Curbless Showers have exploded in popularity. But did you know that there is only one industry-accepted method for constructing a shower with no curb?
This post will explain how to build a curbless shower using the only industry-accepted method for doing so.
Estimated reading time: 4 minutes
What is a Curbless Shower?
A curbless shower has no physical barrier to step over to get into the shower. Hence, they are sometimes called barrier-free, zero-entry, or simply no-curb showers.
How to Build a Curbless Shower
There is only one industry-accepted method for constructing a barrier-free shower base. The detail can be found in the Tile Council of North America’s Handbook for Ceramic, Glass, and Stone Installation (TCNA) methods B421C and B422C. [1]
Technically, they break it into two details but it’s the same method with two different drain details. More on this later.
Sealed System Showers only
According to the TCNA, if you want to build a shower with no curb you have to use a sealed shower system.
The Schluter Kerdi Shower System is an example of a sealed shower system. It uses a bonded waterproofing membrane (A118.10) on the walls and shower pan.
Curbless Transition to the Floor
The reason the sealed shower system is required is that it’s the only system that will properly waterproof the transition from the wet shower area to the dry floor.
High point of shower
You have to waterproof up to the high point of the shower and beyond.
If a shower has a curb then that acts as a natural barrier to contain water inside the wet area. However, when the shower has no curb then it’s important to make sure of two things:
- The high point of the shower is outside the wet area
- Waterproofing extends well past the high point.
Industry standards call for waterproofing a minimum of 12-inches past the high point of the shower. Further, I think it’s a good idea to add a capillary break to your curbless shower even though it isn’t an industry standard.
Two Different Drain Options for Curbless Showers
As I mentioned, there is one way to build a shower and it has two different drain options. These are:
Bonding Flange Drain
Examples of bonding flange drains are the Kerdi drain and FloFX. They use a topical waterproofing system and stop the water immediately below the tile layer. Another example is the Noble Freestyle Linear Drain.
Divot Drain Method
There’s also the divot method. This is a way of adapting a sealed shower system to a traditional water-in/water-out clamping ring drain.
Prefabricated Shower bases for curbless showers
You might be wondering if you can use prefabricated shower bases that let you build a curbless shower without cutting into floor joists.
Those types of shower bases are OK because they are using their own variation on this exact method. Make sure to follow the manufacturer’s installation instructions when using a pre-formed curbless shower kit.
I’ll have more to say about pre-formed shower kits in the future.
The Final Word on How to Build a Curbless Shower
The only proper way to build a curbless shower is with a sealed system like the Kerdi Shower System. From there, you can use either a bonding flange drain or create a divot to adapt the bonded waterproofing membrane to a 3-piece clamping ring drain.
There is no industry-recognized method to build a shower the traditional way using water-in/water-out shower construction.
Foam shower receptors for curbless showers are OK as they rely on a sealed shower system to be properly installed.
FAQ about curbless showers
No. The Americans with Disabilities Act has several shower design requirements that must be met and creating a barrier-free entrance fulfills only one of the stipulations. [2]
Linear drains can work great with barrier-free, curbless showers. But just like the smaller center drains, linear drains come in two types. You want to make sure you get a drain that works with a sealed shower system.
A linear drain that’s compatible with a 3-piece clamping ring drain isn’t going to cut it for a curbless shower.
A properly built curbless shower will have the high point outside the wet area. This will keep water inside the designated shower area. However, there are design elements that can help with water management in curbless showers.
Further, adding a capillary break can help with water management.
In my opinion, there is a way of waterproofing the shower pan that is more successful than another. However, with proper design and construction, curbless showers will contain water inside the designated shower wet area.
References
- Tile Council of North America
- ADA
uWish you had. ideo or photos for steps. I’m building my 1st curb less shower walkin shower floor!
If you’re building a curbless shower system, I would recommend using Schluter or Wedi Ligno shower system. Wedi has a subfloor lowering kit and Rapid Recess can be used for Schluter system. Schluter has great videos and instructions.
Thanks for the feedback. I’m always trying to put better information out and a step-by-step curbless shower would be very useful to people, I think.
James,
I am installing a curbless shower using Schluter. Ideally the tile in the shower (I’m using a thinner tie in the shower) should be flush with the floor tile at the shower door. Also, the waterproofing layer below should be at the same level as well. Can you explain how to calculate the different levels of the curbless shower vs. the floor outside? I am using a 5/8 tile on the bathroom floor and a 1/4 tile in the shower.
So, your tile outside the shower is 5/8 inch thick? That’s more than normal. What is the width x length of them?
Assuming the tile is 5/8 and they will sit on top of Ditra you’ll be at 3/4 + some mortar. I would figure another 1/8 depending on the size of the tile. So, outside the shower area you’ll be 7/8 inch (+/-).
If we figure the shower pan is 3/4 +1/4 tile +1/8 of mortar under the shower pan you’ll be at 1 1/8 inch for the shower pan. However, that’s recessed. If the recess is 3/4 then you are 3/8 above the subfloor.
So you would need to build up the recess of the shower pan by at least 1/4 inch to be flush with the floor tile.
This means the waterproof area of the shower floor will be higher than outside the shower. You will have to be careful that the shower enclosure is inside the raised shower pan area. It wouldn’t be a bad idea to reselect your tiles and make it so the water proof area is more even.
So – shocked at what folks want to charge me in Boulder, Colorado, I’ve removed a fiberglass shower pan, demoed the walls (original 1993 normal wallboard with only thinset and subway tiles on top, no waterproofing and tore out the plastic door enclosures for a 33″ x 72″ shower).
I’ve installed Durock, taped and thinseted the seams, used paintable water membrane (two coats) on the Durock and also on the 15/16th OSB subfloor with 24inch on center joists.
I plan to use a poured pan and curb (masonry mortar) and then seal that with Hydroban before I tile on top of that. My question: Do I need to use an additional uncoupling membrane and/or metal lath before I put on my ‘dry-pack’ masonry mix for the pan and curb? Thanks!
It sounds like you are building what is known as a ‘sealed shower system‘. Check out the post that I’ve linked to. You will want diamond metal lath if you are building this shower over a wood framed subfloor. For a curb, you can either wrap cement board and hydroban over a wood curb or simply use the foam curb that comes with the Hydroban system.
FWIW, I would encourage you to use the Hydroban sheet membrane for the shower pan rather than Hydroban liquid waterproofing. The liquid is too prone to user error and the shower pan is a critical point to get right.