Shower is a Pittsburgh Corning glass block walk-in. I hate shower
doors—scum factor 9—so no door on this one. 15# tar-paper
goes on the floor, then the one-piece fiberglass pan sits on a bed of
mortar on that and is nailed to the wall studs with SS ring-shank nails.
Strips of 15# paper cover the wall studs, then ½" tile-backer sits
on the nailing flange and goes to the lid, attached with #6 SS screws
through pre-drilled and countersunk holes. You can only get 3'×5'
tile backer here in Cow Town, which was fine for the short side but
the long side would have been better with 8' sheets. OTOH the stuff
is very heavy and I would have had a hard time installing 4'×8'