waterproofing.
For creating a slope, I think your best bet would be to use some of Mapei’s Planipatch, or similar product, over the floor for sloping. I suggest Planipatch because it’s a good product, can be used in wet areas, and widely available (Lowes, for example). Other stores may have other brands.
For gapping the corners, different manufacturer’s say different things. Some say the gap should be lightly butted together and others want 1/8 inch gaps. No matter what you don’t want tight gaps that are under pressure.
Perfect, thanks for your time!
I will use hardie backer board and got their specs online… it is an existing raw concrete shower floor with the worst slope/pan/drain setup ive seen but it will drain and quickly lol hence the cedar slat floor to avoid cutting it all up.
Sweet website, i think you’ve saved alot of people alot of headache
What are your thoughts on Zip Board? It’s an engineered plywood sheathing?
Hi! Thank you for all of this information!
My husband and I are planning on using an ARC shower pan (also called Transolid Tuff Form) to create a curbless shower. It will be placed about 3 inches away from the walls of a corner (on top of reinforced joists), extending the slope to the walls with dry-pack mortar. We want to use Kerdi-board for the walls of the shower, transitioning to dry-wall for the parts of the bathroom that will not get wet. We also plan on using the Ditra heat system for heated floors outside the shower. We will be using 18x 18″ porcelain tiles for the shower walls, and continuing throughout the bathroom (just half way up the wall outside the shower area).
I have two questions:
1.) Which waterproofing system would you recommend for transitioning between the ARC system shower pan to the Kerdi system walls and floors (realizing that neither manufacturer will provide guarantee)?
2.) Modified thinset is recommended for installing large format tiles (LFT). However, Schluter recommends unmodified thinset with their products, even for LFTs. If unmodified thinset is used for installation on the Kerdi-board walls, should we switch to modified thinset when transitioning to the dry-wall?
Any warnings/suggestions about the whole plan would also be welcomed.
I never heard of Zip board and don’t know anything about it. What application are you looking to use it with?
1. I feel most of the waterproofing systems on the market perform very similarly to each other. So it’s about which one that you have available to you.
If you can find someone that will see a sheet membrane by the foot then that’s the one I would probably go with.
You’ll need to cover the seam between the shower pan and Ditra Heat at least 12 inches on each side.
Then you can cut strips of it to flash the corner seams. So you definitely don’t need a full roll.
All things being equal, I would probably get Kerdi because you’ll be using it with Schluter products.
As for thinset, I think there’s too much made of modified vs unmodified. However, if using an unmodified is what you want to do. I recommend either Ditraset (bostik) or Kerabond T (Mapei) for large format tiles.
Schluter also makes mortar now and one of their would work fine too.
Thank you so much for your quick and helpful response! I’ll let you know what we decide.
All the waterproofing bath and shower products are overkill. I’ve been setting tile for over 30 years and I’ve done… and redone.. four of my own showers in three of the four houses I’ve owned in that time span and only used wonder board and hardy board with no vapor barrier and no top membrane. I’ve never had a leak or any mold or moisture behind the walls of any of my own showers I’ve redone. The last shower I redid was last summer, he shower in our master bath… which I first did when we bought the house in 2000, so 18 years ago. The studs and wall cavity were as dry as a bone when I ripped out the old tile and wonder board. The mud pan, which only had membrane underneath one slope bed, was just as dry. There was zero water damage or mold in the other two showers I redid in my other homes. when I ripped them out. the industry has fooled a lot of smart people into spending a lot of money for nothing. Sitting/standing water is where the problem is. The amount of water that seeps through the tile and grout and backer-board of a shower wall is minuscule. The ONLY area a topical waterproof membrane makes any sense is installed over a sloped mud pan, run up the wall a few inches and wrapped over the shower damn/step. Anything more you’re giving you’re wasting your money.
You’re not the only one with this opinion and just because a shower doesn’t have a waterproofing membrane doesn’t guarantee it will fail. But many people want a better product and are happy to spend the money for it.
Dave Kalemba says
Hi DIYTileGuy: Like many here many thanks for your postings and advise. Very helpful. I am completing a shower stall and would like to use the Wedi board, but my glass guy is concerned about using a foam product behind the tile where the glass door will hang. The door will weigh up to 80lbs, and have three hinge points, and my glass guys thinks the foam will not support the weight. He suggests running a strip of cement backer board in just the area where the hings will attach, but I’m guessing the two products are not compatible (i.e., movement, expansion, even thickness perhaps). Thanks for your comments….
The best way of doing it is to install wood framing, or backing, for the hinges and other attachment points to screw into. If you do it this way then Wedi board or any other backer board is just fine.
Napua Asing says
Condo built 1973. Need to demo and replace with above ground rough tub. What’s best product to use for: Framing, mold & water resistant backer board, and shower wall? Please help?
My personal preference is for one of the foam backer board products but many of the options covered in this post that incorporate a waterproof later are good choices.
My tile installer is going to use acqua board for drywall in the tub wall area. Can you please provide information on this material compared to other materials e.g. glass mat gypsum, i.e. Dens Shield?
Thanks a lot!
I’ve never heard of aqua board but if it’s a glass mat gypsum the installer will need to make sure the seams and edges are waterproofed correctly.
Usually, that’s with either a sealant or a liquid waterproofing membrane. But I’m not sure how aqua board wants it done.
Alan Fairweather says
Here’s an odd tiling question… I am installing a basement bathroom in my daughter’s 10 year old house. We have moved the toilet and shower rough-in location to better align the room. Unfortunately the builder put two floor clean-outs directly in front of the only access door to the bathroom. The depression is about a foot long and six inches wide and slopes from grade to about two inches deep at the two clean-outs,. I showed her the brass clean-out cover that I could install over the clean-outs before I lay the tile. She wants nothing to do with metal plates ruining her beautiful fancy tile floor. They spoke with a plumber friend of theirs who said if it was his home he’d just note the location then cement over the recess and tile over it all reserving extra tile in case they ever needed access. My thought is that if access were ever required it would be a pain to break up the concrete. I thought of two solutions and would be interested in your suggestions. What if I filled the sloped depression where the clean-outs are with Saran Wrap then filled with concrete. That should make the piece removable after the section of tile was broken up. My alternate solution would be to fill the depression with dense foam insulation spray and precision shave it to grade before tiling. We will be using 10×10 porcelain tile.
They should stay open and accessible. If the cuts around them are done well then they can actually be a feature, or sorts.
If you are going to cover them then my preference would be for plastic wrap and then mortar the tiles in. The problem is that the next homeowner may not know the system and understand where the cleanouts are.
Great article. I’ve used Hardieboard a lot over the years for various applications. The dust is very dangerous to breath (I’m an OSHA instructor also). The best thing I’ve found over the years to cut this is a handheld circular wet saw. It’s a bit messy with the water but provides for very nice and more exact cuts and no dust.
I think Hardibacker shears probably create the least amount of dust but they don’t cut a real clean edge. Maybe there’s been advancements in these in the last few years?
But cutting with water, like you describe, would be a good method also. That dust is dangerous stuff!
Roger North Texas says
Great article. I just finished updating a guest bathroom. I was able to find Durock foam board that I used for the backer. It was so easy to install, especially for one person. I found that I had to rebuild some of the studs to meet the spacing and bracing requirements, plus even out various bulges and dips in the studs as the foam board is not so forgiving as a more rigid product in that respect. Also, the Durock product was about half the price of a Kerdi foam board.
