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marco72 11-07-2012 11:58 AM

A shower wall without cement board is possible?
Good morning,
I'm remodeling my shower's walls. My contractor applied 1 layer of a product called Aquabar B ( a paper sheet that works as a a moisture retarder ) on the stud wall, then he covered the paper with 2 coats of concrete and then tiles. No wonderboards or other stuff. Starting from the stud, just Aquabar B, concret and tiles. My question is: Is it enough to avoid possible water damage? I checked everywhere and it looks like everybody use cement boards on the stud walls before starting with concrete and tiles.
Any help?
Thank you :)

firehawkmph 11-07-2012 08:04 PM

Here's a link for the installation guide for aquabar b:

Mike Hawkins:)

marco72 11-07-2012 08:37 PM

Thank you for the link, but I alreday saw that pdf. That's why I'm so confused and I don't know what to do. On the other side my contractor, said that it'll work good also without cement board, and of course I don't trust him. That's why I'm here :(

chrisBC 11-07-2012 10:26 PM

Looks like it can be done with either cement board or a mortar bed. Mortar beds were done in the past and worked well.

marco72 11-07-2012 10:42 PM

Thank you for your help. I contacted the company that create this Aquabar B and they told me that they only recommend their product behind a cement board and mortar bed. Should I trust the company or my contractor?

chrisBC 11-07-2012 10:45 PM

Says in their instructions a mortar bed is fine. I can't see any reason not to trust what he is doing.

marco72 11-07-2012 10:49 PM

So, even if I saw thousand videos where people use cement boards applied on stud walls, even if the company wrote me to use their product only behind cement board and then mortar bed, even if on their instruction they say that Aquabar B is not recommend me to follow my contractor idea? So sorry if I'm asking you all this stuff, but I'm so scared that my shower wall will fall apart in 1 year...

chrisBC 11-07-2012 10:57 PM

As I said, it says right in their instructions that it can be installed behind EITHER cement board or a mortar bed. I am not an expert on this particular product, just going off what their literature says. I do know that there is nothing wrong with a properly done mortar bed. It also shows right in the installation instructions that it is a proper installation with a cement board/mortar bed, implying to me use in a shower area. It does say that with CBU, a waterproof membrane should be used, as is standard practice. With the mortar bed it may have different waterproofing requirements or not need one, I don't know as I don't do bathrooms with mortar beds.

As long as the mortar bed is a strong and stable substrate for the tile, I would image it being much superior to something like greenboard, for standing up to water and moisture.

Also I don't understand why anyone would put a mortar bed over cement board, seems like a bit of a silly idea and redundant to me.

If you don't trust your contractor why did you hire him? Is there no warrany on the bathroom? is the work done yet? if not tell him you would prefer the cement board if this really does bother you, or ask about the possibility of a warranty on the work.

marco72 11-07-2012 11:03 PM

Thank you very much for your help Chris.
I'll discuss with him tomorrow morning about that. The job is not totally complete yet, and I hired him only becasue someone recommended him to me, but so far, this people work without telling me or my wife what they're doing. I think the best way should be talk about the job and answer questions that, as I'm paying them, I deserve to have.
Anyway, I really appreciate your help :yes:

chrisBC 11-07-2012 11:07 PM

No worries... BTW i'm not recommending you to "follow his idea" as much to trust the person you hired, assuming the rest of the work is up to a good standard.

marco72 11-07-2012 11:16 PM

The rest of the work looks fine, even if they didn't hot mop the shower pan, but they just add some black waterproof layer that I don't know ( but I trusted them ) and when I asked for a water test they told me that it wasn't necessary. After that and the fact that 1 day they didn't show up at work ( but I know that with someone sometimes it happen ) when we started to talk about this Aquabar and the cement board I was a little bit confused

firehawkmph 11-08-2012 09:14 PM

can you post some pics of what they have done so far?
Mike Hawkins:)

marco72 11-08-2012 09:23 PM

4 Attachment(s)
Here the pics. You can see there's only a layer of Aquabar B, then metal leth and then something that could be concrete or mortar bed ( I didn't ask which one they used ).

marco72 11-08-2012 09:25 PM

They added CBU around the bathtub, but not in the shower...:huh:

firehawkmph 11-08-2012 09:36 PM

Not saying it won't work, but it sure seems strange that they would use the cement board around the tub, but not in the shower. Are your walls lathe and plaster? It looks kind of sloppy around the shower area. Looks like lathe showing up high on the wall next to the mud wall. Not really sure why they did what they did, but not the way I would do it.
Mike Hawkins:)

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