I am working on taking out my back seat and putting in an amp with a false floor. I was wondering if anyone knows of a good spray on insulation, or anything of the sort that I could spray into the cracks between the board and the outside of the car. Hopefully I can kind something that will get hard enough to stand on w/o it squeshing. I don't care how ugly it looks because I will be carpeting over it. Thanks for any help!

build the floor right you wont need anything to fill it in..