Now that the shower/tub enclosure is complete, I’m finding that the Durock panels have an added bonus of providing more insulation in the walls, so the entire bathroom can be warmed up quickly when the weather is cold. Very cozy.
Thanks for the great website.
Good feedback! I tried out Durock foam board and was pleasantly surprised by it. It seems like a nice product.
Really good article. We had our contractor take out greenboard that they had installed as the backer for our soon to be completed remodeled shower. We are going to have them install the Hardiebacker instead, thanks to this article and I’m sure we’ll be happy with it.
I do have a question though: Our contractor is planning to install a plastic vapor barrier between the studs and Hardiebacker, and then before installing the tile on the shower walls, they are planning to paint Aquadefense onto the Hardiebacker. The vapor barrier will is only planned to be installed on the one wall of the shower that is an exterior wall of the home. The other two walls of the shower will have the Aquadefense but not the vapor barrier. We are wondering if it is a good idea to have both the vapor barrier and the Aquadefense on that exterior wall on the different sides of the Hardiebacker. We’d love to get your thoughts. And fast! The are coming tomorrow! Thanks!
The application of the vapor barrier in your contractor’s application has nothing to do with shower moisture and has to do with the building envelope and exterior moisture management. That’s not something that I will pretend to know about so hopefully your contractor does. You could try contacting the Hardibacker people and see if they have information on that particular application.
Thanks for being honest. I appreciate it. I called them prior to making this post and they said that their product required no water proofing whatsoever, which just doesn’t seem like a good idea.
That’s funny because they just came out with a new version of their 1/2 inch Hardibacker that is now “waterproof.” I wonder why they would need that?
Art Gillman says
Hi, I’m wondering about the USG Durock ultralight backer board. In the instructions, all of the screw heads are sealed with Durock sealant, which does not seem to stick to thinset. If there are screws every 6-8 inches and the heads are sealed with a diameter of a few inches of sealant, doesn’t this weaken the strength of the bond to the tiles? In some videos, it looks like half the wall is sealant. Looks like a potential disaster if big tiles don’t have enough bond strength.
I’ve asked about this in the past and the manufacturer’s don’t seem to think this is an issue. I’d like to find out more but that’s what I know right now.
Here is an odd question. I just completed a Wedi board installation on a tub surround. I had to remove the pink wall insulation from the long wall and the plimbing wall, so I could plum some of the studs by installing sister studs. These are exterior walls. When I installed the Wedi on the walls, I put the insulation back into the long wall, but forgot the 32″ wide plumbing wall. So, how much am I risking if I leave it as is, considering I’m in So. California and no freezing issues. Yes, it gets hot in the summer, but I’m willing to stomach a few $$ in cooling cost vs having to rip the wall apart again. Would this be a problem from tile/wall durability standpoint?
Insulation isn’t required to tile the wall so there’s no danger from that standpoint. Obviously, it would be nice to have it in there though.
D square says
Great article and discussions. Something I haven’t seen – fire rating. My new bathroom is on a fire-rated wall with the garage on the other side. I have 6″ studs and 5/8 sheetrock on the garage side. Are any of these products fire-rated (meeting San Francisco code – if you know…)
I’m hoping that I won’t have to cover 5/8 sheetrock with tile backer, that I’ll be able to just use the tile backer on the studs to form the fire-rated wall.
This is something where you’ll have to check with San Francisco’s codes for what they require.
I know GoBoard will have the top for rating of the foam boards but I still don’t know if that will be high enough for what you need.
You could always go with 5/8 drywall or Deshield then cover that with Kerdi fabric. It’s not ideal but may be a consideration considering your circumstances.
This is a great article. Thanks so much! We are retiling our steam shower. My contractor gave me a quote between using kerdi and wedi – with wedi being more expensive. I guess my question would be is wedi better than kerdi for a steam shower? Thanks!
Either one is suitable for a residential steam shower. However, Wedi should have a vapor coating if it’s to be installed in this application. Make sure that your contractor will be applying that. Steam showers aren’t something to take lightly.
Thanks so much. Do I need this vapor barrier coating for kerdi? My contractor doesn’t seem to believe we need this vapor barrier for wedi for some reason. He’s already charging me $600 more to install wedi over kerdi. Much appreciate your help.
No, Kerdi is a good enough vapor barrier for a residential steam shower. I’m referring to Kerdi sheet membrane and not Kerdi-board.
As far as charging additional, I’ll leave that up to you guys but Wedi will save labor vs Kerdi and backerboard. So the materials are a little more but it’s a little easier going.
Erica Eschenbacher says
Need your advice on best method for sloped tile ceiling that is vaporproof. Building a steam shower after many months of research. Originally was going to use Durock cement board covered in Nobleseal membrane for Vaporproofing. While choosing tile, hubby discovered usg durock ultralight, thinking extra cost so worth the weight, especially for tiled ceiling. ( Which in steam shower absolutely necessary) get home with product and research manufacturer information to find us ultralight already vaporproofed!! Yeah! But then cannot find any references to installation on ceiling, in fact I may have read somewhere not to use on ceiling. I e mailed manufacturer with no response. Will be using Durock waterproofing membrane fabric on floors, thinking maybe have to use heavy cement board, plus membrane to vaporsheild cieling? Would really like to stay with one brand of waterproofing ( did not choose schluter, 2x2hex tiles too small on floor and cieling). Any assistance would be much appreciated. Your post is nicely done, especially after months of reading so many other conflicting @#$& measuring contests. I really like your style! Thanks, Erica
I think your concerns about Durock Ultralight Foam Tile Backerboard on the ceiling is not if it’s vapor-proof enough but if the fasteners will hold it properly? Because it certainly appears to have the vapor qualifications and if it’s OK for walls then it’s OK for ceilings.
As far as fastening, I can’t find any information on their site about fastening Durock foam board to ceilings and if the cement board screws would have enough holding power. I found their site and information to be frustrating.
However, I did look at a competitors product (Hydroban Board) and their instructions for ceilings (they have good instructions) require 16-inch maximum joist spacing and TAB WASHERS with 1 5/8 screws fastened at a maximum spacing of 6-inches. Tab washers are what are used for Wedi and Kerdi-board.
So I can’t direct you to what USG wants for their foam board but maybe the instructions for HydroBan Board are helpful for reference purposes.
Thanks for your comments about this post.
Larry Farnsworth says
I am replacing a fiberglass shower with a tile one and hiring a guy to build my shower pan . I plan to use Duroc cement board on the walls. Can you really build a mud pan without a liner an d simply use Aqua Defence applied to the pan andDuroc and be waterproof?
This is a new concept to me. Should I look for someone to build a traditional pan or use a Tile Redi pan? Thanks for your advice.
It’s possible. It depends on how it’s tied into the drain. A lot of guys in this scenario will do a “divot” around the drain or use a Kerdi drain. The waterproofing would need to extend up the walls to the shower head.
However, I would caution you with this method. I’m not a big fan of shower pans built with liquid waterproofing. There’s too much room for human error in my opinion. If you want to do one then I recommend two things: waterproof fabric in all seams, around the drain, and in the corners. Then do a flood test on the shower pan to make sure it works prior to tiling.
