Poured Concrete Retaining Walls
Poured concrete retaining walls are the strongest option for holding back earth — stronger than block or timber. They're typically used when wall height exceeds 4 feet or when structural loads (driveways, buildings) sit above the wall. Below 4 feet, segmental block walls are usually more practical and economical.
A poured retaining wall needs a footing that's wider than the wall itself — typically 2× the wall thickness. The wall also needs drainage behind it: a gravel backfill zone with a perforated drain pipe at the base to relieve hydrostatic pressure. Without drainage, water pressure will eventually crack or overturn even a well-built wall.
For walls over 4 feet, most jurisdictions require engineered drawings, a building permit, and inspection. The National Concrete Masonry Association publishes design standards for both poured and block retaining walls.