Understand Retaining Wall Drainage

What happens here

Responding to the homeowner's question about a drainage pipe and French drains, the expert explains that the backfill stone behind a retaining wall serves a similar purpose to a French drain. Its function is to allow any moisture or water that finds its way behind the wall to escape freely, preventing it from accumulating, freezing, expanding, and pushing the wall out. He describes the components of a proper drainage system behind a retaining wall: digging out soil, lining the trench with fabric, filling it with stone, and installing a perforated drain pipe at the base of the first course of the wall, which should be routed to discharge water completely outside the wall.

Goal: Explain the function and proper construction of drainage systems behind retaining walls, including French drains.