Foam Board + Hydroban
I'm working on picking the right backerboard for my project. I have a 32" x 60" MTI alcove tub with a flange that is ~1/2" thick. I've had good experience with durock + redgard but am looking to try more modern methods and products.
Because my tub flange is almost 1/2" thick, I plan to use adhesive to attach a banding product to the tub flange and backer board. I also plan to build a custom niche out of whatever backer board I choose. Hydroban was attractive because they sell compatible banding + flange + liquid products.
I'm not a big fan of kerdi board or laticrete hydro ban board due to the flexibility they have. Goboard is pretty stiff, albeit a bit itchy. I really like wedi or similar products like sentinel (Floor and Decor brand now owned by Wedi) / kbrs / prova. Wedi is stocked locally and has the added benefit of coming in several thicknesses, giving me flexibility for furring out the walls or matching up with 5/8 sheetrock.
So ideally, I'd like to use wedi or sentinel with hydroban band at the tub flange, and roll-on over the seams and in the niche. This isn't an "officially" supported combo by either hydroban or wedi. On the other-hand, goboard does support thinset + taped seams with liquid waterproofing applied.
Would I be fine to use a liquid membrane over a cementitious-faced XPS foam board like wedi or sentinel? If I went that route, should I use thinset + tape for seams instead of polyurethane sealant?
Or instead stick with goboard where it's an approved combo, or old fashioned cement backerboard?
sealant is fine between the sheets. Hydroban and Nova do NOT USE THINSET. Your corners should already be solid, not needed any of those products for stability.