Shower waterproofing and vapor barriers: Part 5

tile shower waterproofing wrap-up
Wrapping up shower waterproofing. (Image from Google Images)

Part 5: Conclusion

The final post of this series will review the three different methods for waterproofing a residential bathroom shower that have been previously discussed and the whys, or why nots, for each method.

Conventional Shower Construction with Durock cement board and 6 mil plastic
Conventional shower construction using Durock cement board over a plastic vapor barrier. (Image courtesy of Tiger Mountain Tile Inc of Issaquah, WA

Traditional showers

The good:

lowest cost

tried and true

Not-so-good:

water is allowed to soak into substrate which may lead to mold growth and minerals coming to the surface (efflorescence) through the grout

Liquid surface waterproofing

Hydro Ban tile swimming pool construction
Surface waterproofing is applied over the surface and the tile adheres to it. (Image courtesy of Laticrete International)
The good:

blocks water at the surface, rather than letting it absorb

easy to install

Not-so-good:

lack of vapor protection

more prone to user error by not getting spots thick enough

Waterproof sheet membranes (and foam board)

Waterproof sheet membranes come in rolls and are applied over the surface for tile waterproof applications. (Image courtesy of Noble Company)
The good:

blocks water at the surface, rather than letting it absorb

excellent vapor protection

Not-so-good:

expensive

sheet overlaps can cause flatness issues

It’s important to remember that all three of these methods are specified by the Tile Council of North America. There’s no right or wrong, it’s up to you to choose the one that works the best for you.

If I had my choice, I would use a sheet membrane on every project. I think it’s the best way of waterproofing a shower. Unfortunately, not every budget allows for it.

Catch the parts of this series here:

Part 1: Waterproofing membranes vs Vapor barriers

Part 2: Conventional Tile Shower Construction and Water Management

Part 3:  Liquid Surface Waterproofing for Tile Shower

Part 4:  Surface waterproof sheet membranes for tile showers

7 comments

  1. Ok I’ve read your whole piece and now I just want some confirmation about how we are going to proceed. Our home is a Craftsman. All areas of the home have been done very well except the bathroom. Here they scrimped a bit choosing to use sailboats over lathe and a glued on shower surround. We intend to keep the tub but want to use subway tile in the bath area. From your article I have many choices..ultimately if I am going to invest my time and supplies I don’t want to worry about mold etc ruining or making more work for myself as I/we get older. We want to do it right the first/ last time. What would you do?

    • Hi Debra, if you’re keeping the tub and just doing a tile surround the risk of failure is lower than if it were a tile shower floor. Any of the systems will work if they are installed properly.

      Cement board with plastic or felt paper behind is the most economical. Cement board with a product like Redgard or Hydroban wouldn’t cost much more. And if you’re doing the work yourself some Kerdi fabric isn’t a big expense and is probably the best way.

      Sorry for the politician-type answer but all three systems work. Doing things properly and reading the instructions is more important than the products used.

  2. When using a liquid waterproofing membrane is it a waste of time to use durrarock?

    • The problem with liquid waterproofing over green board is the possibility of even a slight comprise. Even a hairline crack would result in total demise of the surround. Green board is still only drywall, exposure to water turns it to mushy goop.

    • It’s not a waste of time. I don’t think you’ll find a liquid that is ok for sheetrock. And you won’t find many sheet membranes that are ok with it either.

  3. My issue involves a recessed shower in Florida. The builders in this state are not required to use any form of liner whatsoever. I have a terrible smell that is located behind the shower wall, in the guest bathroom closet. I don’t have a shower liner. Yet, there is no moisture. What could this be from? No liner and the water seeping down past the floor tiles into the substrate and odor coming back up???

    • It’s hard to say. If you’re not using your shower then it could be sewer smell coming up from the drain. Otherwise, is hard to know. It could even be a mouse died in the wall or something.

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