Hello I’m installing a fiberglass (36″x36″) shower pan on a concrete floor. The manufacturers directions suggest using 20lbs of joint compound. I tried it (set the base in 20lbs of joint compound) but found 1) it wasn’t nearly enough to support the entire base and 2) it seemed to have high and low spots. So, I decided to pull it up and start over. Does anyone have a suggestion as to the best hardening agent to use?
I never did put anything under bases I set, You could measure the high points in base and put that much sand on fl. and wiggle it down till it touches fl. You could pour the hollow spots in base with cement and let set a couple days and turn it up and set it.
I agree with Dunbar. Get everything ready to go (drian connection, etc.) and lay the acrylic or fiberglass pan on a fairly stiff but still workable bed of mortar that has been carefully leveled and framed out on the subfloor, and you will wind up with a solid installation.
“Joint compound” may be easy to use right out of the can, but mortar really works best.