Wooded Timber Retaining Wall Downingtown PA The new timber retaining wall holds back the wooded hill to eliminate erosion directed toward the house. It compliments the surrounding environment while creating a beautiful garden space. The previous retaining wall provided only small usable space and does not properly control erosion. Excavating to provide more usable space and a foundation for the new retaining wall. Building the timber retaining wall showing the back structure that keeps the wall intact and long lasting.