An attic in Lethbridge faces a problem most Alberta attics don't: relentless wind. As the windiest city in Canada, Lethbridge subjects every roof to constant pressure that drives air through the smallest attic gaps and lifts warm air out of the house. A calm-climate attic might tolerate a few leaks; a Lethbridge attic pays for every one, every windy day - which is most of them.
Why wind changes the attic game
Wind creates pressure differences across the roof that actively pump air through unsealed pot lights, top plates and the attic hatch - far more aggressively than the passive stack effect alone. Insulation that isn't air-sealed simply lets the wind blow through it.
The fix
- Vented attic: air-seal the ceiling plane with foam (this is what beats the wind), then top with blown-in to R-38.
- Unvented / complex rooflines: closed-cell to the roof deck, common in newer areas like Copperwood and Garry Station.
R-38 is about 6" closed-cell or 11" open-cell. Estimate yours, then get a free Lethbridge quote. See attic foam province-wide.