French Drain

Category: infrastructure

A subterranean drainage trench system designed to redirect pooling groundwater away from a building foundation.

A French drain consists of a sloped trench containing a perforated PVC line wrapped inside a geotextile fabric layer and surrounded by clean gravel. Hydrostatic pressure forces pooling ground moisture into the gravel bed and down through the perforated line, channeling it safely away from basement walls.

Common Examples

• We excavated a perimeter trench to install a French drain, eliminating the hydrostatic water logging along the crawlspace wall.
• A French drain line must be installed with the drainage perforation holes facing downward into the aggregate gravel base bedding.