Attic Spray Foam Insulation Alberta

Attic Spray Foam Insulation Alberta: Two Ways To Do It

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 Spray Foam Insulation Alberta: Common Questions

How much spray foam does it take to reach R-38 in an attic? Roughly six inches of closed-cell, or about eleven inches of open-cell. That depth difference is the whole reason the two foams are priced differently for the same R-value, and it is worth understanding before you compare quotes. Estimate your board feet for your square footage and target R.

Should the attic stay vented, or should I foam the roof deck? It depends on what is up there. If the attic is empty and the ceiling plane is accessible, air-seal the flat with foam and build depth with blown-in - you get the air-seal where it matters and the R-value cheaply. If there are mechanicals in the attic, or it is a cathedral ceiling or an awkward roofline, bringing the space inside the envelope by foaming the underside of the roof deck is usually the better answer.

Will spray foam stop ice dams? It addresses the cause rather than the symptom. Ice dams form when heat escaping through the ceiling melts roof snow that then refreezes at the cold eaves. Sealing the ceiling plane stops that heat getting into the attic in the first place. Adding insulation without sealing the air leaks treats the symptom and usually disappoints.

Why is the attic the first place to look? Because heat rises, and in most Alberta houses it leaves through every pot light, plumbing stack and attic hatch that was never sealed. That makes the ceiling plane the highest-return surface in the building - the same money spent there generally does more than it does anywhere else.

Can blown-in insulation go over spray foam? Yes, and on a vented attic that is often the sensible build: foam at the penetrations and top plates to do the air-sealing, then blown-in on top to reach the target depth. The foam does the job blown-in cannot, and the blown-in does the depth more cheaply than foam would.

How is attic spray foam priced? By the board foot - one square foot at one inch thick - so a 1,000 square foot attic at six inches is 6,000 board feet, not 1,000 of anything. Area, target R-value, which foam, and access are the drivers. Nobody can give you a real number without seeing the attic.

Attic work is where insulation pays back fastest in this climate. Get a free quote and we will confirm vented-vs-unvented for your roof.