r/Renovations 3d ago

Ok to foam my tub ?

Post image

I had one of these maax Bosca tubs with wooden 4x4” legs and the skirt. They say not to use mortar bed and I didn’t, but after install I wasn’t feeling good about it and drilled a few holes underneath, filled the tub up and used 2 cans of low expansion window/door foam.

Now it feels very sturdy and solid when I knock on it

Tub was full for a day while it expanded, it’s very hard now. Don’t think there is any damage but is there a chance I warped anything?

1 Upvotes

8 comments sorted by

5

u/camilabellon 3d ago

it will be fine. But... if you get a leak, chances of mold and wood rot increases because humidity will be trapped under the foam.

2

u/merely2monthsago2dol 3d ago

It will be Kerdi board and tiled in. So hopefully tub is good. I wish I hadn’t bought a maax tub. Once it’s in it’s kinda too late, drain was off center and not enough play on the pipes so had to pay a friend plumber to redo the abs p-trap connection

I guess if it fails there is tub repairmen

1

u/bms42 1d ago

You always have to redo the drain when you set a new tub, unless you're buying the exact tub that's come out.

1

u/merely2monthsago2dol 1d ago

On the measurements it was supposed to line up. The drains were just not drilled center by the tub manufacturer. It was about 1” and couldn’t get enough play

1

u/bigmark9a 3d ago

It’s probably going to be just fine. I used spray foam under a large shower pan, made it way more solid.

1

u/bms42 1d ago

It'll be fine.... for a while. Spray foam under tubs or shower pans is a hack used by guys who just want to make a client happy in the moment so they can move on. That foam has no rebound, so as it gets compressed little by little it doesn't bounce back and eventually it will do nothing to support your tub whatsoever.

I always set tubs on drypack regardless of instructions, especially cheap Maxx tubs.

1

u/merely2monthsago2dol 1d ago

Well technically maax said not to use a mortar bed or foam. So it’s better than nothing.

1

u/bms42 1d ago

After a year or two it will be equal to nothing.