Attic Insulation & Air Sealing in Iowa City, IA

Attic insulation and air sealing usually gives Iowa City homeowners the most comfort per dollar. Warm air rises and escapes through every gap in the ceiling: around light fixtures, plumbing vents, chimney chases, wiring holes, the attic hatch and the tops of interior walls. In winter that warm air also melts snow on the roof, which refreezes at the eaves as ice dams.

Seal first

We start by sealing those bypasses from the attic side with foam, caulk and rigid blocking. Larger openings such as chases and dropped soffits get covered and sealed. The hatch gets weatherstripping and insulation. HomeGuide lists air sealing at $350 to $3,000 depending on how much there is to do.

Then bring it to depth

Once the floor is sealed, we add insulation to reach the target. Iowa's adopted energy code calls for R-49 in ceilings for Climate Zone 5. For an existing home, the Department of Energy suggests R-60 in an attic with no insulation, or about R-49 added where 3 to 4 inches are already there. Blown-in cellulose or fiberglass is usually the most economical way to get there, at roughly $0.90 to $2.40 per square foot in HomeGuide's attic guide.

When foam belongs in the attic

Some attics are not simple. Finished attics with kneewalls, cathedral ceilings, and attics with ductwork or a furnace in them may do better with foam on the roofline or in the slopes. That makes the attic part of the conditioned space. It costs more, about $1,500 to $9,000 for the roof deck in HomeGuide's figures, and it is not the right call for every house. We explain the tradeoffs.

Ventilation matters too

A vented attic needs open soffit vents and a clear path for air. We install baffles at the eaves so new insulation does not block them, and we make sure bath fans vent outdoors instead of into the attic. Get a free estimate