Installing a tub over a mortar base..

[Aintlifegrand]

We are finally getting ready to install our bathtub.. Yea!..No more outdoor showers in the winter...Anyway I was reading in the instructions that you can install the tub over a mortar base for strength etc. The tub is a Kohler made of Vickrell... I was wondering if anyone had done this before and if so.. what type of mortar..is it type s or what? How thick should the mortar bed be also.. Thanks for all your help!

Stephanie

[Katey]

I don't know what Vickrell is, but I've installed a bathtub. Basically, you mix up some mortar so that it is thick enough that it doesn't slump. You don't need to pave the whole area under the tub, just make a blob under the area where you'll be standing or sitting the most. Make it a little higher than you need, so when the tub is set down on the wet mortar it will be form-fitting. Cover the blob with a sheet of plastic (to make your life easier if you ever have to take the thing out) and set the tub in place. If the space is heated, a day will be plenty to let the blob dry.

eta: put a piece of plastic under the blob, too, if you don't want to chip it off the flooor later.

[cfabe]

I have also seen folks use great stuff expanding foam and coat the whole area under the tub, then set the tub in while it's still wet.

[Aintlifegrand]

Wanted to add the subfloor is 3/4 plywood on 2x10 joist 16" on center...in case that mattered.

[rancher1913]

usually the motar bed is only needed if a very obeese person uses the tub on a regular basis, the motar simply supports the bottom of the tub and keeps it from cracking. the best way I found to do it is a combo of the two answers above--use foam as a dam around the inner base and then mix up grout and pour it in the void. avoid the drain area so you can acess the plumbing in the future.