One of the great things about segmental retaining walls (SRWs), is the fact that the installer does not need to excavate to frost depth and/or pour a concrete footing below the structures. This helps reduce cost and speed up the installation of the systems. SRWs are flexible in nature, and only require minimal burial below grade. So, how much block do I need to bury on my first course? The industry recommends that your first course be buried a minimum of 1ft (2.5cm) for every foot (.3m) in wall height, or 6ft (15cm) (whichever is greater) if the ground in front of your wall is flat.
For unique applications where a slope is running away from the face of the wall (pictured below), the industry has a different recommendation of 5ft (1.5m). This means that though you have a slope downward, the soil against the block is still 5ft (1.5cm) deep. the burial outlined in both situations helps reduce the likelihood of erosion at the front face of the wall.