A flood test is where the drain is plugged then the shower is filled with water and allowed to sit for 24-72 hours. If the water leaks then it doesn’t work right. If the waterproofing bubbles up then it isn’t working correctly.
If you want to do a paint-on waterproofing then I’d encourage you to use something like Redgard Speedcoat, Hydroban Quick Cure, or Ardex 8+9. I’ve never used these products but trust them more than the water-based versions. I don’t know if Mapei has a urethane version of Aquadefense or not.
Solid article, and great site in general. I wish it was a requirement for all tile installers to read this information before starting work. What are your thoughts on Glass Mat Gypsum Wall Board with the Kerdi shower system over the top? I am thinking Kerdi shower system over cement board is the way to go (per your article), but cement board is a beast for the DIYer. Thank for your advice!
Terry Haley says
I have found that using the torx deck screws is the best.
It’s fine. Schluter has approved that as a substrate and it’s better than drywall.
Yes, thank you for your reply. They do have Torx cement board screws now and they work much better than the Philips version.
I have been reading through the comments and am overwhelmed. I have a ‘simple’ question. We just experience a showed leak and everything behind the showed – b ackerboard to studs – was wet, including the insulation. Has been wet for at least 4-6 weeks. Is it sufficient to dry it out without replacing everything – tiles, backerboard, etc?
Yes, you can simply dry the shower out but I don’t understand how that solves anything unless you never use the shower again? If the leak was caused by a pipe, the pipe was fixed, and it was fixed in a manner that required no damage to the shower then I suppose drying the shower out and using it again in the future would be OK.
But if the leak is because of a faulty or failing installation- quite common- then you’ll have to fix the problem.
Thank you. Yes, fixed the source of the leak. But is drying it out sufficient to eliminate any mold that might have grown either in the studs or backerboard?
Drying it out is a good idea but if there is real mold on the studs then that should be removed according to best practices.
Such a great helpful site. Thank you for your time to help us diy types! Few questions if I may (often over think things so….).
Using USG Foam Board. They have their own sealant & membrane band (which looks like the surface material of the boards & specify to apply with unmodified). Oh boy, just found another set install instructions USG website which state can use modified as well for the band & setting tiles ( Tile-setting mortar should meet ANSI A118.1, A118.4, A118.11 or A118.15) not just unmodified as required in their other set instructions. This actually make life easier as hard find good unmodified & have heard of adhesion issues. I’ve watched your GoBoard install video numerous times & like your approach. especially sealing board to tub. Here is question & my assumption. Installing the boards they do not require/mention any sealant between boards or bottom to top tub. Once up just seal fasteners with the sealant & the seams with the membrane band & thinset. Do you see any issue if I put bead of sealant between each board & top tub as install? Belt & suspenders approach. & probably not necessary but if not cause any issues make me feel better with the extra waterproofing. My concern would be the thinset required to place the membrane might not stick. However, my assumption is that since their sealant is used over top of the fastener penetrations that bonding to the future required thinset should not be a problem as that what specified/needed set the tiles.. Do you think that a safe assumption the sealant between boards won’t cause adhesion issues with setting the band ?
Another question. The tub stated certain type screws & heads so complied. In some places the heads are almost flush with the inside tub board surface as smaller screw heads kept stripping out requiring use of next larger size).. Laying straight edge vertical on board the screw heads in a few places are just barely behind (none touch) the straight edge. Is there a recommended setback of screw heads to not cause sealing issues?
The big question as I always concerned about water penetrations especially at tub junction ! I like your board/tub joint fill using sealant & the mesh tape. I’ve watched Schluter install videos & how they bring their tape band down seal board to tub using kerdi fix sealant at junction then thinset above & embed the band into both.. No specific instructions by USG in this area other than seams use the waterproofing membrane band which is set with thinset. Do you have a personal opinion on which method should use Schluter is another variation not in your 3 ways? Also, my tub has a very specific list of sealants appropriate to use on the tub or warranty voided, Yet say follow manufacturer instructions on finishing to tub. Just love how warranties basically worthless & so many ways point fingers somewhere else. Thoughts? Maybe use your sealant/mesh method & then embed the band into all that (but that starts building things up quite abit. Yet, having sealant both surfaces & mesh embeded seems much stronger than just the band adhered with sealant & thinset so that takes me back to your method..
Lastly, when bringing foam board to end outside tub wet zone is there a minimum distance should consider? I know do want it past tub edge! My tub is curved so was thinking ending tile about even with the widest point tub (about 4.5″ out from wall end edges of tub. Will be using shower curtain. I need to get the drywall up in that room & do know can extend tile onto the drywall with no issues. Need balance wet zone preventive measures against not wanting take foam board out too far requiring me to use tile past aesthetically pleasing/logical line. Opinion appreciated!
Thanks so much for the simple logic I’m sure you will impart to this overthinker. Answers will help the other bath will do next so hopefully this will get all my questions.
You can use sealant in between the seams and then use the 5-inch banding over that. There’s nothing wrong with doing that. Also, the Schluter video that shows the banding around the edge of the tub is a good method and would be a good way to finish your tub with Durock foam board.
Additionally, there’s no minimum for bringing the board past the tub. Go as far as makes sense for your application. For the screws, all I can say is that the heads should be recessed enough that they don’t stick out but not so far that they penetrate the surface coating.
Hopefully, that helps.
So looks like I screwed up thinking green board was a good option for my tub/shower surround will be taking it down two questions for you
1) can I leave a layer of 1/2″ green board behind a layer of 1/2″ concrete board covered with red guard? It’s a fire wall so I double dry walled…
2) Over the concrete board before I red guard should I use regular drywall mud/tape or should I be using thinset will mesh tape (if so modified or unmodified) or something completely different
Enjoy your posts thanks in advance!
If you’ve already installed the green board then an easy option is to simply install Kerdi membrane over the top of it. But if you remove the green board then I would probably leave the inside layer because of the fire rating. Then install cement board, tape and mud the seams, then Redgard over that.
Al Rouse says
Great thread of advice. The best. Consistent with all that I’ve worked with and what I want to know.
Excellent advice here. Much appreciated, thank you. Given all I’ve learned here, this is what I plan to do.
45in. x 82in. shower area with single slope from entry/towel area down to a liner drain at the shower end. I have sloped the sub floor (23/32 t&g osb on 2x12s 16 in. on center running length wise). On this I would screw down 1/4 backer board, tape the seams and thinset 1/2 go board (1/4 is not available in my big box store). JM rep wants me to screw the goboard down but I’d rather not have all those screw holes in the base. They say I can thinset it to concrete,, no fasteners required)
36in. of the towel end will have radiant heat mat and the shower end will have ditra to be even with the heat mat/wires.
Goboard base will be sealed and taped to the goboard walls.
Is this sound thinking or do you see problems?
What would be the best backer board to use for tiling
The wall “above the tub surround.” I’m remodeling my bath, but not installing a new shower, just adding tile to the wall
Thanks for any info
Sounds OK to me but I think it should be fastened to the plywood along with thinset. I don’t know what the hesitation would be in doing so? I think you are asking for trouble if you want the thinset mortar to do all the work.
You can use whatever you like. Even drywall is fine as long as you are above the shower head.
Thank you for the reply.
