This was a modular house, I asked that the tub be shipped loose so I could tile then drop it in, but they foamed it in place. So I have to tile around it. They did put 1/2" Durock on the deck, but nailed it in (and didn't tape the seams, but I can do that). I pulled the cement board off the face/apron, plan on putting wood there. I had a whirlpool in the last house, bought unfinished cabinet doors built to size, that worked out well. I don't know if I'll do doors, sliding panels, piano hinge, or just T&B wainscot here but will do something wood. Thanks - I was thinking I'd rather have 12" tiles than something smaller, the less grout the better (though I may put in some mosiac as accents). What grit sandpaper? Will mastic be better than thinset? Since I have to buy thinset for the floor and the tub deck anyway? Oh, BTW, will you comment on my faucet/grab bar placement thread? Even with pulling the `1/2" cement off the face (and may pull the spacers off the 2x4s too), putting 3/4" wood back on will still make it a bit of a stretch with a 20" high deck, 3" ( or was it 2"?) high tub rim, and only 30" inseam. I'd like to cut the deck back another 3-4" but it's probably not worth trying to do it around the tub.

dorry, As you know, water can get past the tile and grout. Once it does, it'll hit the tile backer board. Cement board is an excellent tile backer board because it is not negatively affected by water. Wet it, dry it, repeat the cycle...and in 50 years the cement board will still look like cement board. Unlike a gypsum board, which will slowly turn to mush with repeated wetting and drying cycles. Now cement board is not waterproof. Wet it and water can pass through it. That's why you need some sort of drainage barrier in the wall. It's often done by stapling 6-mil polyethylene plastic to the studs, then lapping the bottom edge of the poly over the tub flange. Any water that gets past the tile/grout and through the cement board will hit the poly. The poly prevents the water from getting into the framing bays. Most of the time all will be well. The tile and grout shed 99.99% of the water down the drain. Any minor imperfections in the wall, the cement board might get a little bit wet. But think of the cement board as a sponge, it can hold a bit of moisture in it's pores. When the shower is not in use, any moisture that got into the wall usually evaporates back out of the wall. No big deal, no damage. Now if you had a damaged wall...bad grout, a cracked tile, etc...then you could get more water into the wall. If thee is more water getting in than can get out via evaporation, then the poly will stop the moisture from getting to the house's framing. It'll hit the poly and flow downward, over the tub flange, and back into the tub if weepholes were left in place. Poly is one type of membrane. Anther is a topical membrane that can be used on the face of the cement board. RedGard, Hydroban, etc. They get "painted" on the cement board, then you tile on the membrane. But as Bill wrote, any partial repairs leave you in an conundrum of sorts. Not sure if this is worth anything, but you mentioned greenboard. Greenboard as a tile backer in a shower has been a known poor building practice for decades. It has been an outright code violation since January of 2006. That's no help to you now, I know that. The big concern to address with your worker is the top horizontal seam of the repair. You'll have a seam in the tile backer, topped by a "seam" or grout line in the tile layout. A seam over a seam is an excellent point for flexure failure (cracks in the grout) and eventual water intrusion into the wall. Any issues will be compounded by there being nothing behind the tile backer to contain any water that gets back there. At a minimum, I'd remove the cement board and try to slide poly up behind the bottom edge of the existing tile backer, between the bottom of the existing tile backer and the wall studs. Even an inch will help. Enough to get some protection behind the eventual double seam. Then drape the poly down over the tub flange. Reset the cement board over the poly.

"... if tiling up to the ceiling above a soaking tub (without a handheld shower head), can you tile over established drywall that has Kerdi applied over the drywall." For the walls around a soaking tub, if you want to hang Kerdi on the drywall and tile on the Kerdi, that's perfectly acceptable. "I had also thought you cannot tile over drywall." In non-wet areas, you can tile directly on drywall. Example, bathroom walls outside of the shower, or kitchen back splashes. You can't tile directly on gypsum board in wet areas like showers and tub surrounds, even if the gypsum board is moisture resistant. In a wet area, Schluter allows Kerdi to be installed over gypsum board. In that case, the tile is on the Kerdi, and the Kerdi is protecting the gypsum board.

I suspect you will regret bamboo. I have stranded bamboo in a kitchen and I wouldn't put it in a bath. If you really don't have the money to truly fix the deflection, use a small mosaic tile, hexagon or penny-round will probably work best. Use a masonry board or a uncoupling membrane and then adhere the tiles with a flexible thin set. I prefer Laticrete 254, but if you have to do the big box store, Flex bond from Home Depot isn't bad. Then use a decent flexible grout. The Mapei flexcolor is a solid product. If your floor is flexing enough to break those tiles then you have much bigger problems. Eventually the grout might work loose but you should have quite a while before that becomes a real problem. ETA: Check my advice on the johnbridge forums if you would like. You can literally paste my advice to your problem over there and get opinions from professional tilers who will put their name and experience right there in their signature.