# Bathtub Installation - Expandable Foam or Concrete Base



## Jaret

A question on installing a tub, and if any of you plumbers out there do this.

I do know mortar is the way to go, but what about spray foam in up and around the sides? Or just regular insulation?

Thanks

J.


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## trick1

Concrete has always been the way to go, in my opinion. I wlso use a vapor barrier to protect the subfloor.


The spray foam expands (even the low expansion stuff) and can really make a mess. I'm not quite sure how well it actually supports the tub.


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## Plumber Jim

Concrete. never spray foam.


plumber Jim


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## WestCoastPlumber

I went with spray foam once, wish I never did, I felt like it was not that supportave, Lucky for me I wedged the rear legs with wood shims, and then blew in the foam.

I will always do mortar, with plastic under and between the tub


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## Jaret

Sorry, I guess want to take this question a different place. Was half cut last night when I wrote this. 

Mortar base yes, thats what I usually do, but I wanted to ask about insulating around the sides of the bathtub. Stuffing r12, or using spray foam the help reduce noise and retain heat. 

Is this something you guys have ever done. I do agree spray foam is messy. 

Thanks for the answers.


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## Hyper Piper

Mortar or non-shrinking grout.


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## WestCoastPlumber

Not around the sides. If they want to retain heat, I will sell them a cast iron tub. I don't think insulation is gonna help all that much.

If you mount the tub in mortar, there won't be that much sound at all. I also take it one step further and use a small piece of felt on the tile flange where I screw it to the wall.


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## Marlin

We use Structolite.


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## Redwood

Marlin said:


> We use Structolite.


Same here!


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## Protech

Closed cell spray foam works awsome but is very expensive


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## PLUMB TIME

Always use Jiff Set, a little more expensive, but when mixed with a paddle on the right angle very smooth and sets in 15-20 minutes:thumbsup:


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## SPH

we don't touch that part of it, up to the contractor.


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## plumb4fun

Years ago when I worked tracks we never put any foam or cement under the tubs. Just the styrofoam glued by the factory on the bottom, then shim the legs if needed and attach flange to studs.


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## 422 plumber

That's how I used to roll! Now whenever I do showers it's industrial. So I have the GC mix up some mud or crete and we set the bases in it. It's always on a cement floor.


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## Airgap

Kind of on topic, but when the insulators came and did my house a few weeks ago they shoved a bunch of batting around my shower and tub before I tied the drains in:furious:. The only benefit I can see with it anyway is sound dampening, not retaining heat. I appreciate what they were trying to do, but look first is all I ask. 
Oh, no foam, mortar all the way:thumbsup:


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## Goatee

Structolite and felt.


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## ASUPERTECH

Mortor Bed.... There are no other options!!!


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## PipeDreamer

Structolite when needed. We've used foam before but I don't think it's rigid enough. Once, on a remodel, we filled the tub with water, sprayed the foam and hit the road. Came back the next day to find the home owner let the water out, and the tub was 10" off the floor! It took hours to clean up that mess. That was the last time we used foam.


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## plbgbiz

Jaret said:


> ...insulating around the sides of the bathtub. Stuffing r12, or using spray foam the help reduce noise and retain heat...


The heat loss is primarily off the surface of the water. The insulation will help with noise. Best way to have a quiet tub is to install cast iron.


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## Tommy plumber

I have seen guys use expanding foam under fiberglass tubs and if they didn't fill tub w/ water first, it lifted tub off the floor. :laughing:


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## ranman

:thumbup: we had a sub working new condos for us. a long time ago.

he sat a jetted tub in pre mixed joint compound. it molded so bad the tub had to be removed. it was black.

I only use sand topping cement, mortar or no shrink grout


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## SlickRick

One of the other plumbers in town came by the shop and was telling me about a tub he had just finished on a remodel. The GC measured from the existing floor and set his framing where the tub would set flat on the slab. Well, he found out that the slab wasn't as perfect as he imagined. He had the plumber chip and grind the concrete until it quit rocking. It took @ 8 hrs. of pulling the tub in and out to set the tub. :whistling2:


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## user2090

slickrick said:


> One of the other plumbers in town came by the shop and was telling me about a tub he had just finished on a remodel. The GC measured from the existing floor and set his framing where the tub would set flat on the slab. Well, he found out that the slab wasn't as perfect as he imagined. He had the plumber chip and grind the concrete until it quit rocking. It took @ 8 hrs. of pulling the tub in and out to set the tub. :whistling2:



Hope someone gets some money for that. Makes me glad I am more into service, and remodel. I hear all these stories about G.C.'s and I just sigh.


