What should be put on shower walls before tile?

giuseppe_paoloApril 6, 2011

We had the old tile knocked out and new plumbing done.

Normal non waterproof (im assuming) fiberglass insulation was put back and then durock (also seemingly non waterproof) dry wall was out up.

Shouldnt thry hsve used waterproof drywall? Is the old insulation ok?

What are all these ither materials I here about for shower walls? Kerdi etc.?

Jve seen talk sbout Vapor barriers and waterproofing and Im afraid mine wasnt done right and need to fimd out now before tile goes on.

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Unless you are going to cover the walls with a membrane like Kerdi there should be NO drywall of any kind in your shower.
Are you saying that they put drywall up over the Durock? That really makes no sense.
It's also acceptable to put a vapor barrier behind the Durock.
Is this a tub/shower or just a shower? If a shower only, what kind of pan are your using?

    Bookmark   April 6, 2011 at 12:32PM
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giuseppe_paolo I'm astonished that your internet searching skills are not as good as your internet posting skills.

at this point, tell the installers to put a liquid paint-on or trowel-on membrane onto the Durock, and on the floor. Before posting again, search and read about Hydroban, and Redgard. There are many more like those two. Go to the corporate web sites and also to tile-setter forums. And forget the helpful advice about the "barrier" behind the Durock. Also forget about Kerdi since your installers don't know what it is, and to do Kerdi is a whole system including the special drain.

The drain is another big subject. terriks asked you about the pan, which includes the drain.


    Bookmark   April 6, 2011 at 12:44PM
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And forget the helpful advice about the "barrier" behind the Durock.

Are you saying that putting a vapor barrier behind Durock is not longer an acceptable way to build a shower? I would agree that waterproofing over the backerboard is a better method, but I believe that it is acceptable to put the vapor barrier behind.

    Bookmark   April 6, 2011 at 2:14PM
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I mentioned the vapor barrier behind the Durock because others who might read this thread might freak out if they don't have waterproofing over their backerboard, when in fact they have a vapor barrier behind. And you definitely don't want a waterproofing behind and on top of the backerboard, leading to a potential for a "moisture sandwich". More isn't always better!

    Bookmark   April 6, 2011 at 2:24PM
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ok, ok, ok, got it. i think it's best to focus on the one question, or need, of the current thread, and not to explain for the general reader or the general case.

    Bookmark   April 6, 2011 at 7:31PM
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thanks guys and yes I did research about it but was unclear. yes it is just Durock up which is supposedly fine. Met with tile installer today and he said it doesnt' even really need it but, he will use Hyrdroban.

shower floor is concrete and already pitched but they will be putting the waterproof membrane down and 6-8 inches up the shower walls.

You mention to research butt hat was actuqally the problem, all my reading about the different options and bad jobs had me worrying a bit but seems that we have done so far is good and that it will be getting the Hyrdroban over top so should be all set.

thanks for the input though and maybe this can help others, not only DIY, but sometimes ppl get sidejobbers doing the work and want to make sure its done right. Heck even some so called pros might take shortcuts whether they know better or not so always good to educate yourself as much as possible so you know what to look for, ask for, or confirm was use to make sure things are done right.

    Bookmark   April 7, 2011 at 3:03AM
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There are many construction guys who put the membrane on the sloped floor and then only 6-8 inches up the shower walls.

Ask for more. Order more.

What in the world makes him want to stop at 8 inches above the floor? Once you've gone to the store and bought the stuff, opened the can and started the job, why not go up the wall to cover the wall too? Why stop at ankle height? What kind of minimal good-enough attitude is this? Tell him not to argue back and not to lie about this. Tell him you need to see photos if he tiles before showing you he covered the wall. I've seen lots of guys resist when told to cover more wall than they think is going to be enough. I don't get it. What do they gain by insisting that they know how much is good enough? One installer I know told me he would paint the corners (wall junctions) up to the ceiling, but not the flat wall. I don't get it. I was the order-giver and he contradicted me. We broke up later.


    Bookmark   April 7, 2011 at 7:56AM
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Met with tile installer today and he said it doesnt' even really need it but, he will use Hyrdroban.

Did he tell you why your shower doesn't need any waterproofing? Many think that the tile and grout provide the waterproofing, but they don't. Water can and does get behind the tile, AND can pass right through the Durock. Water won't damage the tile, grout or Durock, but it can cause damage to the structure behind the Ducrock, and that's what you need to protect against.

    Bookmark   April 7, 2011 at 11:58AM
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this is a good point. You have a long uphill struggle ahead of you when your guy says "it doesn't need it". Fire this guy. He won't improve.

    Bookmark   April 7, 2011 at 12:22PM
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I believe the "membrane" the OP is talking about going 6 - 8" up the wall is probably the shower pan liner. As long as there is a vapor barrier behind the durock, this may still be a perfectly acceptable shower install. If this is the case, telling the OP that a topical membrane on top of the durock is necessary is just plane bad advice.

It might be good to ask more questions and make sure we actually understand the install before telling the OP the shower install is not acceptable. It is possible we are dealing with nothing more than a case of ignorance on the part of the OP and incorrect terminology causing confusion.


1. Was a layer of plastic(vapor barrier) installed behind the durock? Don't guess - ASK.
2. Is the membrane the tile guy spoke of a thick, typically gray, piece of rubbery plastic? If so, this is a shower pan liner and durock should be installed afterward and overlap it.
3. What sort of warranty does the tile installer offer?

    Bookmark   April 7, 2011 at 12:22PM
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davidro1 - He may be saying it doesn't need it because there is already a vapor barrier in place behind the durock. How about making certain before making rash judgments based on incomplete information? I understand how it appears to us, but we are operating from a distance, our only eyes being those of the OP who may or may not know what s/he is seeing. You may be correct - I don't think we know enough yet.

Pictures might help.

    Bookmark   April 7, 2011 at 12:34PM
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Exactly Alice. That's why I mentioned it being acceptable to have a vapor barrier behind the Durock in my first post. But if there is no barrier behind the OP does need some sort of waterproofing on top of the Durock. The installer should be telling the OP why he doesn't think that Hydroban is necessary. It might be helpful to the OP to check out the John Bridge Tile Forum, especially the thread on shower construction.

    Bookmark   April 7, 2011 at 12:46PM
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giuseppe_paolo - the two main ways to do a shower wall are:

1) A vapor barrier tacked to the studs with cement board over that. Water and vapor can go through the grout and cement board, but should be stopped by the vapor barrier. It is probably the fastest,cheapest, and most common way to go.

2) Cement board screwed to the studs and then covered with a membrane. These can either be a sheet type membrane like Kerdi or a painted on membrane. Either way, water and vapor that go through the grout are stopped by the membrane. The process is more expensive, but the membrane is more substantial. It also allows a continuous membrane from the pan all the way up the wall.

Either way is acceptable, but #2 seems to be considered "top of the line" .

The thing you don't want to do is to do a membrane, then cement board, then another membrane. If anything fails, that creates a moisture sandwich between 2 membranes.

    Bookmark   April 7, 2011 at 1:05PM
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yes its going to be #2 with durock and then hydroban on top of that. what i was talking about previously was hte shower pan membrane liner going 6-8 inches up the sides.

    Bookmark   April 12, 2011 at 12:47AM
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can anyone help me. ripped out the shower due to bad water damaged. reframed and perma cement board over 4mil poly. then did redgard. now reading that this is bad. what should i do

    Bookmark   December 2, 2012 at 1:27PM
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You might want to start a new thread with your question and link this thread, if no one replies to you here.

    Bookmark   December 3, 2012 at 10:02PM
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