Under the house
Crawl spaces on the wet coast
Many BC houses were built with vented crawl spaces meant to ‘breathe.’ In a humid coastal climate, those vents often pull in wet air and leave the wood sitting in a greenhouse.
A crawl space is a short void under the main floor. In older Lower Mainland and Island homes it is frequently dirt-floored, lightly insulated, and fitted with screened wall vents. The original idea was to flush moisture with outdoor air. That works in dry regions. Here, outdoor air is often wetter than the wood you are trying to protect.
Signs the void is working against you
- Musty smell in closets or along baseboards on the first floor
- Floors that feel bouncy, cold, or slightly out of level
- Visible mold on joists, insulation hanging like wet batting
- Rodent sign, or rusted HVAC in the crawl
- A dryer or bath fan that terminates under the house instead of outdoors
What encapsulation is trying to do
Modern crawl-space work in wet climates usually means: cover the soil with a heavy vapor barrier, seal the wall vents, close air leaks to the living space, and run a dehumidifier or conditioned air so the void stays dry. The liner is not magic by itself — if groundwater is ponding, you still need drainage or a sump.
DIY plastic on the dirt can still help if it is overlapped, weighted, and run up the walls. Cheap thin sheeting that gets shredded by the next inspection trip does little. Leave structural jacking, mold on framing, and electrical in the crawl to people who work under houses for a living.
The dryer-vent trap
A surprising number of BC homes dump dryer exhaust into the crawl or a jumble of crushed foil duct. That is moisture plus lint plus fire load. If drying a load takes two cycles, look at the vent path before you buy a new dryer.