Attic Air Sealing Before the Insulation Goes In
Air sealing is the first thing Abraham does in an attic. He closes the gaps around everything that comes up through the attic floor, so damp house air stays out of the attic in winter and hot air stays out of the house in summer.
4.9 stars from 136 Google reviewsFree estimate
- About a 10 to 15 minute visit
- Your bid, usually within 24 hours
- Abraham calls or texts back within one business day.
Estimates are free within a half-hour drive of Des Moines.
- Owner on site for every job
- Same crew for 16 years, no subcontractors
- Over 2,000 homes since 2008
- Insured up to $2 million
Insulation slows heat. Air goes around it.
Insulation is good at slowing heat, but air still moves through the gaps underneath it and, with fiberglass, through the insulation itself. That's why Abraham seals the attic floor before any insulation goes in. Piling more insulation on top of open leaks leaves the leaks working.
Free estimate
- About a 10 to 15 minute visit
- Your bid, usually within 24 hours
- Abraham calls or texts back within one business day.
Estimates are free within a half-hour drive of Des Moines.
Soil pipe, flue pipe, wall tops, chaseways: where attic air leaks
Abraham seals around anything that comes up through the attic floor. The ones he goes after:
- The soil pipe, the main plumbing stack that runs up through the attic and out the roof
- The flue pipe from the furnace or water heater
- The joints and seams along the tops of the walls
- Bulkheads, the boxed-in sections of ceiling over kitchen cabinets and similar spots
- Chaseways over the basement stairs in ranch houses
- Chaseways left from an old furnace route in story-and-a-half houses
Leaks under the insulation cause attic condensation
Warm house air carries moisture. When it leaks up into a cold attic in winter, that moisture can condense on the roof deck, the framing and the insulation. Condensation from these leaks is a common problem Abraham finds, and wet or moldy insulation is one of the reasons he ends up removing it.
In summer the same gaps work in reverse, letting hot attic air down into the rooms below, which is part of why upstairs bedrooms get so hot in July. Sealing the attic floor deals with both seasons.
Ventilation belongs to the same work. Abraham installs baffles at the eaves and treats the soffit vents and attic ventilation as part of his air-infiltration work, since poor ventilation is one of the problems he sees most.
Get the attic floor sealed before the insulation goes in
If you're planning attic insulation, the sealing is part of the job. Abraham will point out the leaks he finds when he looks at your attic.
Frost on the nails, dark streaks in the insulation: signs of attic air leaks
You can sometimes spot the evidence from the attic hatch:
- Frost on the roofing nails or the underside of the roof deck in cold weather
- Damp, stained or matted insulation
- Dark streaks in the insulation where air has been filtering through it
- Mold on the roof deck or rafters
- Ice building up along the eaves in winter
- Upstairs rooms that run hot in summer even with the AC on
Attic air sealing, answered
Is it worth air sealing an attic?
Yes. Insulation laid over open leaks still lets house air into the attic, and that air brings moisture that can turn into condensation. Abraham seals first so the insulation can do its job.
Why do ranch and story-and-a-half houses get extra attention?
Chaseways, which are hollow framed channels running up through the house. Ranch houses can have one over the basement stairs, and story-and-a-half houses can have one left from an old furnace route. Both are open paths from the house straight into the attic, and Abraham looks for them specifically.
Does air sealing help in the summer too?
Yes. The same gaps that let humid air escape into the attic in winter let hot attic air into the house in summer.
Is air sealing a separate job from attic insulation?
On an attic job it's the first step of the same job. Abraham seals the attic floor, puts in baffles at the eaves, then blows in the insulation over the sealed floor.
Can an attic be air sealed if it already has insulation?
Yes, though sometimes the old layer needs to come out first. When it's in the way of sealing properly underneath, Abraham vacuums it out, seals the bare attic floor, then reinsulates.
Get a free estimate
Tell us about the house and what's bothering you. Abraham calls or texts back within one business day.
Estimates are free within a half-hour drive of Des Moines.
How we handle your information: privacy policy.