Drainage Solutions
in Coquitlam, BC

Coquitlam's topography is dramatically varied — from the near-flat Como Lake area and the Burquitlam lowlands to the steep slopes of Burke Mountain, where residential development has pushed into terrain that was forestland a generation ago. This range means crawlspace conditions are highly site-specific. Burke Mountain homes on new lots sometimes deal with cut-and-fill grading that has disrupted natural drainage patterns, directing water toward foundation walls in ways that were not anticipated during construction. Lower Coquitlam properties in areas like Burquitlam and Maillardville deal with the older housing stock that characterizes the lower Fraser Valley — vented crawlspaces, original fibreglass insulation, and moisture damage that has accumulated over decades.

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.