The fiberglass mat its self is 2 layers. Then more resin on top. The walls are probably a little over an 1/8 think and the floor close to 1/2" thick.cool two coats, I figured it would take more than that lol , is that even 1/8 inch thick just curious, I still havent done my test to see how it works, but I when i build my tank, I am t hinking of lining it with 1/8 inch pvc sheet and then either using polygem epoxy putty or sanitreds permaflex to seal all of the seams