How thick should your epoxy flooring coating be? Economics play a major role in determining how much coating to apply. One U.S. gallon contains 231 cubic inches. That's only 1.6 cubic square feet of surface at one inch thick and that's also assuming a solvent-free product. If the epoxy flooring is 25% VOC (i.e. 25% solvent) then dry thickness/coverage will be 25% less. Again, assuming a 1/4 inch thick epoxy flooring coat (250 mils) maximum coverage will still be only 6.4 square feet per gallon. A solvent-free (100% solids) coating applied at 16 mils will cover 100 square feet per gallon (note: the wall paint in your office is probably 2-4 mils with epoxy flooring).