setting a tub

rosiw

A question and hopefully somebody can answer ... my building contractor is replacing my tub due to a crack that formed in the fiberglass (I believe due to improper setting). So when I expressed my concern about how the new tub will be set they indicated that they were going to use a spray foam to set the tub in ... this seems odd. How can that foam withstand and stay firm when water fills the tub ... it seems that over time foam will compress.

Any comments or thoughts?

redline

Depending on the size usually use a bed of mortar.

majakdragon

Your thinking is correct. The foam will compress over time. I have yet to see a tub manufacturer recommend, or even suggest, using spray foam. Most I have seen suggest or require a mortarbed. For a tub, a 5 gallon bucket of premixed mortar would probably be cheaper and better than the foam.

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rosiw

thanks for your help ;-)

troubleseeker

We always support the tub along any wall by nailing a ledger to the studs under the flange of the tub, and also as suggested, setting the tub in a bed of mortar. If it is a wood subfloor, put down a layer of felt paper under the mortar. Nix the foam idea, because the type of foam that will be firm enough to offer any support, will also be high expansive and most likely lift the tub when it expands to cure.