Question
On top of a already built drain-equipped concrete slab, if want put grass on top, what would be the thickness of grass+soil+drainage mat(if needed) above the concrete finish?
Thanks a lot

Answer
Hi Derick;
If you have a retainer to keep the soil from running off, I would think 8 to 10 inches would be enough. If you want shrubs too, you would need deeper soil to allow for the seeper roots, unless you broke up the concrete and removed most of iut where you want the shrubs.

Chartotte