im not sure to be honest. i think ive used about 80 sq ft so far and thats 2 layers just about everywhere, and more on the 1/4 panels, and thats from the back wall up too about 3/4 of the floor. im thinking it will take 110sq ft to cover from the back wall to the top of the firewall in 2 layers. and you can either get it at a dealer near you or at Sound Deadening Materials for Noise Reduction from Second Skinhow much did it take to do the whole floor