Hardibacker Around Tub/Shower

[w9jim]

Working on tiling a tub/shower for the first time. The framing is terrible, but that's not my question. I'm wondering if the Hardibacker gets installed over the flange on the tub or just sits on top of it. The way the framing is, the tub isn't flush with the wall. Installing the backer to the top of the flange will help with shimming. Also, when I install the tile, it'll be flush on the backer and flow over the flange to the top of the tub. Thanks.

[jdm]

Jim --

You can do it either way. To bring the backer over the flange, it's necessary to shim the studs so that the backer doesn't bend out over the flange. You can stop the backer about 1/4" above the flange, letting the vapor barrier behind the backer come out over the flange. As long as the tiles are around 4" or more you'll have no problem letting the tile overhang the backerboard. You can fill between the tile and the flange with thinset. Leave a 1/8" gap between the tile and the horizontal surface of the tub, and fill that gap with caulk instead of grout.