need help

hi, this is my first post here as i was directed here from john bridge forums.

here is my question. i am nearing the end of construction on my new home and my plumbers just put my master bath tub in since we tiled the deck and needed to wait till after that was done.

it seems that my deck is a little high. there is about 2" of space between the bottom of my tub and the concrete slab.

my plumber said that he normally puts expanding foam under tubs like that but usually sees an inch or so of gap.

we are trying to figure out if we will be ok putting foam in this gap even though its about 2" maybe 2 1/4".

if foam is ok, what type.

thanks for any help!!

if its a fiberglass/acrylic "drop in" it probably says in directions not to support the tub by the lip. it will definitely crack and break! its better to be too low than too high with this cause you can always build up. i would pull the tub. lay 2 layers of 3/4" plywood. then more than you need layer of structurelite setting compound (found in h.d.). set the tub, shim under the lip with cardboard, then wiggle the tub down. connect the drain then fill tub with water to hold down overnight. cut out the cardboard then caulk the lip/tile joint with phenoseal.