Leveling a tub in a basement

[blazenut]

Im installing a bathtub in my basement and had a question regarding leveling the tub. The floor where i am going to install it isnt level (probably off by 1/4-1/2" from wall to front). Would you guys simply level with plastic shims, or would you level the floor first with a floor leveling product? Since i am going to tile the floor, im thinking that leveling the floor would make more sense, but i wanted to run it past you guys first. If you would level the floor, what product would you use? Im getting mixed information with all my searches. Any information or links would be greatly appreciated. Thanks.

[John Kogel]

If it is a standard Metal tub, it rests on the floor only along the front edge. The side along the wall hangs on the wall, so leveling the floor under the tub would be unnecessary. It is important for the tub floor to slope towards the drain, so that is where you need to check when you install it.

As for the rest of the floor, I would just use the tile thinset to take up the dips in the floor, and 1/4" won't amount to much if you correct for it with the thinset.

[Richard Moore]

I have never used or needed a floor leveling compound but, if I had your option of doing the whole empty room or trying to level neatly up to an installed tub, I would definitely go with the former.

As for the product to use...if you are buying the tile from a tile/flooring specialty store I would follow their advice. If from Depot de Maison, well, maybe someone else can help you.

[blazenut]

I was unclear... I was never going to level the whole floor, just the area that the tub is going to be installed. I thought that would make it easier for tiling the floor. I wasnt aware that only the front edge touched the floor (never installed a tub before).

[John Kogel]

Yep, you want it to be level or sloping slightly towards the drain, but never the other way.

I have better pics somewhere, but here are some pics under a mobile home tub. I saw the opening behind the water heater and got some graphic rodent dropping shots. They had the wallpaper and vinyl flooring in ahead of the tub. This one has enough clearance for a trap. Usually, the trap has to go below floor level. But that is a typical underside view. A 2X4 goes along the wall to support the wall flange. That 2X4 needs to be positioned at just the right height and it needs to be level.

Click to Enlarge

34.67 KB

Click to Enlarge

63.54 KB

Oh, and a tip about tiling the floor. I have found the last two floors I've done in my place, the 13" tiles fit perfect with no cutting between the tub and the cabinet. A 6' X12' entry way, 13" tiles, same thing, no cutting. []

[Richard Moore]

I was unclear... I was never going to level the whole floor, just the area that the tub is going to be installed.

OK. Then I think you have to use shims or you would have a lot of weight right on the edge of the leveling compound, which would probably just crumble. Be sure to allow for the height of the shims when installing the rear ledge support stringer.

And, as we always tell our clients, RTFM!

[Bill Kibbel]

If it is a standard tub, it rests on the floor only along the front edge. The side along the wall hangs on the wall, so leveling the floor under the tub would be unnecessary.

That would be for a cast iron or enameled steel tub. Acrylic tubs need to be fully supported on the bottom.

Setting the base in a mortar bed is preferred. Asphalt shingles are used in cheap construction. Some acrylic tubs have a foam pad pre-installed. These pads are also set in mortar if the floor below the pad isn't level. Select the tub and make it like the picture in the instrucciones.

[ghentjr]

Im installing a bathtub in my basement and had a question regarding leveling the tub. The floor where i am going to install it isnt level (probably off by 1/4-1/2" from wall to front). Would you guys simply level with plastic shims, or would you level the floor first with a floor leveling product? Since i am going to tile the floor, im thinking that leveling the floor would make more sense, but i wanted to run it past you guys first. If you would level the floor, what product would you use? Im getting mixed information with all my searches. Any information or links would be greatly appreciated. Thanks.

Are you excavating the floor for the trap? Is the tub elevated so it drains? Did you apply for a permit?

[Scottpat]

A common and fairly inexpensive way to level and support a tub is to use pre-mixed drywall compound in the box. I see it all the time in my area and also when I lived down in MS. They take the mix out of the box in the plastic bag. They then place it on the floor where the tub will sit. They puncture the bags in a few areas and set the tub on top and level it out. I think most use around 4-5 bags of mix. After a week or so the mix is hard and provides the support needed.

I have also seen bags filled with urathine foam placed under the tub. Seems that both methods work fine. The garden tub in my home is supported with bags of drywall compound.

[Marc]

A common and fairly inexpensive way to level and support a tub is to use pre-mixed drywall compound in the box. I see it all the time in my area and also when I lived down in MS. They take the mix out of the box in the plastic bag. They then place it on the floor where the tub will sit. They puncture the bags in a few areas and set the tub on top and level it out. I think most use around 4-5 bags of mix. After a week or so the mix is hard and provides the support needed.

This one got me laughing, but yes, I can see how it would work pretty good. 'Jobsite ingenuity'. You meant this for an acrylic tub, right?

Marc

[blazenut]

Yes the trap is under the slab already. I was leaning toward the bed of mortar under the acrylic tub myself as well. Thanks for the info.