I’m reluctant to screw the goboard floor (base) down because schluder, Widi, USG,etal. aren’t screwing their shower bases down, just thinset over the subfloor. I thought screwing a 1/4 ” fiber cement backer over the subfloor would give a base similar to concrete for good adherence. The goboard on the walls would be screwed up and the screws sealed as usual.
Just wondering why the other foam bases aren’t being screwed down? I probably think too much.
I suppose so. I guess it’s about how much support is under the sloped plywood. If there’s adequate support then it probably won’t move too much and you’d be OK.
I am probably going to use Durock or Permabase cement board under mu remodeled shower.
I haveinsulated all the walls except the one with all the plumbing with polysio , 2″.
Do I need to put some plastic on the plumbing wall or will the Durock with a paint on waterproofing be ok? My tile man is using mortar I believe.
My tile man wants to use Densshield but I do not want to use that since I have read all the comments and your recommendations.
He wants to use cement grout but I would prefer epoxy.
Durock with a waterproofing membrane will be fine. You’ll have to work it out with the installer about the grout. There may be a reason they don’t want to use epoxy but if your willing to pay for it I don’t know why you can’t get it?
Pam Everson says
Pam here again.
I forgot to mention that this is a STEAM shower that I am doing. Will the cement board with waterproofing membrane be suitable? How many coats? Or is it better to use a 3 dimensional membrane?
I would like to follow the requirements set out by the TCNA handbook . My contractor did not want to use cement board and insisted on the DensShield so we had to part ways.
I want to make sure the next contractor is going to do things correctly.
Thanks yo so much for your help and advice.
If you are doing a steam shower you’ll want to hire a competent contractor with experience in those installations.
They should have products that they want to use. Personally, I would not be comfortable with a liquid waterproofing membrane but there are some products that say they’re ok for that purpose.
Michelle Harper says
We have installed Propanel using Sikaflex(?) as instructed and are ready to finally tile. We are confused on what thinset mortar we can use. The company’s site says “A modified thinset is specified for tile setting. Mastic adhesive should never be used.” Can we use Mapei porcelain tile thinset mortar? (Polymer enriched thinset mortar) We just want this shower done, but don’t want to mess it up. Thanks!
That mortar will work fine.
Following your excellent video, can i put goboard over the existing wall board in the shower? Walls are plain ol’ 1/2″ drywall on 3mil poly vapor barrier over craftfaced fiberglass in an interior stud wall. They are painted and in very good shape. With the poly I fear making the dreaded “moisture sandwich” and loosing the integrity of what otherwise is a substantial base for the goboard. Or do I need to demo the walls and remove the poly?
While I think it would work OK to do this I don’t know what the official word is from the GoBoard people. You might try contacting them through their website or calling the tech line to get a more official answer.
Great site and information! I am renovating bathroom, entirely. As a woman, i am strong enough but drywall, fiberboard, etc daunt me because of the weight and size. I love the idea of foam board as I can handle it. It also provides an insulation. So the money i save not having to hire someone for the drywall installation alone is good. But my experience is ‘if it looks easy, there is a reason. Like all of us, i want to do it right the first time. thoughts?
I’m all for foam board and use it regularly in my own business. You might look at my GoBoard post if you have questions on how they are installed. Each brand has its own instructions but they do share similarities.
Kevin Bertram says
Appreciate all the great info.
I am getting ready to tile shower walls in an upstairs bathroom of a 1920 home. Outside siding is horizontal wood overlap.
It’s an old house and has its creaks and such.
I’m speaking with other tile guys my understanding is that a little bit of movement over time will be ok, but that cement board would provide the best backing because it’s more solid and provide “shear” support.
Would cement board be preferable in this situation as opposed to one of the other lightweight boards?
I don’t think it matters. There should only be so much movement and if it’s too much the tile and/or grout will start to crack.
I’m remodeling a bathrrom and trying to put a curbless shower and was looking at using the Kerdi System, however, I don’t see a shower pan in the correct size. Wedi has many more options and I think I can make one of theirs work in my space. I’m wondering if I can use a Wedi pan and the rest of the Kerdi system? Trying to work on a budget, but also willing to pay a bit extra for ease of install.
Also, one of the walls is exterior and we will be using Rockwool which requires a plastic vapor barrior. Do I need to me concerned about a ‘moisture sandwich’ if were to go with the standard hardibacker and liquid waterproofer?
I don’t recommend that you mix and match these two systems. The Kerdi facing is a bit different than the others and they have their own way they want you to treat the seams. I would stick with one or the other.
Wedi has thin pans that are made for curbless showers. If you are going over a wood subfloor then I would look into the “Ligno” line from Wedi.
Lastly, if you need the plastic vapor barrier then I would use it.
Dennis Carlson says
Wonderful website and blog….thank you. Having read it from top to bottom my questions relate to a remodel (down to studs) of two bathrooms.
Question 1: The walls above the shower pan and tub will be tiled (not a steam shower). I have Hardiboard on site, but not installed. I own a shearing tool. However, I’m willing to pay the premium for Wedi Board and have a local source. Is the Wedi board sufficiently superior to membrane treated Hardi to warrant changing materials? If not, what is your recommended membrane? I will be hanging the board directly to studs and shimming as needed. Waterproofing will rely on the membrane.
Question 2: Sheetrock was removed in the area of the tub and shower, but not completely from the bathroom. Is green board needed to butt up to the backer board (Wedi or Hardi)? I intend to lap it 2” under the tile at the sides and top (dry locations) per your blog instructions and use mesh tape. Is thinset the preferred compound vs all purpose “mud”?
Hardibacker vs Wedi board is a decision that you’ll have to decide for yourself. No matter which one that you use the end result will be that you have waterproof shower walls. How much does ease of installation and time matter vs price? Your time, skills, and money are what will go into that decision.
As far as the second question, if the sheetrock joint gets covered by tile then you’ll want thinset on that joint and not drywall compound.
John Fratangelo says
I have installed many showers and floors. In my opinion hardi backer is the best. I kept running into the same problem. So what I do is drill a pilot hole with I one eighth bit then countersink it a little with a half inch concrete bit( they last longer). Then screw away. So much easier. Hope this helps.
We are remodeling a small bathroom in the lower level of our house with a small shower. The exterior walls are half-cement foundation walls and half wood-framed (lower half is cement foundation & wood-frame sits on top). It has been very difficult to figure out how to appropriately insulate this type of wall (both components) and then hang drywall, especially considering we have space constraints. One option is to glue XPS foam insulation directly to the cement, then to install a 2×4 framed wall over that, then obviously hang drywall, etc. over that. But due to space constraints, I don’t think we’d use more than 1×3 furring strips over the XPS, then drywall, etc.. I see foam board tile backer is your preference for shower/tub enclosures and I see that several of the brands offer 2″ thick foam backer board, which got me thinking of how insulating the one exterior wall (half cement/half studs) in our shower. Could a thick foam tile backer board take the place of the XPS insulation on the outside concrete foundation wall for our very small shower? Rather than have 2″ XPS insulation over the cement, then 1″ furring strip, then attaching thin foam tile backer board to that…could we just kill two birds with one stone and use the thicker tile backer board to insulate and be the tile backer? Thank you for any advice you can offer. And if anyone has ideas for insulating half foundation walls (both components of it working together), that would be helpful as well, as it’s probably clear to everyone how confused I am.
I only know about foam as it relates to showers and waterproofing. As far as what’s ok to use for insulation is beyond my expertise.
