Installing 3-wall Alcove tub with apron

[91Aggie]

I searched this forum and found some similar questions, but want to make double and triple sure on this before I try to DIY this thing.

I've got a 42x60 Kohler Acrylic Garden alcove tub. It's got a non-removable apron on it.

I'm at the point where I need to try and install it.

I've heard all sorts of advice from many people about what needs to go under it (the reason I'm putting this one in is the builder didn't put anything under the original one and the bottom eventually cracked after 10 years of use).


So, it seems that the best thing to do is put mortar under the tub/basin part.

My problem/concern is that I can put lay some down between the 4 "feet" that shipped with the tub, but once I set the tub down, I won't have access underneath it to make sure that the mortar doesn't get underneath the feet.

Other question is, how much mortar do I put down... make it higher than the current space between the bottom of the base and the 4 feet so that it "mush" down into the mortar.

I want the basin supported so we don't have the same problem in 10 years, but I'm perplexed as to how a "pro" would do this.

Thanks in Advance.

[jadnashua]

A sand mix is more like wet beach sand, so it doesn't flow, but will still smush some (depends on the proportion of sand to cement - you can buy it premixed - just add water - at about a 3:1 ratio; more sand means it won't smush as easily (5:1 is often used for making a shower pan slope), but the higher cement means it is a little stickier). You can put some piles of it in areas that won't interfer with the feet and smush it down. You want enough to cover a good portion of the base, but you don't need to cover it perfectly in its entirety. Put some tar paper or plastic down on the plywood, and you can cover it with some, too. The layer on the bottom keeps it from drying out to fast by the ply sucking the moisture out; the layer on the top prevents the tub from sticking (although the stuff isn't all that sticky). YOu have two goals, support the bottom and make it perfectly level.

[91Aggie]

Thanks for the reply.

The foundation is concrete, so it's not going on plywood.

[Terry]

When I place mortar under a tub, I place piles that have enough room to squish out.

If you try for a solid and level mortar job, it rarely works.

[dcelite]

Put 2 x 4 ledgers on the walls for the lip of the tub to rest on. If you make your ledgers level, then when you squish the tub down in the mortar, until it rests on the ledgers, it will be level. Set the ledger so the tub will end up about 3/4" above the subfloor or whatever height will allow you to cover the edge of the skirt with the finish flooring. This will give you a little room if there's mortar under the feet.