Our whirlpool tub was installed after framing was complete and apparently they didn't pay attention to the fact that the base of the tub is not supported. If you step into the tub, the bottom is very squishy and you can hear crunchy sounds. Everything has been hooked up and secured so taking the tub out seems impossibly. Our plumber suggested either spraying foam or using sand. I don't get how we can get either thoroughly under the tub. My thought is to slide a sheet of water-resistant sheet rock, or whatever you use in a bathroom. Clearly, I need HELP!