I could even imagine trying to install any cement board with Phillips head screws. Even in my small guest bath, where I used Hardie on both the tub surround and the floor, I went through at least 4 torx bits
With an impact driver it goes fairly well. Torx is still a much better improvement though.
THANK YOU!! I am a woman/target for incompetent contractors and workers to pretend to know what they are doing and charge me lots of money for work that is actually dangerous. My bathroom has been gutted three times now! So I am finally checking for myself how things are done since so few people who should know really do. This advice has been the best I’ve found.
Thank you for this knowlegable forum!
I am building a steam shower. After reading your post I am thinking to go with Wedi or Durock.
Is one thinner than the other? My shower width is an issue. I’m also worried about the security of tiles on my celing esp. because I am in earthquake territory. Any advice? Also, I am planning to installl a bench.
Any suggestions on what material to make the bench with and how best to water proof?
Will any of those work for an RV shower?
I think Wedi is a great product. If you want to use Durock foam board you should know that it has been discontinued and will be reappearing later this year (2020) under a new label, not under the Durock name. So you may have trouble locating it. However, Durock cement board will continue to be widely available.
If you are building a steam shower you should know that a steam shower has it’s own requirements. Wedi now has a brand new wall panel board with increased vapor protection that is specifically designed for steam showers and I would recommend using it. It comes in 1/2 inch thickness which is pretty standard for shower walls.
They may have special fastening instructions for ceilings so you’ll have to check the instructions for those. By the way, a steam shower ceiling should have a 2-inch per foot slope to it. This is another of the special steam shower requirements.
For the bench, you can get one of Wedi’s specially designed benches, make one yourself out of their 2-inch foam panels, or frame one out of wood and cover it with their 1/2-inch building panels. It’s up to you.
Here’s a link to Wedi’s site and an affiliate link to Amazon that has some of their products that you can order.
I would think the lighter weight foam boards would be the way to go with an RV. You will need to make sure the minimum stud spacing is followed, however.
There is quite a bit of useful information here, but it doesn’t help me much because of regional supply issues. To the best of my knowledge, there are no suppliers of Schluter or Wedi within a hundred miles of me. Apart from the price, the drawback to foam board is that no one stocks it. I can special order it, but then I have to order at least 10 sheets. What I can get is Durock, Fiberock, Allura Fiber/Cement board, possibly HardieBacker and DensShield. I gathered that your low opinion of DensShield was because of improper or no waterproofing. If DensShield were properly waterproofed, would that make a difference in your opinion? Other than DensShield, all of the other products are only carried in 36″ X 60″ sheets, which results in a lot of waste if your studs are on 16″ centers and you put your joints on the studs. I have never given any thought to not putting the vertical joints on studs, is that even possible? I’m leaning toward Fiberock, because I’m just not a fan of Durock. In my area, the most commonly available waterproofing materials are Prova-Mat and TEC Hydraflex. I don’t see much reference to these products on the web, other than the manufacturer’s promos. One or the other is probably appropriate for my use. I’ve always wondered why a liquid membrane wasn’t used to bond the corners and bands over the mats. In so many of the Youtube videos that I have seen of installations with materials like Kerdi, the installer only laps the band about 1/2″ over the preformed corners, instead of 2″. I presume that this is to try to limit the buildup in the corners. Do you have any thoughts on these?
Fiberock is just fine. I don’t care for Denshield partly because it’s gypsum-based. However, if that’s what you want to use it is considered an appropriate product for what you want to do but make sure you treat the seams and penetrations properly. Additionally, TEC Hydraflex should be just fine for waterproofing. It appears it’s competitive with similar products and TEC is a respected manufacturer. Prova is also just fine. I don’t have great access to their products in my area so I don’t have familiarity with using them.
I’ve been doing tile for 22 years 2nd generation Kerdi Board is the best on the market hands down
Shelley christensen says
I agree completely and am experiencing the same issue with Hardie board and the screws. Very frustrating.
Jonathan Grossmann says
DIY tile guy,
I’m building my first shower from scratch and looking at the Prova Waterproofing system. It looks similar to Kerdi and I’m wondering if you have any experience with this product. I have a cement floor in the basement bathroom that I am working on and we are in the process of taking out the old fiberglass shower. I have an experienced local tile guy helping me with questions but he hasn’t used any of the newer products like kerdi board etc. Thanks for all of your information on the website. You are very helpful.
Thank you! Prova makes shower systems similar to Kerdi and Wedi and I have not installed their particular system. But some of the Kerdi system information should be helpful for either brand.
Jonathan Grossmann says
Thank you for all of your information on your well organized website.
Hi, not sure what you are actually finding negative re: Denshield. Your listed problem with it, screw holes and joints should be treated/sealed, is the same with all the other boards..
Besides ease and clean install, an advantage over cement board is that it has a waterproof face and core, no need to worry about water absorption or wicking.
You comment about not liking it because it is a gypsum product. But with my own long-term soak tests and numerous installs I can confidently attest to it being among the best options for showers and tubs surrounds.
I use sealant on seams and screws, kerdi band for corners, and schluter waterproofing for the plumbing openings, but I would treat all these boards the same way.
Thanks for your input and I appreciate the differing point of view. With so many backer board choices, Denshield is still at the bottom of my list. However, your comments may help readers that are considering it as an option.
I am building a large shower and have uneven drywall that has a plastic face..I wanted to cover it with hardie board to even everything out to a smooth consistancy..then I will use my kerdi board on top..as waterproof tileable surface..my question is since I have kerdi over all do I need to tape and seal the joint’s of the hardie backer..and does the kerdi need to have thinset to the hardie? Thanks for any clarification you can offer..
This sort of thing would be outside the scope of a normal installation and there aren’t really any guidelines for it. I’m guessing that you wouldn’t need to tape the seams on the cement board but it obviously wouldn’t hurt. And I would probably thinset the Kerdi board to the cement board but I’m not aware of any written instructions that would specify one way or another. You could always check with Schluter and see what they would recommend.
been using greenboard quite a bit, is the author saying it’s no longer OK? Putting a custom plastic sheet (very thick, about 3/16″ ) overlapping, with expandable adhesive.
It is a very useful article. I have a small question. I have 2nd floor 500 sq,ft. studio apartment on the top of my garage. I am planning to lay porcelain tiles, as I am tired of chaging carpets. I am concerned about weight. I am planning to use Foam backer boards and prolite thinset with 2′ x 1′ tiles.
Do you have any other suggestions to reduce the weight.
I don’t want to use Wood, laminate or Vinyl wood planks as the renting people are not going to maintain and make tonnes of scratches. Thank you in advance for an early reply to my e mail.
Hi! I was reading your tile substrate article and it was very informative, thank you! I”m considering doing my shower with the kerdi system, but also have the wall mounted toilet system on the other side of the bathroom. I know the manufacturer suggests green board, cement board, or tile backer board behind the area where the toilet will be mounted, and I”m wondering if you’ve used kerdi or one of the others behind a wall mounted toilet system yet, and what your experience was? Thanks so much!
This is a question not a comment except that the site appears well informed and organized.
