Tub flash

[pegasush]

Not a critical waterproofing item, but an irritating problem.

At the top of tubs and showers there is a flange, intended to go under the drywall. Of course, installing drywall over the flange typically flexes it, so the boarder runs to the top of the flange, and the taper fills the flange with mud, and the joint is caulked after painting. Done properly, this looks fine when new. Unfortunately, drywall and mud are not very compatible with wet places, and the paint will peel up, the drywall paper will peel off, etc, etc.

I have seen (installed) a strip of material, about 3" wide, full length of tub, across ends and down 2 front joints. This looked like tile, but I have found no tile anywhere near 5' long. It may have been some acrylic product, but again, can't find it.

If a house had some other areas tiled, I would set 3x3 tiles around these tub joints, but I would like to have a standard solution to this area for houses without any tile installed, where I do not want a tile installer on the job. Does anyone know of a supplier for something like this, or is there a better solution?

[giddonah]

I don't use drywall, I use hardibacker. My friend says if he were doing a bathroom for just himself and nobody else (i.e. no woman :wink: ) he wouldn't even paint the hardibacker. Then just silicone the bottom.

Edit: of course, we tile over the hardibacker, but nobody says you can't paint it.

[Tom R]

Once the shower unit is in, - - pack out the framing above (and alongside, if necessary) the flanges with 1/8" strips, - - then just drywall normally. To get a nice, crisp edge, - - flat-tape the bottom and side edges of the drywall where they meet the shower unit.

[Sweep]

The method I have always specified and I believe is still recommended by the Tile Councel of America (hope I'm not out of date) is to bring a cementitious backerboard down just short of the flange but not over it or touching it (to avoid wicking moisture into the wall). Ceramic tile (or whatever) then overhangs the board slightly and the joint between tile and tub is filled with silicone sealant (vinyl caulk won't work here). If you use water-resistant wall board it is best to use an uncut edge against the tub flange. If the tub has a shower, the life of the installation is greatly increased if at least the bottom half of the wall has cementitious backerboard. If you are asking how to seal this joint without a water-resistant finish applied over the wallboard, I confess I have no idea and can't imagine gypsum wallboard lasting very long in a shower without being protected. As you stated "drywall and mud are not very compatible with wet places." I don't think I really understood that part of your question.

[pegasush]

Sorry, I wasn't exactly clear. The 'tub' part of the tub or shower really refers to a one-piece tub/shower unit, so that the drywall to tub joint is actually at the top of the tub-surround.

Tom's solution is similar to the standard contractor method here, except that it is rare that the 1/8 furring is ever added. Occasionally, this does get wet, though, and eventually the drywall will deteriorate along the joint.