I remodeled the bathroom last summer and installed a new bath tub. It is an acrylic tub and the directions said that as an option the tube could be placed on a bed of morter. My father in law said there was no need to do this because these tubes are designed to be used with out it. So we did not use morter. Now the tube squeaks not stop while you are in it. I feel that it may crack and was wondering if there is any way to get concrete under the tub (or anything else) to make the bottom more sturdy and stop the squeaking. It would be impossible to take it out without destroying the walls. I have been told that foam would not work because it gives to much.