This is my first time posting …so go easy on me.
I’m remodeling a shower room and was planning on greenrocking the whole room–the shower enclosure (36″ along two walls–in the corner) will be tiled with pretty standard 4″ square 1/4″ thick tile.
Can anyone tell me anything that would convince me that I should be using cement backer board for the tiled area rather then the greenboard?
cje
Replies
Water gets behind tile. Sometimes through the tile, sometimes through the grout. Sometimes through cracked tiles or cracked grout. Still, it gets through. It gets through in the worst installations, it will get through in the best of installations. The irony, s that the best installers plan for this eventuality and use cement board behind the tile instead of gypsum board.
Water will damage sheetrock. Water will damage moisture resistant sheetrock. Water won't do much at all to cement board.
Plan for the inevitable.
Tar paper over the studs. Cement board over the par paper. Tile over the cement board. Use thinset, not mastic. Detail it well and it will last.
Thanks for the info--an additional questiion --probably very basic--why use thin set for the tile instead of mastic?
cje
Mastic is organic and can serve as a breeding ground for unpleasant stuff. Also, if (or "when" as Mongo says) water gets behind the tile, it can re-emulsify the mastic. At least that's how I think my tile co explained it to me.
All above are absolutely correct. You can use 4ml poly behind your cement board if you'd like instead of tar paper. I find it difficult to work with. Remember to follow MFR instructions... thinset/alkalai tape cement board joints if called for (as with Durock). Remember to caulk all changes in plane on your tile installation (corners, coves etc), and you're off to the races. If this is your first shower you'd probably be better off with a pre-fab shower base unless you're especially handy and/or good with cement mortar.
Good luck!
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why would you caulk the changes in plane - wouldn't you just grout them like the rest of the tile--does the caulk provide a little more wiggle room if things shift/expand/contract or is caulk just a better waterproofer then grout?
cje
Structures move. Framing moves. Often times, the structure doesn't all move together. It sounds drastic, but I'm trying to simplify things.
If you grout the corner where two tiled planes meet...wall-to-wall, wall-to-floor, wall-to-ceiling, etc...the two planes will eventually, for some reason, move independently of each other. When they do, your grout will crack and water will get through that crack. Being the forward-thinking tiler that you are, you used thinset over cement board over tar paper when you did your tiling, so the water damage to the framing will be negligible.<g>
Leave a small gap between tiled planes. After you grout (and the grout has set up), use a tool to remove any grout that violates the free space in that gap. After the grout on the adjacent walls has cured, then caulk the corners.
Most grout companies have lines of caulk...both sanded and unsanded...that are color-compatable with their grouts.
and that goes for towel bars and soap dishes too.
as to why....it's your house right!
or......it's your customers house right!
Jeff Genius has it's limits.....but stupidity knows no bounds
don't forget to use the proper screws for the cement boards, not dry wall screws.
Tom
This may in fact be the first thread I have come across where I agree with all previous posters! You hit the jackpot CJ!
The only tid bit I might add....I like to fur out the wall studs with wood lath after tub / shower pan have been installed so that the cement backer board and felt paper overlap the lip of tub or pan. Theoretically if water gets behind tile and through backer board it will come down felt paper in front of lip rather than behind. Overkill? Maybe...but Id rather error on the side of caution.
Best of luck to you!
J. D. Reynolds
Home Improvements
"DO IT RIGHT, DO IT ONCE"
thanks for all your advice--I appreciate it
cje