I have a new construction build for a house and have 2 – tub surrounds and 1 walk in shower. All 3 of these have an exterior wall in which has the 6 mil poly vapor barrier installed with insulation as required for code. The walk in shower I am looking at using a mud pan along with the PVC liner from oatey following their install instructions. For the cement board I’m considering using the prova mat wall membrane (cause I have lots of this on hand) to install but I am confused as what to do for behind the cement board due to the exterior walls having poly vapor barrier installed and the sandwich effect discussed. The shower I plan on having the cement board about 1/2″ up from the pan to create a separation of wicking water and as you posted above gives a separation between the two membranes of PVC and waterproofing membrane.
Do you have a recommendation of what to do with the exterior walls with the poly vapor barrier installed and cannot be removed. The shower I would like to have as cement board but am open to changing the backer board on the tub surrounds that I would still be covering them with the prova mat membrane (again as I already have this membrane). opinions?
For weight, that’s about all that you can do. However, your floor will either support a tile installation or it won’t. So I would run your floor framing information through a deflection calculator and see if it will support a tile floor. If so, you don’t have to worry about weight if you don’t want to.
I have not installed Kerdi in that situation but I don’t see how it would be different. You can install backer board on that wall and Kerdi over it. The wall mount toilets that I’ve seen bolt to the studs and shouldn’t be an issue for something like a backer board. Hopefully, I’ve understood the question that you are asking.
I understand what you are asking and I don’t know if there is a good answer for it. My area of experience is with building showers and not with insulation and vapor management for exterior walls.
What I usually do is let the insulation people do their job and I do my job. But I’m not going to recommend slicing, or defeating, their barrier which some people would recommend. I just don’t know enough about it to recommend something like that. But I get asked this enough that I’d like to find a better answer.
appreciate the fast response and seems to be a long and confusing debate across the internet from what i see. I will probably end up furring the wall out to allow the air gap between the backer board and the exterior wall vapor barrier to allow this to breathe if water ever did get through although if waterproofed with the prova mat it should never see water. Appears to be a long and convoluted debate on the topic.
Installing shower in old house that has a small window in the back of shower so we will need a shower panel that is easy to cut. Ideally tile would work, but it is cod prohibitive with the labor.What do you recommend?
Foam is much easier to cut and cement board is more labor. GoBoard seems to be a happy medium
Thank you for all of the information in a way that is clear to read and understand! :)
Thank you! I’m glad that it’s helpful and appreciate the feedback!
I’ve removed some old tiles around my bath/shower area, and it has damaged some of the plasterboard behind it. Could I fix some 6mm foam backer board to the plasterboard (Wedi, Jackoboard etc) and tile over the top of this? Also would I be best fixing the foam boards to the wall with screws (into the studs where possible) or with adhesive too? Finally, what would be recommended to seal the joins and edges of the foam board?
It depends on the condition of the walls. They will have to be stiff enough to support tile. But I suppose you could install foam board over it. I’m not familiar with Jackoboard but Wedi would want you to use their washers and screws and use their sealant for all seams and penetrations.
I am redoing my bathroom and just want to make sure I’m doing the shower wall right….so first I have to level out the studs then put up the Hardi board. Second tape and coat the seams. Third, apply redgaurd. Last, apply thinset then tile and grout…does anything sound missing? Or am I good to go.
That sounds like a winning formula!
I am in the process of putting up a building for our kennel dogs. They currently live in our home but we would like to make space by giving them their own house (not the typical kennel). We want to waterproof the walls but also want to insulate it really well. What type of backer board would you recommend for us? Also I thought about putting up tile board for the surface layer. Thanks!
I think most of the tile backer boards listed in this post will work fine assuming they will be tiled over. If they are going to be outdoors then I think cement board would work the best. The waterproofing methods that I talk about in other posts assume interior installations being and tiled over.
I find Kerdi board to flexable. My goto is the Wedi panels. Almost as still as drywall and faster to install
I agree with you on the flexibility. Wedi is best in class in that department.
Jay Kerr says
I am remodeling a beach house, using Wedi board in the master shower. In the second bath I am installing a free-standing tub, and plan to tile the walls surrounding the tub. The tub will have a hand-held shower, but no overhead shower, and will sit 3” off the wall. Is there any concern with tiling over the existing sheetrock walls in this instance?
No. You can go right over the sheetrock as that wouldn’t be considered a wet area.
John Peterlin says
Marylandmarble.com just made me a custom shower pan. It came out very nice but was not inexpensive.
Tile guy (Dear Abby),
My contractor installed WEDI 3×5, 1/2 in on 3 sides of tub walls up to waste high. Then he left the rest green board? He said the water won’t get up there especially since it will be covered by 12×24 ceramic tiles.
I previously had 4×4 ceramic tiles with durock for 20 years. Only the tub corners were damp when it was removed during demolition but the Durock was surrounded the entire wall of the tub and under the tiles.
What’s another 3 pieces of WEDI? I’m so confused why he decided to do this accept to save himself on labor. Far easier to cut a large piece of green board then to get the WEDI board in nice and tight? He even had leftover WEDI board and sealant.
I’m tempted to have him rip out the green board. Frustrated. I’m providing the materials and there was no consultation on the decision to install green board in my tub wall.
I just purchased the wedi 36×36 shower kit. It comes with 4- 3×5 wedi boards. Trying to figure out the best layout on the walls since two of the walls should come out at least 38″ to account for the curb. Is 4 sheets enough?
You’ll probably need to purchase 1-2 more sheets. I would probably get 2 more as you can then run every wall to an 8ft ceiling and have 2ft left over (x3) which could be cut into strips and added onto the front of the shower to extend it out far enough.
Thanks for the article. For a diyer which modified thinset do u recommend for wedi boards? Keep in mind a thinset that stays workable longer is a plus for someone slower like me. Thanks!
It depends on the tile and what brands/products that you have access to. This post might be helpful.
Thanks. I did review this, but didnt see where Wedi wall panels fitted in with your diagram – I assume its under Backerboard? My wall tiles are ceramic 10″ by 16″ and thinking the Mapei Ultraflex LFT would be a good choice. Thoughts?
Also, outside of cost do you have any suggestions between using wedi .25″ panels on the floor verse using wedi subliner dry over ply substrate? I am using the Wedi ligno shower base so both of these approaches will need to be flush.
Yes, Ultraflex LFT would be a good choice for 10×16 tiles over Wedi board.
For the Wedi Ligno shower, I think it’s going to be tough to get the Ligno pan flush with the plywood substrate. That’s why the 1/4 inch panels would be nice. Additionally, I don’t think Subliner Dry is supposed to be installed directly onto the subfloor.
Code requires the area outside of a curbless shower to be waterproofed a minimum of 12 inches. So, you could order the Wedi panels to go around the shower only- then switch to regular cement board if you wanted to. It would save a bit of money but may, or may not, be worth it.
Also, you might check the Wedi warranty before deciding. They may have different tiers of warranty coverage and different requirements for each.
For my tub and shower remodel, I am using JM Goboard and DAP 3.0 sealant. Do you know if it would be practical as an extra measure, to cover the sealed joints with a membrane such as Redguard, just to make doubly sure of a water tight job? And thank you for your website, the information you post is invaluable !
I don’t think that’s a good idea. Either use the sealant and trust it or use thinset/mesh tape, and Redgard. Don’t do both.
Patti Yohe says
Hi, I have spent hours reading your posts and the comments. I have learned a lot, but I was wondering if you would do an update on the various foam boards for shower/tub walls. This post started in 2015, and I read that Durock foam boards are no longer called Durock. I wanted to see what your current recommendations are now.
