Building a Raised Lawn Over Concrete: Drainage Is Critical

Why You Must Break Up the Concrete Base

Laying soil directly on intact concrete creates a bathtub effect—water pools at the bottom, suffocating roots and causing rot. Even 12–14 inches of soil won't fix this.

Proper Construction

1. Remove or fracture the concrete (jackhammer or hire removal) to allow vertical drainage.
2. Use 8+ inches of blended soil: 1 part landscaper's mix (peat, humus) to 1 part sandy loam.
3. Edging: Railroad ties (sleepers) work if untreated (no creosote). Line the inside with landscape fabric to prevent soil contact with any residual chemicals.

Alternative Ideas

Consider a patio with pavers, containers, or a fire feature instead of lawn—less maintenance, better suited to a hard base.

If you proceed with grass, drainage is non-negotiable.