[John Kogel]

Right, most new tubs would be acrylic and they don't perform well without the support. Lay the moist mortar down in garbage bags or use Scott's trick (maybe not so good, see below).

It is not surprising that when we see them installed wrong, the drain is leaking from the flexing of the floor. This tub was in a newer $600G home. The attached shower was leaking at the drain.

This one has some plywood reinforcement. The skirt is still the only part of the shell that rests on the floor. The trap is under the bit of insulation there.

Click to Enlarge

36.08 KB

[Rocon]

A common and fairly inexpensive way to level and support a tub is to use pre-mixed drywall compound in the box. I see it all the time in my area and also when I lived down in MS.

I have also seen bags filled with urathine foam placed under the tub. Seems that both methods work fine.

Scott,

My concern on this technique is twofold:

1 - If water ever gets into the area the gypsum compound will erode, or if it is under load it will compress due to the moisture

2 - I have a 5 gallon bucket of Compound in my garage that I left to dry out about 2 months ago, here is a picture of it.

Click to Enlarge

37.07 KB

As you can see, it has at least 1/2â€

[Scottpat]

A common and fairly inexpensive way to level and support a tub is to use pre-mixed drywall compound in the box. I see it all the time in my area and also when I lived down in MS.

I have also seen bags filled with urathine foam placed under the tub. Seems that both methods work fine.

Scott,

My concern on this technique is twofold:

1 - If water ever gets into the area the gypsum compound will erode, or if it is under load it will compress due to the moisture

2 - I have a 5 gallon bucket of Compound in my garage that I left to dry out about 2 months ago, here is a picture of it.

Click to Enlarge

37.07 KB

As you can see, it has at least 1/2â€

[Marc]

Mortar. Scroll down to step 4.

Marc

[kurt]

OK, hillybilly boys.......how 'bout expanding polyurethane foam out of the can?

Another unique application for Great Stuff.....................

Personally, I'd pour self leveling cement over the whole floor; it isn't hard, it gives you a great base for tile, and then we're not dinking around with the TIJ version of hillbillies on parade.

If you just ain't gonna do it, I'd shim the tub if it's cast iron...........please say it's cast iron. I'd no more put an acrylic tub in any home I owned than I'd shoot my foot off cleaning my gun.

[gtblum]

Seems like I remember either someone telling me, I read, saw, whatever, about just using a bed of good old regulation sand for this. Anyone else heard of that?

[John Kogel]

I'd no more put an acrylic tub in any home I owned than I'd shoot my foot off cleaning my gun.

You wouldn't go with a one piece tub and shower unit? Now who's the hillbilly? []

BTW, Kurt. I see you let the chickens out this afternoon. I snapped a picture.

Click to Enlarge

54.26 KB

[Erby]

"Don't care what the manufacturer's installation instructions say. Why dang, I been a doing it that way for 20 years. Ain't never had no problem."

Sound familiar? We hear it often enough from framers, plumbers, electricians, etc. Now y'all are advocating it instead of criticizing it.

Don't seem to make sense to me.

-

[Tom Raymond]

And, as we always tell our clients, RTFM!

Warehouse fan Richard?

[ghentjr]

OK, hillybilly boys.......how 'bout expanding polyurethane foam out of the can?

Another unique application for Great Stuff.....................

Actually, that works. But if you don't have the tub full of water or some other heavy weight the tub will get lifted by the foam. Great Stuff. I learned the hard way.

[ghentjr]

OK, hillybilly boys.......how 'bout expanding polyurethane foam out of the can?

Another unique application for Great Stuff.....................

Actually, that works. But if you don't have the tub full of water or some other heavy weight the tub will get lifted by the foam. Great Stuff. I learned the hard way.

[Bain]

OK, hillybilly boys.......how 'bout expanding polyurethane foam out of the can?

Another unique application for Great Stuff.....................

Actually, that works. But if you don't have the tub full of water or some other heavy weight the tub will get lifted by the foam. Great Stuff. I learned the hard way.

I learned the same lesson. When I was a contractor, we installed a steel door in a post office that had 8" x 16" block walls. One of my guys shot Great Stuff into the cavities between the door frame and the block, and the frame, believe it or not, buckled inward. I wasn't there when it happened, but saw the aftermath. It's hard to believe that foam has so much expansive strength, but I now know it does.

[kurt]

I've seen a few houses with every window completely squashed from foam, and I remember the first door I foamed (about 25 years ago) get smashed so tight we had to sledgehammer it open to tear it out.

My own recent hillbilly shot with foam was securing my basement office cabinets in place. My 90 year old solid masonry bungalow doesn't have a square shot in it anywhere, but I don't care; I know how to make it look square.

I placed and shimmed all the cabinets so they were PLS, then I shot foam around the backs, sides, and in under the toe kicks. I let it all set up, trimmed the excess, wood trimmed the areas where the cabinets adjoined the walls and floor, and that's that. Those suckers are tight, and they've remained PLS for about 10 years. Heck of a lot easier than trying to install them conventionally, and I pity the person that tears it all out someday.