I have a two wall tub (plumbing end and back wall) with a 6″ deep pony wall on the back end. The pony wall is 39″ wide x 36″ tall. The top will have a quartzite top on it, which is harder than granite. A vertical glass wall will be attached to the pony wall and back wall. I think I should use the foam boards for the two full walls and for the short pony wall. Since I have the pony wall with vertical glass on top, I made sure blocking is in place for attaching the glass wall, but I don’t know where to stop the foam boards. The entire bathroom has been gutted with all drywall gone. Should I end the foam board at the inside corner of the pony wall, or behind the pony wall/glass or continue past the pony wall/glass? We will be tiling with large format tile, probably 12″x24″. Where should I stop the tile on the back wall? Will the tile go behind the 6″ pony wall?
Also, the wall with the shower head is 39″ wide. (The wall behind the shower head is a hall closet. The bathroom is a rectangle less that closet space.) I have blocking in place for a glass shower screen/door. The tub is 32″ wide x 60″ long. Should I put the foam boards all the way to the outside corner (39″ wide)? Where should I stop the tile? 32″? 36″? 39″?
Thanks for any advice.
You want the waterproof backer board to be inside the glass so the backer will need to extend beyond the inside corner and, likely, to at least the middle of the pony wall. Also, you want the glass to be installed over the tile. So, the tile will also need to extend beyond the glass. A lot of times, people will stop the tile at the outside edge of the pony wall.
For the 39 inch wall, you can stop the tile short of 39-inches if you like. It should extend beyond the tub but if you want to stop at 35-inches, or whatever works, then that is perfectly fine. However, if you want to extend the tile all the way out to the end of the wall then you would usually have an outside drywall corner on first then tile up to that.
Be sure to check how plumb that end wall is if you end up tiling all of the way out to it. One more thing, both side walls on the tub usually will extend out the same distance. Not always, but usually.
And, yes, I need to update that post. I’m working on updating my trowel post right now and will be doing more updating this year. Thank you for the feedback.
What about schluter waterproof membrane over Durock cement board
I looking at buy a custom made solid shower pan with roll over threshold. I found a poured culture marble pan , or and acrylic pan. I am placing this new shower on existing floor and I will not need to remove only the hardwood floor under shower. Most grouted mud pan tile floor have issues so I was also trying to accommodate ada access for later use, this is a great article on different products and application So what do you think about me using the solid shower Pans
If it suits your needs and you’re happy with it then I think it’s a great choice.
I am doing a small shower in the basement. 48×32. Corner shower so only two walls. I am putting up Swanstone panels. I was planning on using GoBoard. Would the GoBoard be acceptable with these panels? Thanks.
I’ve never installed Swanstone and am not familiar with that product so I’m not sure if GoBoard meets their criteria or not.
TileRedi Shower Pan anyone? Neat blog. First shower for me.
a) If you have covered the TileRedi shower pans with epoxy adhesive for the tile and answered my questions maybe you could direct me to the date if you know it. I have one set in mortar as instructed already but, I can hear small voids when I tap on the pan. I’m tempted to pop some holes and fill the voids with epoxy. RediTile “techs” said no.
b) maybe 1/2” quarry tile (which I like) would provide enough to support to span worry of the voids.
c) TileRedi sells thin aluminum “flashing” to go over the 1/2” thick curb and up the wall a bit. I wasn’t crazy about that transition of material and originally planned to run the backer board over the curb and into the pan. For a smooth transition I placed 1/2” green rock sitting on top of the curb behind the backer board. That way my cove base tile could be on the same material and same plane as the rest of the wall tile.
d) then I read that backer board should not be in the pan (or, if so, held an inch above)
e) so, now I am back to the flashing and progressing as TileRedi recommends.
f) however, I see a tile guy using flexible, self-adhesive, window flashing to seal tub flanges to the walls. I really like that idea instead of aluminum. I would worry that aluminum would react to the minerals in backer board. I think RediTile used to sell stainless flashing. Still, I like the “fabric” flashing as it would seal fasteners better.
Thank you for all the information from 2015 forward he any help here. Rbs
I’m not sure what questions are being asked but I’m have not tiled over a Tile Redi pan and am not sure how much help I can be. It sounds like you’ve been in touch with their tech department and I think it’s prudent to follow their instruction.
I have put up the Durock in my walk-in shower, only to discover the writing on the wall. LOL. I think it says to use the smooth side on walls. But I have the rough side out. Is that a problem? Seems to me that with a couple coats of Red Guard, I should be just fine.
Also, I’m planning to put a quartzite counter top on the shower bench, to match the vanity. Is there any problem with that?
Thanks for this great diy site.
Durock works either way and a quartz bench is common. Carry on!
Thanks. I will not get the bench slab before I finish tiling the walls, most probably. Which means the tiles won’t come down on top. If I use backer rod and silicone caulk between the slab and wall, is that ok? Or do I really need to get and mount the slab first? Sized to extend under the tiles. If I do that, I have to cut the slight angle (slope) on the bottom of the side tiles, right?
It can go on after like you’ve described
Searching for an answer to the question ‘ben’ asked, I found this wonderful blog. Thank you for maintaining it.
I’ve read what I can find and see folks reporting problems with deflection of the wall mounted bowls on in-wall systems, most of those coming from improper installation of the carrier inside the wall. The issue comes mostly from failure to install the carrier perfectly flush with the stud wall and surround of the carrier, thus creating a space that will allow tile backer such as drywall and foam board backers to flex under pressure below the bowl bolt attachment.
I’m using Hydro Ban board in my current project, love working with it, and hope it performs as expected. I have cut a piece for tile behind the wall hung Toto bowl covering the Geberit carrier that I have installed, but started to wonder whether it is rigid enough to support the weight of the bowl and any human who may mount it down the line. I’m not concerned about the top of the bowl, but wondering mostly about the sides and bottom of the Toto bowl.
I’ve got the carrier perfectly flush with my stud wall, so I’m not so worried about the kind of deflection folks on the net report. What I am worried about is possibility of the foam compressing behind the tile below the support bolts of the carrier.
My gut tells me to substitute Hardie board or maybe even 1/2″ plywood in this area to avoid potential deflection problems. But, with that said, the Geberit carrier actually has square tubed supports that have vertical tubes directly behind the where the edges of the Toto bowl will mount and hit the tile and backer when finish installed.
Any thoughts on this? Any thoughts about using 1/2″ plywood in this section of my tile backing as opposed to Hydro Ban Board or even Hardie?
Thanks so much!
It sounds like you’re using Hydroban Board which has a foam core. As far as the foam compressing, part of the equation is what tile you would be installing over the top of it. If it’s a large porcelain tile then the compression shouldn’t be a factor. If it’s small mosaics then it might.
But I think you are also talking about how much support is around the sides of the carrier? Because that could cause flexing no matter which backer board was chosen. Some substrates, like Hydroban board, would flex more than, say, Hardibacker. In this case, I don’t have a lot of insight other than follow the installation instructions and maybe call the manufacturers and see if they have any testing done in this regard.
Wall-mount toilets aren’t the norm for me so I don’t have a lot of insights that I could share.
