How many Keystone units should be buried?
Typically, 1″ (25mm) is buried for every 8″ (200mm) of wall height with a minimum of 6″ (150mm) below finished grade. In most cases, other than where the grade slopes away from the wall at the base, 3 to 4 units are the maximum to be buried on tall walls. More than that does not create an added benefit. Unit burial is not a function of building below frost depth in cold climate areas like rigid wall systems, but is meant to provide resistance to base exposure from erosion to grade in front of the wall.