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## plumbpro

slickrick said:


> One of the other plumbers in town came by the shop and was telling me about a tub he had just finished on a remodel. The GC measured from the existing floor and set his framing where the tub would set flat on the slab. Well, he found out that the slab wasn't as perfect as he imagined. He had the plumber chip and grind the concrete until it quit rocking. It took @ 8 hrs. of pulling the tub in and out to set the tub. :whistling2:


Ridiculous, I would have personally changed the framing the 1" required to set it right and used mortar under the tub. I always use mortar and have never had an issue, mortar is my friend, especially with some of the shoddy concrete jobs here.


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## Epox

Sand topping mix. Plumbers fault on the rocking Tub. It's our responsibility to install the plumbing fixtures correctly. Thats why they call us "pro"s'. If it was not right he should have fixed the problem then. Also on a different note. We install shower weep drains and pans and pack our toys and leave. That shower stall becomes storage for every other contractor on sight till the shower guys come in to set tile. They drop boxes of screws, materials, boards etc on the pan. Guess who has to own it if it leaks? We do. As a remedy to that,, during top-out inspection I have a standing test for the inspector to see,,,,, then have him note that the shower passed standing test during top-out inspection. Could save my tail later. Showers by upc code are plumbing recepticals. Sorry for getting off thread.


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## SlickRick

mpsllc said:


> Sand topping mix. Plumbers fault on the rocking Tub. It's our responsibility to install the plumbing fixtures correctly. Thats why they call us "pro"s'. If it was not right he should have fixed the problem then. Also on a different note. We install shower weep drains and pans and pack our toys and leave. That shower stall becomes storage for every other contractor on sight till the shower guys come in to set tile. They drop boxes of screws, materials, boards etc on the pan. Guess who has to own it if it leaks? We do. As a remedy to that,, during top-out inspection I have a standing test for the inspector to see,,,,, then have him note that the shower passed standing test during top-out inspection. Could save my tail later. Showers by upc code are plumbing recepticals. Sorry for getting off thread.


From what I was told. The GC installed the framing and that is the way he insisted that the tub be installed. How would that be the plumbers fault if the GC is paying to have it installed in this manner?


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## plumbpro

slickrick said:


> From what I was told. The GC installed the framing and that is the way he insisted that the tub be installed. How would that be the plumbers fault if the GC is paying to have it installed in this manner?


If I was not allowed to change the framing, you could be sure I was charging for every minute I was chipping and grinding concrete.


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## Epox

_From what I was told. The GC installed the framing and that is the way he insisted that the tub be installed. How would that be the plumbers fault if the GC is paying to have it installed in this manner?


With all due respect,,, I have yet to see a tub that was perfect on the bottom edge where it rests on the 1x4 etc. I have set tons of them. One most always has to custom in with shims, trim on the frame etc to get it solid and perfectly level both directions. Something is wrong with this picture if the plumber had no choice but install on what he's given and then be held responsible if it rocks. Think about it. We as "pro's" are required by law to get it right. But if so then okkkkkkkkkkkk. :blink:
_


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## SlickRick

mpsllc said:


> _From what I was told. The GC installed the framing and that is the way he insisted that the tub be installed. How would that be the plumbers fault if the GC is paying to have it installed in this manner?_
> 
> 
> _With all due respect,,, I have yet to see a tub that was perfect on the bottom edge where it rests on the 1x4 etc. I have set tons of them. One most always has to custom in with shims, trim on the frame etc to get it solid and perfectly level both directions. Something is wrong with this picture if the plumber had no choice but install on what he's given and then be held responsible if it rocks. Think about it. We as "pro's" are required by law to get it right. But if so then okkkkkkkkkkkk. :blink:_


Something was wrong with the picture, the GC. He controls the money. What would you have done under these circumstances?


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## Epox

SlickRick
Something was wrong with the picture, the GC. He controls the money. What would you have done under these circumstances?



Some GC's are unrealistic but the ones I have worked for are reasonable enough to know that like in this case, I did not install the frame that was so perfect I should have no problems. The framer did not know to verify the Tub would set right with the frame, and defenetiley the crowned floor is not the plumbers fault. The GC will typically want to know the fasted cure which I would say is to raise the Tub the 1/4" etc. or shimm as needed. Whatever to remedy the problem. If it entails a labor intensive floor chipping or grinding it will be extra and will possibly affect the tile layers etc. My bet is the GC would say raise the tub, and get it right. Not leave it rocking and go home. That's what made him mad and made the plumbers come back with chipper in hand. Thx Rick


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## SlickRick

I told the plumber the same thing. This was just a GC that I could not have worked with. And possibly had never framed for these tubs, and assumed he was right. Not understanding that the tub needed to be bedded.


