So, I was looking at a pile of boards trying to pick out one with no crown or bend to use as a ledger board to start my tiling on a tub surround.
Seems like five feet of dead straight wood isn't too common anymore.
Then it occurred to me that there might be a use for greenboard in a tub surround after all.
Sliced out a chunk of factory edge with my pocketknife. Put a little blue tape on the edges to keep down the crumbling and to keep the thinset from bonding to the paper. Screwed it up with a couple drywall screws in each stud and went to town.
Let things set up for a few hours and took it off. Worked great.
it may be old school, but I still like the look of good old 4x4 white tiles in a bath!
drywall is a GREAT idea for a ledger.
I seem to always have plywood scrap around so that's what I've used the last few times, seems most important to mix tiles from different boxes when doing shower walls if there is any size variation - shows up more on a wall where gravity is applying pressure to the spacers (last shower I did was 12"x12" with 1/8" spacers) as apposed to a floor where you don't have to worry about everything sliding down after you get it set!
Yes the fan is in an outside wall. The exhaust is routed down a foot or so before it runs outside. This provides an airlock to prevent warm air from charging out of the vent during the winter. You get a slug of warmer air trapped in the top of the pipe, and that nice -50 outside air can't rise up to spill in.
That may be why the contractor who built the house put it in the wall rather than the ceiling. There's not enough room in the truss above there to create a cold air trap in a horizontal exhaust run.