Blown-In Insulation in Asheville, NC

Blown-in insulation is the workhorse of attic upgrades. A machine blows loose cellulose or fiberglass across the attic floor, filling around joists, wiring and odd framing that batts never fit well. On a sealed attic floor in an Asheville home, it is usually the lowest-cost way to reach the depth ENERGY STAR recommends for Zone 4A: R-60 for an attic with nothing in it, or roughly R-49 added on top of 3 to 4 inches.

Cellulose or fiberglass?

Cellulose is made mostly from recycled paper treated for fire and pests. It is denser, resists air movement better, and is the usual choice for dense-pack walls. Fiberglass is lighter, does not absorb water, and needs more depth to reach the same R-value. Fixr lists blown fiberglass at $1.65 to $2.60 and cellulose at $1.75 to $3.80 per square foot. Either works well in an attic when the leaks below it are sealed first.

Why sealing comes first

Loose fill slows heat moving through it, but air can pass through it. If warm air is leaking up around a plumbing stack or chimney, it moves right through the blown-in layer. That is why we seal the attic floor before blowing, and why we pair blown-in with foam at the bypasses. It is also why blown-in is less suited to walls of a crawl space or rim joists, where foam does the job better.

Doing it right

• Baffles at the eaves keep soffit vents open.
• Dams around the hatch keep loose fill from spilling.
• Recessed lights are checked for insulation contact ratings.
• Depth markers are set so you can see the installed depth.
• The installed R-value and depth are written on the invoice.