Some manufacturers use pins to align the blocks in their segmental retaining walls. Versa-Lok’s pin system ensures that each course has a 3/4-inch setback, giving the wall face an angle of about 7 degrees away from vertical.
In Lock Load’s retaining wall system, face pieces are attached to separate anchoring components called counterforts.
While construction details vary, all segmental retaining walls require a well-compacted gravel base and good drainage, and geogrid is often used to reinforce the wall assembly. Engineering is usually required for walls taller than 4 feet or in poor soils.
Segmental retaining walls don’t require a concrete footing but do require a solid base of compacted crushed rock.
Some manufacturers recommend adding a layer of coarse sand to make leveling the first course of block easier.
Synthetic geogrid is used when retaining walls are built on soils containing a lot of silt or clay, or when wall heights exceed 4 feet.
The first segmental retaining wall you build likely won’t look like this, but the photo illustrates the design possibilities offered by these versatile systems, including curved walls and planting areas.