Gravity vs Cantilever Retaining Walls

Almost every retaining wall is one of two types.

Gravity (mass) walls

These resist the soil with sheer weight: segmental block, stacked stone, boulders, mass concrete, timber. Simple, often DIY, no rebar design. The catch is the base: to stay stable they need width, typically 0.5-0.7 × height, and that footprint grows fast with height. Our solver finds the minimum base width for a gravity wall and tells you when it's no longer practical.

Cantilever walls

A reinforced-concrete (or reinforced SRW) wall shaped like an upside-down T or L. The weight of the backfill sitting on the heel does the stabilizing work, so the wall can be much taller with a slim stem. The trade-off: rebar design, formwork, a real footing, and an engineer.

Choosing

• Up to ~4 ft, good soil: gravity wall wins on cost and simplicity.
• Over 4 ft, tight space, or a surcharge: cantilever (or reinforced SRW) wins.

The calculator designs the gravity case directly and flags when you've crossed into engineered-cantilever territory.