The attic is where summer heat comes in
Attic Air Sealing & Insulation in Santa Rosa, CA
Seal first, then insulate to the depth the house needs.
- Free on-site estimates
- Itemized written quote: material, thickness or depth, and R-value per area
- Air leaks, wiring and moisture checked before anything gets covered
Why the Attic Comes First
Attic Air Sealing & Insulation is usually the best-value insulation job in a Santa Rosa house. On a 90°F afternoon, and the city averages 28.9 of them a year, a roof bakes the attic well above the outdoor temperature, and that heat pushes down through thin insulation into the rooms below. In winter, warm air leaks up through gaps in the ceiling. Sealing those gaps and adding depth fixes both.
Seal first
Air leaks carry more heat than many people expect. Common leaks in Santa Rosa attics include top plates over interior walls, recessed can lights, the gap around a chimney or flue, plumbing and wiring holes, attic hatches and duct boots. We seal these with foam, caulk or the right fire-rated material before adding insulation, because once they are buried they are hard to reach.
Then insulate to the right depth
ENERGY STAR recommends R-49 for an uninsulated attic in zone 3, or adding R-38 where three to four inches are already in place. OpenEI lists Sonoma County in climate zone 3C. In most attics, blown-in fiberglass or cellulose reaches those levels for less than foam. Foam goes on the roof deck instead when the attic holds ducts or equipment, or when a vaulted section has no attic at all.
Attics after the fires
Many Santa Rosa homes that survived 2017, 2019 or 2020 had smoke or ash pulled into the attic through vents. If insulation smells of smoke or is visibly dirty, removal and replacement is an option; talk with your insurer about coverage. Homes in wildland areas built since 2008 also have stricter rules, including mesh coverings on attic vents, so we keep vents clear and baffled.
Ventilation
A vented attic needs open soffit and ridge or gable vents. We install baffles at the eaves so new insulation does not block airflow.
What This Covers
Attic work, sealed and insulated in the right order:
Air sealing
Top plates, can lights, flues, wiring and plumbing holes, hatches and duct boots sealed before insulating.
Blown-in top-up
Fiberglass or cellulose blown to the target R-value over what is already there, if it is clean.
Baffles and vent clearance
Eave baffles keep soffit vents open so the attic can breathe.
Hatch insulation
An insulated, weatherstripped cover for the attic hatch or pull-down stairs.
Roof-deck foam
Spray foam under the roof deck where ducts or equipment sit in the attic.
Old insulation removal
Smoke-tainted, wet or rodent-soiled insulation vacuumed out before new goes in.
Published Attic Insulation & Air Sealing Costs
| Job | Range and source |
|---|---|
| Attic insulation, average job | $1,000 to $2,700, about $1,800 average (HomeGuide) |
| Air sealing | $350 to $3,000 (HomeGuide) |
| Blown-in, 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 on the roof deck | $1,500 to $9,000 (HomeGuide) |
| Spray foam, attic (existing home) | $2,500 to $12,000 (Fixr) |
| Old insulation removal | $1 to $2 per sq ft (HomeGuide) |
Ranges come from HomeGuide's January 2026 attic guide and Fixr's 2025 spray foam guide. How much sealing the attic needs, the depth, the access and any removal decide the real number. We price the attic after seeing it, and that written figure is what you pay.
How It Works
1. Attic inspection
We measure existing depth, look for leaks, moisture, smoke residue and rodent damage, and check vents.
2. Written quote
Sealing, material, target R-value and any removal, line by line.
3. Seal
We close the leaks while the attic floor is still accessible.
4. Insulate
Baffles go in at the eaves, then insulation is blown or sprayed to depth with markers to show it.
5. Walk through
We show you the depth markers and photos of the sealed areas.
Attic Air Sealing & Insulation Questions
What R-value should my Santa Rosa attic be?
ENERGY STAR recommends R-49 for an uninsulated zone 3 attic, or adding R-38 over three to four inches already there.
Is blown-in or spray foam better for my attic?
For a standard vented attic, blown-in is usually better value. Foam on the roof deck makes sense when ducts or equipment are up there or there is no attic floor to fill.
My attic smells like smoke. Should the insulation go?
Smoke odor in insulation tends to linger. Removal and replacement is an option. Check with your insurer first about coverage.
How long does an attic job take?
Most sealing and blown-in jobs take a day. Removal or roof-deck foam can add a day or two.
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Get an Attic Air Sealing & Insulation Estimate
We check your attic and send a written price.