Hi everyone, first timer here. I have built slab for a large shed. The shed will be wood frame and divided into two rooms, one a store for a ride on mower, and the second room to be plaster boarded and made into a clean area store room. The slab consists of 7 inch of MOT with 4inch concrete slab. I have NOT put polyeuro sheet under the concrete layer, whoops. Does this matter? i know its best practice, but too late now! Thanks for helping.[/b] B