wwhitney
In the Trades
Overlapping is the better practice, and it's not that hard to shim the studs. And the installation guide currently linked to from the product webpage at Kohler says to overlap.I now see two different installation guides. One says backer board goes to lip. Another says to shim to lip. I'm gonna go ahead and say the backerboard goes to the top of the lip, not overlapping it.
A 32" wide receptor would be nice, but I guess that's not an opton. I favor cutting the tile and placing the receptor on the subfloor unless the solution you have for the receptor/tile transition works just as well with it lifted up. Which it definitely may.I was thinking that and putting some sort of white bullnose around the bottom if I built the floor up. Then again, if I put the base recessed I'd still be doing that anyway. Do you have another suggestion?
That receptor/tile transition is definitely the hard part. I favor putting the receptor against the existing framing, and building the new wing wall out to at least as far as the existing tile. That leave an ~2" gap between the existing tile and the receptor, but only one edge, between two side walls. My first thought would be to find a matching size tile. If the color/finish is a great match, just fill in the area, removing any existing cut pieces. If it's not a great match, go with a contrast and fill in with a pattern/accent strip.
Another option would be to cut the tile in place a constant distance from the edge of the receptor, and install some coordinating rectangular tile in the gap.
On the other hand, furring out the back wall 2" to punt on filling in the tile has some attractions. I might just set the receptor first, then set notched 2x6s to sit on the bottom plate and sister each stud, providing the alignment required for the tile backer to overlap the receptor flange.
Cheers, Wayne