Thanks to Covid supply chain issues, it’s almost impossible to acquire stuff that was already difficult (Dec 2021). I’m trying to find a source for *any* foam waterproof backer board. I found one supplier that will sell goboard at twice the retail rate (in packs of 7), so to minimize the number of boards needed for my tub enclosure, I have the following questions:
1. I want to tile all the way up to the ceiling. Is it necessary to use goboard above the height of the showerhead or can something else be used up there?
2. For the rest of the bathroom – wainscot and walls behind vanity and toilet, etc. – is it OK to just tile on the drywall? Is there any kind of treatment needed, or special kind of drywall? Or do you recommend cement board?
OK, I just finished reading all the comments on this blog post and answered both my questions. At this point I’d like to leave a comment about your website, which I’ve been reading for years, and seems to have undergone a format since last I visited.
Thankfully you’re pretty prompt about answering people’s questions so most of the time it’s easy to tell who you’re replying to, and what questions you’re answering. But not always! Might be more work, but if you could maybe put the person’s name to whom you’re replying, some answers would be more clear.
I’ve learned a lot from you over the years and I really appreciate the effort you take in answering so many questions. My other favorite online tile guy was Floor Elf, who seems to be MIA these days.
Yes, supply chain issues have created problems with foam backer boards. Goboard and Wedi board should be in decent supply. Hydroban board and Kerdi board are tough to get a hold of right now.
The good news is that, yes, you can install drywall above the showerhead and drywall in all the non-wet areas in the bathroom for your wainscot tile.
Keep in mind, that you can’t tile over drywall compound. So you either have to paint primer over any drywall compound or use thinset and mesh tape, instead of joint compound, to tie in any seams that will be covered by tile.
Google is forcing some changes and not all of them are for the benefit of the user. For example, I’ve had to remove the “nested” comments that allowed you to better understand who was being replied to. I have plans to overhaul this website in about a year. Until then, I’m just going to try and work on coming out with new content and keeping the current content up to date.
Thank you for your feedback. It is helpful and appreciated.
“Keep in mind, that you can’t tile over drywall compound. So you either have to paint primer over any drywall compound or use thinset and mesh tape, instead of joint compound, to tie in any seams that will be covered by tile.”
I assume you mean drywall/paint primer, like Kilz? I’m tiling some of my bathroom walls and my drywall guy put compound over the screw heads. I stopped him before he got to the seams.
Correct. Paint primer like Killz, Zinsser, or that type.
I’m installing Permabase WP (waterproof) board in my shower. The installation instructions do not say how deep to drive the screws. For Permabase cement board the video shows driving the screws flush with the board.
Would it be ok to drive the screws just below the surface of the board (like with GoBoard) and apply sealant over them since it’s not as solid as the cement board?
The data sheet for PermaBASE WP says this: “Install screws flush with surface, do not overdrive screws.”
It appears to be similar to their cement board and their cement board has always been the best one to use and install, in my opinion.
Instead of applying thinset between seams of the permabase waterproof board, do you think would be ok to use Sika 10-fl oz Construction Adhesive Lowes Item #78066,Model #106403 instead
No. I would definitely go for thinset and mesh tape.
Can the thinset/mesh tape be applied between/over the seams at the same time when the tiling contractor starts tiling the walls, or does it have to be done beforehand and be dry before starting tiling?
You can do it as you install the tile. I prefer to do it prior to this step so that if a tile is removed during installation then it doesn’t pull the tape off with it.
But I’ve seen installers do it both ways.
I installed the Permabase WP backer vertically on the two walls but I overlooked staggering the vertical joints as the mfg instructions recommend.
I haven’t applied thinset or mesh tape to the joints yet, but it would be a lot of work to remove the boards and stagger them. What problems, if any, would it be to leave as is?
I think if you can stagger them that is the best way. Otherwise, you take the chance of allowing for too much flexibility which could cause stress on the joint and crack the tile right at that joint in the cement board.
I’ve seen tile crack at the seam and run the whole length of the wall before but that was a case of not staggering along with no mesh tape.
mike mills says
I’ll be installing the 24″ wide porcelain tile around the edge of the tub with only one row. The tub does not have a shower head on the wall, only a handheld shower head that pulls out from the corner of the tub.
I have one sheet of regular drywall…can it be installed above the tile in the tub or should I use green board?
The backer behind the tile will be Permabase waterproof board
Drywall is just fine if there’s no shower head above the tub
After installing Permabase WP on the 2 wall separate shower, I left a 1/8″ gap between the seams of the boards (horizontally) and in the corners (vertically) and between the bottom of the boards and the flange of the pre-fab marble pan. I then applied:
1) Thinset and mesh tape between the seams and corners.
2) I cut 3″ wide strips off a roll of Kerdi and applied over the thinset/mesh tape and applied using GoBoard sealant. I did this because thinset is not waterproof.
I applied GoBoard sealant between the bottom edge of the boards and the flange of the shower pan. Should I leave the sealant between the gap of the bottom edge of board and shower pan or:
1) Remove the sealant thereby the 1/8″ gap remaining?
2) Leave the sealant and apply strips of Kerdi membrane using GoBoard sealant?
I see no downside to leaving the sealant in the gap and going right over it with the Kerdi membrane. It’s likely that it would get filled in anyways when you apply the sealant for the Kerdi strips. So, #2 is how I would handle it from here.
The front of my prefab pan for my separate shower has a 8′ wall on the left side and a 18″ tall knee wall on the right. After tile installed and thickness of thinset the approx. width for a door will be 45.5″. I’ve read that the min. width of a shower door should be 22″, but a 45.5″ opening for a door will result in less than that due to bumpers required for the door. A wider door can be obtained using a hinged type but I prefer the looks of a slider.
The shower glass guy came to my house today and I told him I could cut a notch in the knee wall and a notch in the bottom lip of the pan so a wider door could be installed, and then I would install the tile up to the edge of the glass and put silicone. After the glass installed the granite knee wall cap would be notched to fit around the glass. He said that if I did that it would eventually leak and that the tile should be installed behind the glass. My thinking was that if silicone on the inside edges of a fish tank will prevent leaking then installing tile up to the edge of the glass to the knee wall should prevent leaking as well. Do you think there would eventually be problems with leaks if tile installed to edge of glass and apply silicone where the tile meets the glass?
One of the things that you could do is install a U-channel in the tile before the glass is installed. I’ve done this on occasion when there was a reason to. The glass is installed in a U-channel a lot of times. Your glass installers may be using it on the stationary panel already. Then you could install it on the other side. However, if your tile is already installed it would be a very tough thing to do.
Additionally, you mention notching the bottom lip of a prefab pan. This doesn’t sound right to me. Is your shower pan fiberglass? If so, are you talking about notching the waterproof flange? I don’t think you want to do that but maybe I’m misunderstanding the situation.
A hinged enclosure would allow for a 28-inch door. That’s a big difference from a 22. The hinged doors are less expensive and it sounds like would be the easiest to install without notching existing tile. I would take another look at this. The nice, wider opening is a big advantage over a narrow door.
The pan is made of marble.
Yes, I’m talking about notching the lip of the flange which is around the perimeter of the pan where the backer board sits on top of it. I cut a piece of granite using my sawzall and worked great, so should be no problem cutting the flange.
I don’t think it’s a good idea to cut the flange. That’s probably what the glass person was referring to when he mentioned the bit about leaking.