Is it safe to store hay at ground level on large sheets of rubber? Looking to get away from stacking on pallet?

I have access to large rubber sheet (20' X 60') and would like to begin storing my hay on them; basically lay the rubber sheets on the floor and then stack the hay on it. I thought this would prevent the moisture from coming up from the ground and molding my hay and remove the issues with walking on pallets. Has anyone ever stored hay on sheets of rubber before?