Discovered a tile shower has failed while rennovating my kitchen (shower backs up to the kitchen). Removed the kitchen drywall, treated all surfaces, made sure everything was dry and hung greenboard. No structural damage. Now have to fix the bathroom before using it again.
What’s the best way to prep the new bathroom so water will _never_ get behind there? Don’t want any chance of things getting wet back there in my lifetime. Is there a waterproof membrane which can be applied behind the backerboard? Other ideas? House was built in the late 70’s w/ plaster 1′ above the tub and drywall from there to the ceiling. Want to do it better this time.
This is low priority as the kitchen needs finishing first, but want to begin planning.
thanks,
john
Replies
Use Wonderboard or any CBU but I happen to like Wonderboard in "wet" areas.
Before you screw the CBU's to the wall be sure to put up some 15# felt to keep any water that may leech through the Wonderboard on the shower side of the studs.
I've lived with this application in many houses for many years with zero problems.
Good luck
Be well
andy
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Thanks, Andy.Just be clear, felt against the studs, wonderboard over that?john
Use 30# felt if it'll let you sleep better..and yeh between the studs and the CBU and once again. I like Wonderboard. Why? Because try at HD to lift a sheet of that and any other CBU they have there. Also it can be used "outside" ...also...when I was doing a job on my own house a ways back I had a large piece sitting in a spackle bucket of water. Probably was sitting in there in my yard for three months. When I took it out it was still like new when it dried off.
I know some guys here think its overkill but...I always add a liquid latex mortor additive to my thinset (be sure youre using the right thinset that allows you to use a LLMA....its the bag that costs less than the ready mixed powder ). "I believe" its better than the stuff that says you don't need to use any. It sort of gives you another layer of rubber/latex between your tiles and the CBU. I also go for the overkill in real wet area like shower stalls and put a paper thin layer of thinset on the back of the tiles aka backbuttering to give my tiles
ONE HUNDRED PERCENT adhesion...I've played with stuck tiles of scrap that had the additive I mixed in and the thinset that has it already mixed in it which convinced me adding your own LLMA is better..just call me the overkill kid
BE well stuck
andyView Image
Andy,
Just a quick question or two. We're about to put in a tile shower in our vacation home sometime next summer. One of the shower walls is an outside wall. The stud bays in that wall have insulation and a vapor barrier (plastic sheet) stapled to the studs. Can the plastic vapor barrier be used in place of the felt? Also, I had planned on putting 1/2" plywood on the shower walls followed by the CBU. From what you say, it sounds like the 1/2' plywood isn't really necessary. Is that correct?
ChipTam
Can the plastic vapor barrier be used in place of the felt?
Yes, but be certain that there are no custs or holes in the plastic. And note that an additional layer of waterproofing material will not cause problems, and will be cheap insurance. I'd use both the existing plastic, and whatever other barrier I was using in the other three walls.
Also, I had planned on putting 1/2" plywood on the shower walls followed by the CBU. From what you say, it sounds like the 1/2' plywood isn't really necessary. Is that correct?
As a general rule, the plywood is not needed. The CBU is sufficient to hold the tile, and be a sturdy wall.
But note that if you have any plans (or future needs) to put grab bars in the shower, they need to be anchored into the framing, or into structural wallboard that spans the framing. CBU is not strong enough, and neither is 1/2" ply IMHO. You'll need 3/4" for that.
Unless you're the lead dog, the view just never changes.
Many thanks for your reply to my questions.
ChipTam
Treat the CBU with 2 coats of Laticrete 9235 with fiberglass mesh in between. Set it and forget it. I could make a boat with that stuff.Regards, Scooter"I may be drunk, but you're crazy, and I'll be sober tomorrow." WC Fields, "Its a Gift" 1934
In No Calif, if you want waterPROOF, setters are using a CPE like Dal-Seal TS as a membrame.
Same technology as memebrame under the mortar bed for the pan.
Easy to install, a little pricey, but waterPROOF.
Yeah, Doug, I'm familiar with it, and it is good stuff.One advantage to a latex type membrane is that it conforms to corners and curbs better. A second advantage is that at least in my experience the two layer laticrete forms a monolithic structure under the tile which moves, expands, and contracts in unison, so I grout corners and plane changes instead of caulk them. It like floating a wall out of mud in that respect.Regards, Scooter"I may be drunk, but you're crazy, and I'll be sober tomorrow." WC Fields, "Its a Gift" 1934
But note that if you have any plans (or future needs) to put grab bars in the shower, they need to be anchored into the framing, or into structural wallboard that spans the framing. CBU is not strong enough, and neither is 1/2" ply IMHO. You'll need 3/4" for that.
Make plans for that by installing blocking between the studs to accomodate future grab bars. Then you can install the CBU over the blocking.
And snap digital pics with the dimensions from known reference points visible so you can install things more easily.
My frameless shower glass guys loved the pics of all the blocking. Saves a lot of headaches.Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
No, don't put the plywood behind the CBU. The CBU will let water thru and the plywood will rot. If you put the ply behind the Vapor barrier you're O.K.
I too am installing a new bath and this discussion has been helpful. However, I would like some advice regarding how to detail the connection between the tile backer board and the tile flange on the tub. I am using an American Standard Americast tub and the tile flange is approx. 3/8 inches thick. The instructions say to shim the backer board out over this flange but I hesitate to shim out the entire wall that much since the tub will sit at the corner of two large fully tiled walls and not just in an alcove.
The instructions say to shim the backer board out over this flange
There's your answer. If you choose to follow it or not is up to you.
The reason is, how else will water that makes its way to the backer get back to the tub where it simply goes down the drain instead of soaking the framing below the tub? That's the entire reason water barriers are placed behind the backer and lap back into the tub. It's not to protect the walls, it's to protect whats below the tub.
Had a tile guy not lapped the backer and water barrier into the tub there's no question that we'd have them tear it out and rebuild. There's no tile, tub, or other trade association that would defend such a practice.
Beer was created so carpenters wouldn't rule the world.
the tile flange is approx. 3/8 inches thick.
As a follow up, there isn't any reason why the flange can't be recessed 3/8" into the studs so no shimming of the walls is needed.
Beer was created so carpenters wouldn't rule the world.
Greenboard is not suitable for a tile shower. Do what Andy says, or install Kerdi over the drywall for a waterproof installation. You can get help at http://www.johnbridge.com
Billy
Thanks for the info. Greenboard was installed in the kitchen which backs up to the bathroom. I haven't even started tearing the olld shower out yet...
Install a fiberglass surround. Or use a rubber membrane. Anything else will allow SOME moisture through, though the amount is trivial if the gods are in your favor.
happy?
the absolute best and final solution is Schluter. You dont even need greenboard, Durarock or similar materials.
The material is installed with thinset, it has its own waterproof membrane build in and it is easy to work with.
check http://www.schluter.com browse to shower installation. It has an installation video which you can download