Seal first, then add depth
Attic Air Sealing & Insulation in Durham, NC
A cooler upstairs in July and a lower bill, starting with the leaks most attics hide under old insulation.
- Free on-site look at the attic and crawl space
- Written quote with foam type, thickness and R-value by area
- Moisture, wood and vent problems flagged before we cover anything
The Attic Decides How Hot the Upstairs Gets
Attic Air Sealing & Insulation is the most cost-effective comfort upgrade in many Durham homes. On a summer afternoon, with the average July high near 91F at the airport, the attic over your ceiling can get far hotter than the air outside. Every gap in the ceiling plane, around light fixtures, plumbing stacks, chimney chases, wall top plates and the attic hatch, lets cooled air escape upward and pulls hot, humid air into the house somewhere else.
Why sealing comes before insulation
Loose-fill insulation slows heat but does little to stop air. If we blow a foot of cellulose over open bypasses, the air keeps moving right through it. So the first part of an attic job is pulling back insulation where needed and sealing those gaps with foam, caulk and rigid board. Then we add insulation over the top.
How much insulation
North Carolina's 2018 Energy Conservation Code calls for R-38 in ceilings for new work in Climate Zone 4A, which includes Durham County. ENERGY STAR's retrofit guidance is higher: R-60 for an attic with no insulation, and R-49 added where 3 to 4 inches are already there. Most attics we see in the Triangle hold well under R-38, often settled fiberglass or old cellulose a few inches deep. We measure what you have and write the target depth and R-value on the quote.
Ducts and air handlers in the attic
Many Triangle houses built from the 1970s onward put the air handler and ductwork in the attic. Leaky ducts and poorly insulated ones lose cooling to the hottest place in the house. In some homes the better fix is to spray foam on the underside of the roof deck so the ducts sit inside the conditioned space. In others, sealing duct joints and burying ducts under deep loose fill works. We will explain the trade-offs.
Ventilation stays open
In a vented attic, soffit vents need a clear path. We install baffles at the eaves before adding insulation so the vents keep working. We also check that bath fans vent outside, not into the attic, since that moist air causes problems in winter. If you are planning roof work, tell us; sometimes it makes sense to time the two together. Get a free estimate
What an Attic Job Includes
Sealing, insulation and the details that keep it working.
Bypass sealing
Foam, caulk and board over gaps at plumbing, wiring, chases, top plates and light fixtures.
Hatch and pull-down stair covers
Weatherstripping plus an insulated cover so the opening is not the weakest spot.
Baffles at the eaves
Keep soffit vents open before insulation goes in.
Blown-in to depth
Cellulose or fiberglass to the R-value on your quote, with depth markers you can check.
Roof deck foam option
For attics with ductwork or a planned conversion, foam under the roof deck instead of on the floor.
Typical Attic Air Sealing & Insulation Costs
| Job | Published range (source) |
|---|---|
| Average attic insulation job | $1,000 to $2,700, around $1,800 on average (HomeGuide) |
| Attic air sealing | $350 to $3,000 (HomeGuide) |
| Blown-in for an attic | $0.90 to $2.40 per sq ft (HomeGuide attic guide) |
| Spray foam on the attic floor | $1,100 to $6,800 (HomeGuide) |
| Spray foam under the roof deck | $1,500 to $9,000 (HomeGuide) |
| Attic spray foam, existing home | $2,500 to $12,000 (Fixr) |
| Removing old insulation | $1 to $2 per sq ft (HomeGuide) |
Sources: HomeGuide attic insulation guide (January 2026) and Fixr spray foam guide (2025); these are national ranges. How much sealing is needed, target depth, access and any removal shape the total, and the figure on our written estimate is the one you pay.
How We Do an Attic
1. Measure
Depth of existing insulation, condition, bypasses, ducts and ventilation.
2. Quote
Air sealing and insulation priced as separate lines, with the target R-value.
3. Seal
Bypasses closed, hatch insulated, baffles installed.
4. Insulate
Loose fill blown evenly to depth, or foam applied to the roof deck if that is the plan.
5. Show you
Photos and depth markers so you know what is up there.
Why Choose Us for Attic Air Sealing & Insulation
Sealing is its own line
You see what the air sealing costs and what it covers.
Depth you can verify
Markers stay in the attic so anyone can check the depth.
Ducts considered
We look at the ductwork and air handler, not just the insulation.
Attic Air Sealing & Insulation Questions
What R-value insulation for an attic in NC?
The 2018 North Carolina Energy Conservation Code calls for R-38 in ceilings in Climate Zone 4A. ENERGY STAR recommends R-60 for an uninsulated attic and R-49 added over 3 to 4 inches of existing insulation.
Should I remove old insulation before adding more?
Only if it is wet, moldy, contaminated by rodents or in the way of air sealing. Dry, clean insulation can usually stay, with new insulation blown over the top after the bypasses are sealed.
Will attic insulation help my upstairs stay cool?
Sealing and insulating the attic floor cuts heat coming down through the ceiling and stops cooled air leaking up. If the upstairs includes a bonus room with kneewalls, those walls usually need attention too.
Does Duke Energy pay for attic insulation?
Duke Energy lists an instant rebate for raising single-family attic insulation to at least R-38, applied by a Duke-approved contractor after a free Home Energy Check. Check with Duke that your account qualifies.
Attic Air Sealing & Insulation Service Areas
- Spray Foam Insulation in Durham, NC
- Spray Foam Insulation in Chapel Hill, NC
- Spray Foam Insulation in Carrboro, NC
- Spray Foam Insulation in Hillsborough, NC
- Spray Foam Insulation in Morrisville, NC
- Spray Foam Insulation in Cary, NC
- Spray Foam Insulation in Apex, NC
- Spray Foam Insulation in Raleigh, NC
- Spray Foam Insulation in Wake Forest, NC
- Spray Foam Insulation in Creedmoor, NC
- Spray Foam Insulation in Butner, NC
- Spray Foam Insulation in Mebane, NC
- Spray Foam Insulation in Pittsboro, NC
- Spray Foam Insulation in Roxboro, NC
- Spray Foam Insulation in Oxford, NC
Get an Attic Air Sealing & Insulation Estimate
Send a photo from your attic hatch and we will set up a visit.