What drainage is needed for egress window wells in Calgary?

Proper drainage in egress window wells is absolutely critical in Calgary — without it, spring snowmelt and summer storms will flood the well, push water through the window, and cause catastrophic damage to your finished basement. Calgary's unique combination of deep frost, bentonite clay soils, chinook-driven rapid melts, and position in Canada's hail belt makes window well drainage a non-negotiable component of any egress installation.

The foundation of good window well drainage starts at the bottom of the well. A minimum of 12 inches of clean, washed gravel (3/4-inch clear stone) should fill the base of the well, extending down to connect with your home's weeping tile system. This gravel bed serves as a reservoir that captures water entering the well and channels it to the weeping tiles, which carry it to your sump pit for pumping. If your home has original clay weeping tiles — common in Calgary's 1960s-1980s suburban stock in neighbourhoods like Brentwood, Dalhousie, or Woodbine — they may be clogged or collapsed after 40-60 years and unable to handle the additional water from a new window well. Having your weeping tiles scoped with a camera before installing egress windows can prevent an expensive surprise.

The well walls themselves should be corrugated galvanized steel or high-density polyethylene well liners, secured to the foundation wall with masonry anchors. The well must extend at least 6 inches above finished grade to prevent surface water from flowing in during heavy rains or rapid snowmelt. Calgary receives the majority of its precipitation as snow, and when chinook winds trigger rapid melting over still-frozen ground in March and April, enormous volumes of surface water flow across landscapes — if your well rim sits at grade level, that water pours straight in.

A window well cover is essential in Calgary, though it must be designed for emergency removal from inside. Clear polycarbonate covers keep snow, rain, leaves, and debris out of the well while allowing natural light into the basement. Look for covers rated for Calgary's snow loads — cheap plastic covers crack under heavy wet spring snow. The cover should be hinged or easily removable from inside the well to maintain the egress function. Budget approximately $100 to $300 per cover depending on size and quality.

Backfill around the well should use granular material (gravel or sand), not the excavated clay soil. Calgary's bentonite clay holds water like a sponge, and backfilling with clay creates a bowl that collects water and directs it against your foundation. Lot grading around the well area should slope away from the foundation at a minimum 2% grade for at least 2 metres to direct surface water away. This grading must be maintained — Calgary's freeze-thaw cycles and settling can flatten your grade within a few years if not monitored. Browse basement renovation contractors through the Calgary Construction Network directory to find professionals who understand Calgary's specific drainage challenges.