I have exactly 9" clearance between the new wall and the bolts of the flange for a toilet installation. The floor is a suspended concrete slab 4" thick, with both reinforcement and radiant heat copper tubing (I really would rather not attack the floor, but will if necessary). The wastepipe is cast iron. Access to the sealed crawl space beneath the slab (if I must replace the cast iron pipe) will only be through a masonry wall (brick leaf on exterior, inner leaf of concrete masonry units). I'm not anxious to do that either. So, options are: A. Treat renovated bathroom as a walk-in closet with sink. B. Buy an expensive 9" rough-in Toto toilet (if necessary, will do). C Demolish an inch from the newly re-plastered wall to create a niche for the tank, but that will mean losingthe layer of insulation and then, oh my, re-plastering the thing. D. Your thoughts? Any suggestions are welcome.

You said "new wall". Is this a new outside wall? The niche idea looks great, I just did one where they put the plate on the wrong side of the line and we lost 3.5". Take it back to the bare wall, insulate with urethane sheet foam and glue drywall over it. Put in a couple of glass shelves and call it an Architectural Detail" 12" rough in toilet works better than a 9 or 10.

(D)- Replace the toilet flange with a 1 or 1 1/2 closet flange and purchase a less expensive 10": rough toilet. Good luck, Tom