Retaining Wall Reading PA A block retaining wall helps transform the backyard to a level usable space ready for outside activities. Before excavation, the slope of the rear of the yard was steep and overgrown. After excavation, the retaining wall is built, drainage controlled, and backfill is started. The finished grade after the retaining wall is finished provides extra space and a low maintenance property line. Finishjed side of the retaining wall from below with grass seed planted.