Uneven Tub Bottom

[IrishGuy256]

I’m installing a Koehler Devonshire 5’ tub in a remodel. I noticed today that the bottom of the tub does not sit level and rocks back and forth side to side on the floor. On the bottom of the tub, the middle vertical “leg” is not level or flush with the longer vertical legs on either side (see pic). Is that normal? Can I sand it down slightly to make them all flush? Also, the tub comes with plywood attached to front apron and tub. Does this piece stay on? (See pic) Thanks for the help.

 

[Jadnashua]

With my limited experience with Kohler, I'm not surprised that the bottom of the tub is not totally flat. But, giving them credit, it could be your subfloor is not perfectly flat. Often, to overcome that sort of thing, people use some deck mud (a 4:1 sand:cement) mix, laid down in piles, then set the tub on it to make it perfectly level (at the top), and have the bottom more fully supported along more of its surface. A deck mud mix is quite dry, more like damp beach sand. If you go that route, put some plastic down on the subflooring to help prevent it wicking the water away before it gets incorporated into the cement when it cures.

Don't know on that piece of ply, but it may be useful to leave it there so there's more support for the front skirt so it can't be pushed in. The instructions should say something about it, and if not, a call to their tech support may be in order.

 

[Sponsor]

 

[Dj2]

The "plywood" in the picture is really OSB, and I'm pretty sure it's for packing and shipping purposes.

OSB turns into sponge around water.
We use is for roof decks, but then wrap and protect it with felt.

 

[Cacher_Chick]

Have you read the installer instructions? Kohler composite tubs (and most other brands) should be installed in a mortar bed. The mortar should support the tub, not the feet.

 

[Atomic1]

Here's another vote that the tub should be placed on mortar (unless the directions say otherwise). I used a typical mortar mix, piled up on top of plastic. Then mushed the tub down onto the pile in one shot without re-lifting. Trick is to dry fit it first to get your shims in the right position....you dont want to shim it up off of the unhardened mortar pile. Can tell a good tub setting job when the base feels solid as a rock once its cured, and, obviously, that the tub is pitched correctly without getting side dribble.