What to do about the gap between the tub and the studs?

Question

I had a plumber help me install the bathtub in my bathroom today. Next step is to install the cement board. When facing the tub directly, The tub butts right up to the studs on the back (long side) of the tub but I’m left with a 1/2” gap on the left hand side of the tub and a 3/8” gap on the right hand side between the tip lip and the studs. What should I do to address the gaps on both sides prior to installing the cement board? The cement board is 1/2” durock.

Answer 1

Assuming that you don't own a table saw, Home Depot sells 5/16"×1-1/2" lath. That or you can use a circular saw to cut strips of whatever thickness of plywood that you need.

You should replace those screws with stainless steel screws. Wedges at the screw locations are a good idea so that the screws can draw everything tight.

Answer 2

Shims between the tub and the studs.