Flagstone: what to use, sand, cement, or gravel? | Devine ...
Mar 19, 2014· Thus it's not too much trouble to just get your gravel foundation pretty close to perfect, then go ahead and screed out one inch of sand for your bricks to rest upon. With flagstone however, the thickness will vary too greatly—you may need half an inch of sand for one stone, but 2 inches for another.