Builders–what do you do differently from the traditional tile shower with a steam shower? My understanding is a traditional shower goes like this: Pre-slope deck mud, membrane up to 12″ of walls, more deck mud, then tile, CBUs on walls, then tile. But doesn’t the TCA calls for all surfaces in a steam shower to be covered with a vapor barrier?
I have no vapor barrier between the CBUs and the studs. Two of the three walls are outside walls constructed of SIPs, with the CBU directly fastened to the OSB. In tearing out a closet wall opposite the shower, I see water wicking up to the membrane edge, then wicking up further where the studs contact the CBUs. A stick built house might be able to work off the moisture, but for an OSB-foam-OSB sammich, water is getting into the OSB.
I have some drywall failure next to the shower that indicates vapor is getting under the drywall. This would mean the steam is getting under the tiles and CBU, hitting the foam and coming back out through the drywall. See pics.
Builders, what would you do? What is your practice?
Replies
The "funny bumps" looks like nail pops.
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
I have nail pops around the house, and none of them looks like these. The cross section is concave, with a small "x" crack in the middle.
need vapor barrier overlapping membrane vapor barrier goes all the way up walls, any new courses overflashing the lower one.... vapor barrier on ceiling overflashing the wall vapor barrier ... any steam condensing up top can roll all the way to pan w/o leakage to studs w/steam, CEILING needs tile, too
in your case, i would not have attached underlayment directly to SIPs, even with a vapor barrier would have firred out, maybe 12"o.c. on OSB, then vapor barrer followed by hardibacker, etc. w/steam, extend concrete board past wet surfaces beyond where it's required, mud those joints w mortar, not gypsum cheap insurance againt steam traveling to sheetrock/gypsum joints
can try using a good sealer on tile and grout, though that's a band-aid now IF ceiling is not tiled, try doing that and seal all
"I'm not responsible for my actions."
How standard is this method? I am going to check the tile handbook when it arrives. Unfortunately, no sealer is going to fix this.
yup, the sealer is a band-aid at best, suggested it as a stop-gap until you can do a proper fix
sleepers on the SIP'S w vapor barrier over them allows condensate on the back of the vapor barrier a place to dry out also for minute amounts of leakage or condensate that "wicks" on fasteners that penetrate the barrier i've demo'd a few tubs and showers w vapor barriers and found small water stains (but no rot) on the face of the stud where the staple or roofing nail perforated the barrier
i still use tarpaper, 30lb. w staples for a barrier old tech but it works spare the staples attaching it use what you need, smear a little tar on 'em before the cbu applies also skinny bead in corners where felt was creased, as it "cracks" when folded and needs sealing not supposed to use membrane as a vapr barrier, i'd skip the expense of kerdi felt works on SIP's i'd fir out sleepers 12"o.c. for better support, glue & screw put some strips where horizontal seams will lie i do blocking under seams w stick built and screw the hardi into it for strength saw your pictures, definitely some leakage or condensation
someone mentioned sealing the overflashed areas good idea for steam, not needed w/o steam use a bead of roof tar from a caulk cartridge another good idea is the SS screws dedicated screws for cbu's suck, heads don't countersink, create lumps that have to be reconciled to get tile to lay flat countersink SS screws to get a flat wall but don't gun them through
"I'm not responsible for my actions."
Thanks vinnie--Seems the consensus here is using a vapor barrier. It is quite astonishing to me that when I pursued this with people involved in the construction, they all say one of the following: Vapor barrier not required, CBU is a good vapor or water barrier, or "Huh, never seen it done with a barrier". This involves the building inspector, the architect, the tile setter, and the builder.I have a theory that the CBUs were set on or into the mud bed, which allows the water to wick up to the wood. When the OSB on the SIPs gets wet and expand, it allow the steam to pass through to the oustide, under the drywall, then it comes up at the weak points.
sounds like a tearout in your future this is good, it spurs the economy vap. barrier is cheap easy insurance don't know why anyone wud fight using them, especially in shower w steam "I'm not responsible for my actions."
Ha ha...guess the only bright spot about this do-over is that I still have the builder on the hook for his warranty. I hate to think what this will look like a few years from now.
Cement board will not fall apart when it gets wet, but by no means is it a waterproof barrier. When I do a shower the stud walls all get covered with 30lb felt and the board fastened with ss screws.
Absolutely, I don't think the CBUs will fall apart. Just concerned with it screwed directly to the OSB w/o a vapor barrier.
Steam showers need a continuous vapor barrier.
Not just a drainage plane like lapped tar paper...but a vapor-tight barrier, all seams sealed. Floor/walls/ceiling all tight as a drum.
Some topical roll on membranes are not rated for use in a steam shower. Often times it's best to bring the barrier as close ot the tile as possible to eliminate deep wetting of the substrate (cbu on walls and mud on floor).
Best bet these days is Kerdi membrane. Pretty much bullet proof.
Your existing shower is built incorrectly. Not just for steam, but even as a regular shower. You need to have some sort of barrier (lapped felt or 6-mil poly) between the CBU and the osb.
No barrier in a steam shower is nothing but trouble.
Steam showers also have a sloped ceiling, minimum 2" pitch.
Here's a link to a Kerdi shower in the photo gallery:
http://forums.taunton.com/tp-breaktime/messages?msg=86714.1
Mongo
Yeah, I am a Kerdi convert myself. Just wish I had known about this before building the shower. Checked with building inspector today, he said they do not require a vapor barrier (!), just CBUs. Thanks.