Generally, walls under 3-4 feet (including the buried portion) might not require an engineer, but always check local building codes. Taller walls often need professional design and permits.

Proper drainage (e.g., gravel backfill, perforated pipe) relieves hydrostatic pressure, which is water buildup behind the wall. This pressure is a primary cause of wall failure.

It depends on your location and the wall’s height and design. Many jurisdictions require permits for walls over a certain height (e.g., 3 or 4 feet).

Batter refers to the slight backward lean or setback of the wall into the hillside. This improves the wall’s stability against overturning.

A common rule is to bury at least 10% of the wall’s total height, plus more in frost-prone areas (below the frost line). A stable, compacted base is crucial.

Common materials include concrete blocks (segmental retaining wall units), poured concrete, treated landscape timbers, natural stone, and gabions.

Geogrid is a soil reinforcement material laid horizontally within the backfill and connected to the wall. It’s often required for taller walls or those supporting heavy loads to increase stability.

Typically, you’ll need a layer of gravel at least 12 inches deep directly behind the wall, extending from the base to near the top. This calculator provides an estimate for that volume.

Yes, absolutely. A well-compacted base prevents settling. Compact backfill in layers (lifts) to ensure good stability and drainage.

Poor drainage, inadequate base preparation, not accounting for soil pressure, building too high without engineering, and not checking local codes are common pitfalls.