Cross Section of a Retaining Wall
A retaining wall’s solidity is determined by the strength and stability of its base. Using a 4ft tall cinder block retaining wall as an example, a compacted base of around 4 to 6 inches will be required for maximum stability, as well as 1 inch of leveling sand. A trench deep enough to accomodate the aforementioned materials, as well as half the height of the cinder blocks used. Against a backfill of crushed rock, step each succeeding course back in by ¾ of an inch. The backfill should stop 6 inches from the top of the wall, whereupon you should use a topping of native soil to help prevent water getting into the trench. Cinder blocks should be reinforced with pins, and the cap block – the block placed on the top of the wall – should be secured with a concrete adhesive.