I feel your pain. I had to come up with
a solution to the same problem last december.
Here is what I did.
1) made a rectangular frame (equal to 'mortar contact area' in diagram) and mixed up some regular builders grade mortar- 2 fifty pound bags.
2) I poured the mortar into the frame, and allowed it to set-up for a couple of hours.
3) pulled wooden frame out and carried the tub in (already had the support risers in place ---> IMPORTANT)
4) set the tub in place and walked in the tub to
squish the tub down into the mortar. The support risers will now be at the correct height if you followed those steps correctly.
5) Hooked up the drain and filled the tub with
water to seat the tub and test for leaks.
The tub, even though sitting on a plywood subfloor, feels like it is sitting on a concrete
you can e-mail me with questions if you need to
: : I'm putting a Jacuzzi in an alcove. They say it should supported underneath with a bed of mortar or
: : plaster covered with 2 mil poly. I checked old messages here & they don't quite lay out the details
: : as much as I'd like... 1) Exactly what kind of mortar and plaster? 2) Which is preferable, and why?
: I have used mortar that comes in the 60 or 80 pound bags from the hardware store, and fixall.
: : 3) Is plaster water-proof, or will I have a big mess if there's a leak?
: If you have a big leak, more than the support under the tub will have problems. The ceiling will be the first to go.
: 4) Can the material be removed
: : easily later?
: Not really. A hammer and chisel will help.
: 5) IMPORTANT - Do I just mound it up underneath & plop the tub on top? Won't it
: : squish/flow out from underneath?
: I mound up the material in lumps beneath the tub, which allows room to spread. If too much material is beneath the tub, you will not be able to push the tub down.
: : This is a sensitive issue for us since our current tub cracked in the middle from improper support/
: : installation by the builder (BTW we also got stuck with polybutylene pipes that split open, and didn't
: : hear about the settlement til too late...)
: : One other question - should I put some kind of insulation between the tub & alcove walls to cut
: : down on noise? Thanks for the great site by the way!!!
: Thanks, Insulating is good, however, the tub makers like to have some venilation for the motor.