Click image to enlarge.
1. Mark the tub wall lengths on the cement board
and score one side with a utility knife. Snap at the line and cut the
fiberglass mesh backing, just as you would with drywall. Smooth ragged edges
with the knife or drywall rasp.
2. Fasten the cement board to the studs with
special 1-1/4 in. screws (or 1-1/2 in. roofing nails). Keep fasteners 1/2 in.
from the edges, and install nailers in the corners if necessary to ensure
adequate backing.
3. Measure and mark the hole centers, then use a
compass to trace them. Cut the spout and shower head holes with a 1-1/4 in.
carbide-grit hole saw, and larger holes and curves with a carbide-grit jigsaw
blade.
4. Tape cement board joints with special mesh
tape. Mix a batch of thin-set mortar and cover the tape with one thin
coat.
5. Mark level and plumb layout lines. Evenly
spread several square feet of thin-set mortar with a 1/4-in. x 3/8-in. notched
trowel held at about a 45-degree angle. Shim the first row about 1/8 in. above
the tub to allow space for caulk.
