[mgh-pa]

I'm going to be starting my bathroom remodel here shortly, and while I haven't purchased the tub/surround, I know what make/model I'm using here.

Reading the installation instructions, they are a manufacturer who actually does recommend setting the tub in a bed of mortar mixture for leveling. I have no problem this this, other than mess and the tight space I'm going to be working with, so here's my question.

While it's not mentioned in the manufacturers recommendations, can non-expandable spray foam be used as a leveler? I couldn't find much on the topic other than the recommendation of NOT to use the expanding foam for obvious reasons. My main concern, aside from it not being listed in the manufacturer's recommendation, is the fact that I don't believe foam is a load bearing/support product, correct?

Secondly, the manufacturer mentions using a felt pad if provided in place of the mortar bed. What is this? I've never heard use of a felt pad for a leveler.

Again, feel free to slap some sense into me here if necessary. :thumbup:

 

[ddawg16]

Good question.....I don't know if I have the answer....but.....I used the foam on our fiberglass tub when I installed it.

Since the tub is above floor level, I made a platform that followed the slope of the tub. There is about 1" between it and the tub. I then used the spray foam......expanding spray foam. The next morning the tub was sitting about 2" above the frame.....ooopppsss...

So...I cut out the foam (pretty quick just using a hand saw)...cleaned everthing up...tried it again...used less foam and this time I filled the tub about half way with water. I came out right this time.

Now....with that said....is that the best way? I don't know. I'm interested to hear input from the experts. Joecaption? OhMike? Jaz? I'll be doing my wife's new bathtub in about a month or so....

But I will point out that it's been about 8 years now since we did it....I don't see any flex in the bottom....nice thing about the foam...it's 'warm'...and quiet.....as when the kids drop toys in the tub.....

 

[joecaption]

I would not do it, for one if it ws such a good idea why would the manufacture not suggest it, as you mentioned it's compressable so a void may form, taking the risk of it lifting as it cures, expecive if you bought enough cans to completly fill the area. I'm sure there's more.

I try to buy a better quality tub or shower that's sellf supporting or come with a foam block that the whole thing sits on that's preformed.

 

[mgh-pa]

I would not do it, for one if it ws such a good idea why would the manufacture not suggest it, as you mentioned it's compressable so a void may form, taking the risk of it lifting as it cures, expecive if you bought enough cans to completly fill the area. I'm sure there's more.

I try to buy a better quality tub or shower that's sellf supporting or come with a foam block that the whole thing sits on that's preformed.

Any recommendations on a tub/shower that would meet those requirements?

 

[troubleseeker]

Use the mortar, mixed to a consistency so that the weight of the tub can squeeze it flat as it settles in. You don't say what material the tub is, but this bed is to provide a solid, flex free support for the bottom of the tub, especially important for fiberglass , acrylic, or light weight steel tubs.

 

[carpdad]

Foam degrades as time passes.

 

[paintdrying]

I knew a plumber that would use drywall compound under everything. I would just use the mortar mix and be done with it.

 

[oh'mike]

Masons mix--right on the plywood floor---set the tub --wiggle it until into position secure the flange to the framing and leave it alone until set.

Do NOT step into the tub to set it--you might over do it--causing a hollow under the tub---

Gypcrete also works

 

[COLDIRON]

Foam degrades as time passes.

"Not if its kept from sunlight"

 

[COLDIRON]

I used expanding foam under my shower about 10 years ago no problem.

Now if I was going to install a bathtub I would probably use non shrink grout, or foam. Non shrink grout is what it says, once it sets that's it no shrinkage.

 

[troubleseeker]

I knew a plumber that would use drywall compound under everything. I would just use the mortar mix and be done with it.

I don't have much faith in the mud, but it is actually the recommended base in the instructions of a few acrylic tub manufacturers. Maybe there is a concern about the corrossiveness of cement based product? I still use the morter.

 

[BigJim]

Masons mix--right on the plywood floor---set the tub --wiggle it until into position secure the flange to the framing and leave it alone until set.

Do NOT step into the tub to set it--you might over do it--causing a hollow under the tub---

Gypcrete also works

What is Gypcrete? Which would be best, the Gypcrete or Mason's Mix?

 

[rossfingal]

gyp-crete (flo-crete) -
something like "floor leveler".

I'd use mortar.

"RF"

 

[oh'mike]

Ross is right----you would use Gypcrete only if you had a bag on the job for something else---

Otherwise masons mortar is the best choice

 

[mgh-pa]

Thanks, guys. I appreciate it. I will go with the mortar mix. No reason to take unneeded risks.

 

[wrongdave]

Thanks, guys. I appreciate it. I will go with the mortar mix. No reason to take unneeded risks.

Yeah, it costs next to nothing and is easy to do, hard to not do that.
When I did my tub about 10 years ago, the manufacturer didn't recommend putting anything under it, but I used a combination of mortar and spray foam anyway. I think I put them in alternating rows under the tub. At the time I'm sure I had come up with some logical reason for doing that, but I honestly don't remember.

Anyway, worked out great, solid tub 10 years later.
BTW, my tub was a combination of a thin steel layer over some thick lightweight composite. Feels like a cast iron once it's installed, but it was light enough I could install it by myself. Turned out to be a great choice as it has held up well.

 

[mgh-pa]

I never mentioned it, but I'm going with a Sterling Accord tub/shower combo. Made of Vikrell material (assuming it's just a type of acrylic), so it makes sense why they recommend the mortar bed.