Just poking in here – its been a while.
We are in the process of reno-ing our bathroom, and have pulled down the tile and drywall on an exterior wall. I went on a pricing journey to our local “big boxes” and got conflicting information on the Denshield tile-backer, so I thought I’d turn to you folks.
On the Denshield installation notes it says that no membrane is required behind it since the Denshield has its own integral waterproofing. According to one of the Box store employees, I should be removing all the plastic, and putting this stuff up on bare studs, according to the other, the product doesn’t live up to its claims of being a membrane, and I should be replacing all the plastic on the walls with new stuff since it’s been compromised by the existing screw holes etc.
If it were cement board, I’d probably just put a new layer of plastic over the old stuff and be done with it, but a double membrane can lead to as much trouble as none, so I don’t want to screw this up.
I know Denshield is a fairly new product, so field testing is likely limited, but I am hoping someone has an answer one way or the other.
Replies
I happen to like DenShield, but I know a lot of other contractors still prefer cement-based backer because the core is not waterproof. But the core should never get wet because the waterproof membrane is on the face. That is, the surface the tile goes on.
I can't see any point in a membrane behind the DenShield. If water makes it past the face of the DenShield, the additional membrane will only help to keep the DenShield wet which it is not designed to tolerate.
Denshield isn't all that new. I started using it about 10 years ago now I think.
I've done it both ways with no problems. I like this product a lot.
The one thing that always made me scratch my head was that, although the board itself is covered with a waterproof membrane, the joints are not -- they are just treated with glass mesh tape and thinset. I have recently started using the Kerdi-Band to tape the seams -- issue solved.
FWIW, as an experiment, I installed a shower about a year ago now where I used Kerdi on the pan (and 6" up the wall) with a Kerdi drain, and Denshield on the walls and ceiling, taping the seams with Kerdi-Band. So far, everything's been great. I did install a membrane behind that one, just because it was easier to skin the whole room rather than change things around for the shower.
Mike Hennessy
Pittsburgh, PA
So the material costs must drop
With only bringing the Kerdy up 6" ? I'm designing my shower right now and have been thinking
Kerdy but not to happy about the price.
Yep, the price goes down. But you also save some time by not having to do the walls, other than hang the board and tape, which you have to do anyway.
I laid the floor and ran a 6" strip of Denshield "curb" around the perimeter. Ran the Kerdi up over the "curb" and hung the denshield over that. Don't have a good "done" pic, but here's one of the floor and curb.
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Mike HennessyPittsburgh, PA
It's hard to tell from the picture, but I assume that the tile backer is not up yet?
Right -- not up yet, so I could run the Kerdi up behind it a bit and lap the seam with some KerdiBand.
Here's a pic with the backer up. The floor is covered with a piece of Masonite for protection in this pic. The seams are not yet taped.
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Mike HennessyPittsburgh, PA
So the Denseshield goes shingle laps over Kerdi
and buts into the curb ?
Seems obvious but want to make sure I've got it straight.
Sorry to butt in here folks, but doesn't a roll of Kerdi fabric come with the shower kits? along with the drain kit, base, curb, corners, and Kerdiband?
Unless of course you are just purchasing the drain kit, a roll of Kerdiband, and a roll of fabric for a dry pack base? If you are using the old dry pack base system then why would you use the Kerdi?
I have seen many showers which were 80 years old using the old system which were still in great shape.
I don't think the Kerdi system is all that expensive. We purchase the 48" kit for about $340 and the 60" kit for about $380. It takes me about 6 hours to install the entire shower system and run the Kerdi up the walls to 6 ft height.
I think the time and material to prep one of these shower systems is very reasonable as I expect the showers to last well after I have gone to my heavenly reward.
FYI, Bonsal is making the only thinset which Schluter has given their stamp of approval on for the Kerdi system. I think that they give a lifetime warranty if the installation follows their recommended guidelines.
sully
I am making a 4x5 shower
so I'd have too purchase the 72"x72" kit
$795.00 Not that bad, but I'd like too get closer too five or six.
If you just buy the materials, and not the kit, all you need is a drain, some Kerdi and some KerdiBand. (The KerdiBand is optional, but it's thinner and makes nicer seams than just using a stip of Kerdi.) For this unit, I just bought the smallest roll of Kerdi they sold on the online site where I got it. About $200 total.
Mike HennessyPittsburgh, PA
Edited 3/8/2008 6:01 pm ET by MikeHennessy
Hay thanks for the help.
"If you are using the old dry pack base system then why would you use the Kerdi?"
So you don't have to preslope and use a traditional drain. Using dry pack, you don't have to stick with the standard sizes/shapes.
Mike HennessyPittsburgh, PA
I use plastic and/or felt no matter what the board is.
if U are concerned with a double barrier ... I'd use felt.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
I used denshield on my tub in 2000, ZERO problems.
They use denshield on my jobs but have been using redguard over the dense sheild.
“The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.” —Albert Einstein
Edited 3/7/2008 8:04 pm ET by plumbbill
Dagwood,
there should be no vapor barrier behind the DS, but since this is an exterior wall you may want to cut the plastic and seal the inside corner studs, since you have compromised the sheet plastic that was originally installed. When you now install the DS you will be adding the needed VB by way of the DS facing.
Do not do a double layer VB.
according to the other, the product doesn't live up to its claims of being a membrane
BULL! I've been using DS since '94 with no problems , and I did check back over the years. I also did my own "experiment" , I put a 3"wide x 8" long piece of 1/2" DS into a bucket (8" dia. x 6" deep) of water covering the DS up 4", then left it there till the water evaporated, it took almost 3 mos. I checked the sample piece intermitantly along the way and at no time did the DS shows signs of "breaking down" or becoming spongy. It was as strong on the last day as on the first day. Also, I noticed that the DS didn't soak up the water much more than a 1/4"-3/8" above the water level, which would tell me there are less wicking problems with DS than with cement board, which does tend to wick moisture.
I seal all the seams with a silicone or poly caulk, as well as the heads of all the screws, I use 1 1/4" gal. deck screws to install.
Mike Hennessy's system looks like a good system for a shower location, most of my installs are in tub areas so I don't have the floor/drain areas to consider.
Geoff
P.S. In my installs I use 4x8 sheets, installing the 2 end (short) walls vertically and the long (5' ) wall horizontally. The cut-off from the short wall is usually enough to finish to the ceiling, since you are using the 4' on top of the tub. Costs about the same as using 3x5 sheets but leaves fewer seams for potential leaks. I seal along the top edge of the 1st long piece with caulking, then set the next sheet on the bead.
Thanks everyone for your replies. Being that this is my first time tiling, and that I didn't have access to the forums over the weekend, and the uncertainty over the product, I chickened out and got cement board. I followed the instructions in a home repair manual to put it up. I did replace the VB behind the cement board.It went up OK, and in spite of all the stuff I read about it being a PITA to work with, weight aside, it didn't present many challenges. I found that a $5 throw-away handsaw worked well for cutting the boards, and didn't create the clouds of dust that were forecast for cutting with a circular saw.I am now trying to figure out what to do about the window. I'll start another thread for that a little later on.View Image