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## Epox

Some GC's are real wonders. Typically good communication goes a long way with most. My first job for one GC started out badly, I was sent to plumb in a new 2 story home with full basement. Bout a million dollar home. I called my super at the time who relaid to him that the plans did'nt not match the actual floor layout. This GC stormed over thinking I was some idiot who couldnt read plans. Upon checking my plans he blushed and admitted these were an old set of plans. HIS fault not ours. We got along great from then on. If I see a problem I get on phone and get it right immediatly if possible. Thx Rick


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## RW Plumbing

mpsllc said:


> Some GC's are real wonders. Typically good communication goes a long way with most. My first job for one GC started out badly, I was sent to plumb in a new 2 story home with full basement. Bout a million dollar home. I called my super at the time who relaid to him that the plans did'nt not match the actual floor layout. This GC stormed over thinking I was some idiot who couldnt read plans. Upon checking my plans he blushed and admitted these were an old set of plans. HIS fault not ours. We got along great from then on. If I see a problem I get on phone and get it right immediatly if possible. Thx Rick


 See, this is the exact problem with most GC's. They assume it is YOUR fault without finding out. Some of them even try to blame you when it isn't your fault. Most seem to be the blame first find out after type.


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## CAPLMBR

*Mortar*

I use mortar, but not too soupy otherwise can crack apart. Not very many 2 stories out here, but never had a problem with support and if ample amount is placed like 1-2 five gallon buckets worth spread evenly usually does the trick. I have used spray foam but the problem with that is the expansion aspect and could raise the tub. If spray foam is your preference don't over do it and put too much and also be sure you have tub filled so as not to raise it then your basically teetering on the foam. As for insulation factor I would imagine it would give some insulation and sound reduction especially if using a fiberglass or pressed steel tub. Even though some tubs have either foam or wood supports integrated into the tubs do not rely solely on them to support the tub even with shimming. The evenly applied mortar will squeeze into all the nooks and crannies and not bowing or sagging and the tub gets locked in.


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## Miguel

slickrick said:


> One of the other plumbers in town came by the shop and was telling me about a tub he had just finished on a remodel. The GC measured from the existing floor and set his framing where the tub would set flat on the slab. Well, he found out that the slab wasn't as perfect as he imagined. He had the plumber chip and grind the concrete until it quit rocking. It took @ 8 hrs. of pulling the tub in and out to set the tub. :whistling2:


If it was me I'd have sent a kid in with a jackhammer to remove enough concrete to allow setting the tub as per usual and then bedded it in mortar. Same as any other tub. The only difference being that the guys doing the slab wouldn't have wasted time dikking around during the slab pour and the GC wouldn't have got the 2 hr + jackhammer "extra" invoice.

Btw, I'm a fan of using foam under tubs. The trick is not to try and dump all the foam at once! Just do a bit in the key areas... go and hook up the drain and start on the valve... then a bit more foam... go and rough in some other stuff and come back to finish the foam. With professional grade low expansion foam (skins over in 10 min and sets up in about 30 min) you can do a really solid job without the mess and cleanup of mortar. Very solid, too!


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## drsplumbing

1/2 of a 5 gal pale of joint compound works nice.


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## PlumbPowerHouse

Definitely concrete. We had to go back on some houses we did a few months ago and some of our crews were putting spray foam under the tubs and the customers were complaining of movement and creaking.


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## pauliplumber

A couple years ago I started working for a reputable GC that insisted I use spray foam under tubs. I didn't think it was a good idea, but figured I'd give him what he wanted. I have to say when I go back the next day or for the finish, when I step in the tub it feels like a mortar bed. Rock solid!!
As others have said, be sure to secure the tub in place and/or fill it with water, the foam _will_ raise the tub. I've used foam on over 20 tubs now without a problem, all very solid. I always use ample foam, usually about 3-4 cans worth. 

Those who say the tub base still made a cracking sound after the foam, the installers apparently didn't use enough.


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## Will

I prefer mortar(deck mud). I have done spray foam too if that is what the contractor wanted or didn't want to pay me for using deck mud. Works pretty good as long as you fill the tub up with water before spraying.


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## plbgbear

I've always used concrete or mortar. Only time I've used foam under a tub is when some other plumber did not get enough concrete or mortar under the tub and it was not discovered until the sheetrock and tile is already up and the boss did'nt want to tear the rock out to pull the tub up and out to redo it the right way. Other than that, concrete or mortar always.


