Heat rises, and in an Alberta house it rises straight into a cold attic through every pot light, plumbing stack and attic hatch that isn't sealed. The result is the winter trio homeowners know well: high heating bills, cold rooms below, and ice damming at the eaves as escaping warmth melts the roof snow that then refreezes. The attic is usually the highest-return place to fix a leaky house.
Two ways to insulate an attic
The right approach depends on whether you keep the attic vented:
- Vented attic, foam the flat. Air-seal the ceiling plane with foam at the penetrations and top plates, then build depth with blown-in to reach the R-value cheaply. This is the hybrid "flash-and-batt" idea applied to an attic - the air-seal of foam with the affordability of blown-in.
- Unvented, foam the roof deck. Bring the attic inside the envelope by spraying the underside of the roof deck - typically 5 to 8 inches of closed-cell. Good for attics with mechanicals up there, cathedral ceilings and tricky rooflines.
Hitting R-38 (and what it takes)
Alberta attics target around R-38. In foam terms that's roughly 6 inches of closed-cell or 11 inches of open-cell - a real difference in depth and cost that a good installer will walk you through. Use the calculator to estimate board feet for your square footage and target R.
What it fixes
- The air-seal kills the drafts and cold rooms.
- Reaching real R-value cuts the heating load.
- Sealing the ceiling plane is also the fix for recurring ice dams, because it stops the escaping heat that causes them.
Attic work is where insulation pays back fastest in this climate. Get a free quote and have a vetted installer confirm vented-vs-unvented for your roof.