Drainage Solutions
in Walnut Grove, BC

Walnut Grove is one of the Township of Langley's largest and most established residential communities, developed primarily in the late 1980s and 1990s. The neighbourhood sits on the flat benchland between the Fort Langley bluffs and the Nicomekl River, with clay-loam soils that drain slowly. The housing here is predominantly single-family, with crawlspace foundations that are now 25 to 40 years old — old enough that original vapour control and insulation have degraded significantly in many cases.

Drainage problems in crawlspaces have two distinct origins: water that arrives from outside (surface runoff, failed exterior drainage, high water table) and water that condenses from the air inside the crawlspace onto cooler surfaces. The solutions for each are different, and correctly diagnosing which problem you have — or which combination — is the critical first step. Applying interior drainage solutions to an exterior water problem provides partial relief at best; addressing the exterior source is far more effective and usually less disruptive.

Interior drainage systems — perimeter drain tile installed inside the crawlspace along the base of the stem wall — are the right solution when exterior work is impractical (due to finished landscaping, hardscaping, or very tight site conditions) or when the primary issue is groundwater rising from below rather than surface water entering through the wall. Interior drain tile channels water to a sump pit where a pump removes it. This approach does not stop water from entering the foundation, but it manages it effectively once it does.