Bathroom shower and floor prep

randekaspApril 25, 2013

(posted under remodeling as well)
I had to let go of the person who was remodeling small master bathroom, when it appeared that he was cutting corners without letting me know. He has already put concrete on the walls of the shower. A new contractor said that only one layer of moisture paper had been put in shower wall under concrete and that there was no hardibacker . The new contractor told me that he always uses two layers of moisture barrier. Also, no moisture barrier had been put under the hardibacker on the floors and that needs two layers as well. Could I please get your opinions on this? Thank you!

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First, I'm a little confused by your post. So I'll write a little, then you can come back to clarify.

Shower walls: If they are "concrete", is sounds like he floated the walls with mud. That can be a top-notch installation that can give you perfectly flat wall surfaces to tile on and dead-on 90-degree corners at the wall-to-wall intersections.

Usually a barrier of some sort will be put behind the mud...typically tar paper...then wire lathe over that. The mud then gets keyed to the lathe and troweled/screeded flat.

All you really need is one moisture barrier or membrane behind the mud. And with floated mud wall, you don't need or even want hardibacker or any other type of tile backer board on the wall. You tile right on the surface of the mud.

With your new guy saying he always uses two layers, realize that more than one is not always better, and depending on what membrane is used, it can even be prohibited by code. Code, as well as best building practices, requires that there be only one vapor barrier within a wall. While there is a lot that goes into the reasoning, the goal is to not trap moisture between two barriers.

So for the shower walls...if your first guy used one "barrier", then wire lathe, then put a thickness of mud or "concrete" on the walls, that's actually an excellent installation.

Regarding the "hardibacker on the floors". If this is on a shower floor, Hardibacker, or any other type of tile backer board, should not be used on a shower floor. On a bathroom floor it's fine, But on a shower floor? It's the wrong product.

If it is indeed a bathroom floor and you want waterproofing on your bathroom floor, that waterproofing should go on top of the hardibacker, not underneath it. The reason being that on any floor, if a tile backer board like Hardi is used, it gets set in a bed of thinset on the subfloor, then screwed or nailed to the subfloor. The fasteners will penetrate any waterproofing membrane.

If you can clarify what methods and materials were actually used it would help. Example, does it sound like your old contractor did "floated mud walls" as I described above? Is that what the "concrete" is? And your new contractor uses two moisture barriers? What material are they made from. And why does he recommend two versus one? And the "floor" it the bathroom floor or the shower floor we're talking about?

Details help. Best of luck!

    Bookmark   April 26, 2013 at 11:17AM
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