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## stillaround

Since my opinion of GC's has jaded over the years...:
1. plumber is responsible for proper tub set...if a GC gets in the way and says do it in a less than proper fashion you have to say no....if you can communicate effectively then it will all smooth out
2. It is the plumbers responsibility to bring deficiencies( all except the ones we hide) to the attention of all pertinent parties....if it is a push come to shove scenario..end of relationship
3. Photos and journals are the way to go......otherwise its your insurance that takes the hit whenever it goes that way.
4. I set mine in sand mix or mortar or concrete with a plastic barrier...cheap and easy....

It still is amazing after all these years that a clear cut plan for a drop-in set, tile men, and framer ..there is no learned best way..still groping out there.
I tell the gc or homeowner that the deck gets tiled before the tub is set and the tile man must return to do the front after all is set and tested. If its clearly communicated then if they tile the front, I can SMASH it out and not get a backcharge.


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## Epox

stillaround said:


> Since my opinion of GC's has jaded over the years...:
> 1. plumber is responsible for proper tub set...if a GC gets in the way and says do it in a less than proper fashion you have to say no....if you can communicate effectively then it will all smooth out
> 2. It is the plumbers responsibility to bring deficiencies( all except the ones we hide) to the attention of all pertinent parties....if it is a push come to shove scenario..end of relationship
> 3. Photos and journals are the way to go......otherwise its your insurance that takes the hit whenever it goes that way.
> 4. I set mine in sand mix or mortar or concrete with a plastic barrier...cheap and easy....
> 
> It still is amazing after all these years that a clear cut plan for a drop-in set, tile men, and framer ..there is no learned best way..still groping out there.
> I tell the gc or homeowner that the deck gets tiled before the tub is set and the tile man must return to do the front after all is set and tested. If its clearly communicated then if they tile the front, I can SMASH it out and not get a backcharge.


I agree in every way. What gets me, you tell the tile guys to leave an access panel to pumps etc as per code. Many times I see them cut an area in the backer board out, screw it in place. then tile over the whole front. Useless. :blink:


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## futz

stillaround said:


> 1. plumber is responsible for proper tub set...
> 4. I set mine in sand mix or mortar or concrete with a plastic barrier...cheap and easy....


Absolutely. Your name is on that tub. If it screws up they're coming after *you* to fix/replace it. It's plumbing, so it's your responsibility to make sure it's right. You can't trust someone else to do it right (they won't) - have to do it yourself. 

I set mine squished into a topping mix (sand mix) bed. I've never bothered with any plastic barrier - I want that tub to stick to that concrete. Don't want it coming loose - I also shoot a full tube of PL Premium construction adhesive under there at all four corners if possible and mung it around with a stick to glue the tub to the concrete.



stillaround said:


> I tell the gc or homeowner that the deck gets tiled before the tub is set and the tile man must return to do the front after all is set and tested. If its clearly communicated then if they tile the front, I can SMASH it out and not get a backcharge.


For oval/round tubs I have my GCs and tile guys trained - I set the tub on plywood spacers between the tub and deck. The tile man removes them later and adjusts his thinset so his tile just supports the tub edge.



mpsllc said:


> I agree in every way. What gets me, you tell the tile guys to leave an access panel to pumps etc as per code. Many times I see them cut an area in the backer board out, screw it in place. then tile over the whole front. Useless. :blink:


Our inspectors here would go, "Where's the pump/valve access? Show me or I reject the final inspection." Since jet tubs are totally out of fashion these days all I usually have to worry about is service valve access - I've taken to piping them in the back of a nearby vanity so I don't have to worry about tub access anymore.


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## Cal

Mortar on concrete . Thinset on plywood .


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## bigdaddyrob

Structolite, with plastic down. On any of my own work. Cast Iron to retain heat<or just bc i like them< lol

Trac work is always fiberglass for halls/basements and drop in for the master. Its understood on those jobs, get with the builder one time at the start of the job and ask how he wants to handle the deck issues we will face in every same model home bc the mexican sub crews will always build it differantly. And then the we set acording to there wants/needs. Most of the time the just want the backs square to the wall bc they now they will have to fix the front. and the hieghts always change. Some request on deck/ other off for tile to be slid under. Its always a sad joke what we have to do to secure these.

Panels for motors are normally caulked in tiled panels. Cut the caulk and slide out with a putty knife. Mixixng Valves in cabinet or basement. Never behind panel


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