Around the house
Drainage and gutters
Most ‘mystery moisture’ in BC houses starts at the perimeter: a downspout, a reverse slope, or a window well acting as a rain barrel.
Gravity is on your side if you let it work. Rain that hits the roof should leave the property without lingering against the foundation. In the Lower Mainland that is a lot of water over a lot of weeks. Small grading mistakes add up.
The short list that actually moves water
- Gutters sized and pitched so they do not overflow at corners
- Downspouts that discharge several metres from the wall, not into a splash block at the footing
- Soil that falls away from the house — even a few centimetres over the first metre helps
- Window wells with drains that are not packed with leaves
- Driveways and patios that do not pitch toward a basement wall
Gutters in moss country
Needles and moss turn gutters into planters. Clean them before the fall rains, not after the first overflow stain appears on the fascia. Guards help on some roofs and clog on others (especially under cedars). If you install guards, you still need a way to inspect the outlet.
When the lot is fighting you
Hillside lots in North Vancouver, Coquitlam, and similar terrain shed water toward the house whether you like it or not. That is swale, catch basin, and sometimes professional drainage territory. Interior waterproofing will not fix a river against the uphill wall.