Insulation Company in San Francisco, CA
Woolsey Attic Insulation handles attic and spray foam insulation across San Francisco, from the fog-soaked Outer Sunset to the wind-buffeted slopes of Potrero Hill. Most San Francisco homes were built between 1880 and 1920 with no original insulation anywhere in the envelope, so the work here is rarely a simple top-up. It’s an air-sealing and moisture-management job first, and an insulation job second. If you’re wondering what a job in your building will actually take, call (325) 240-5411 and we’ll walk you through it plainly.
Why San Francisco Homes Are Different
San Francisco’s housing stock is dominated by Victorian and Edwardian row houses built with balloon framing: continuous wall cavities running from foundation to attic, no fire blocking, no insulation, and plaster-on-lath interior finishes. Because most of these homes share party walls on both sides, the exterior walls you could insulate are often limited to the front and rear facades. The real thermal leaks sit elsewhere. Uninsulated subfloor crawlspaces and attics let conditioned air escape straight up or straight down, while the shared walls act as thermal buffers that mask just how much heat you’re losing through the top and bottom of the building.
The climate makes this worse in a very specific way. San Francisco rarely sees temperatures below 40°F, so the heating load is modest by national standards. What defines the comfort problem here is the marine layer. For six or more months a year, the western half of the city sits at 50 – 58°F with near-100% humidity. In neighborhoods like the Outer Sunset, Richmond, and West Portal, that means uninsulated floors and attics feel bone-cold far out of proportion to the actual temperature. The air itself is damp, and it moves through balloon-frame top-plate gaps and unsealed attic floors constantly. A furnace upgrade won’t fix that. Sealing the leaks and adding insulation will.
There’s also the moisture failure mode specific to fog-belt neighborhoods. Contractors working the Outer Sunset regularly find attic insulation jobs where the real problem is condensation, not heat loss. Fog-saturated air infiltrates through top-plate gaps and condenses on the underside of cold roof sheathing. If blown-in cellulose is installed without proper air-sealing and venting strategy, it can absorb that moisture and become a sponge. That’s a failure mode you don’t see across the bay in Oakland or San Jose. It’s why we always assess the existing venting and air-seal before we recommend any material.
Our Main San Francisco Services
Two services account for nearly every call we take from San Francisco homeowners. Each has its own page with full pricing and job details.
Attic Insulation in San Francisco
Most San Francisco attics are unconditioned, finished as storage, or converted into living space with no insulation at the roof deck. The job usually starts with sealing top-plate gaps, recessed light housings, and plumbing penetrations, then adding blown-in insulation to the attic floor. In fog-belt neighborhoods, we also check whether the existing venting is moving enough air to keep sheathing dry. The target is typically R-38 to R-49, which meets both San Francisco code and the practical reality of damp, cool air pressing against the ceiling below. Full details are on our city-specific page: Attic Insulation in San Francisco.
Spray Foam Insulation in San Francisco
Spray foam, a two-part liquid that expands on contact and seals gaps airtight, earns its cost in San Francisco when the attic is living space or the home has a flat roof with no vented attic at all. It insulates and air-seals in one step, which is exactly what a converted Victorian attic needs. Because exterior wall access is blocked by party walls and protected historic facades, spray foam is also used to insulate rim joists and floor cavities from the crawlspace side in some buildings. See our dedicated page: Spray Foam Insulation in San Francisco.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in San Francisco
We install and service materials from Owens Corning, Johns Manville, Knauf, and Rockwool, choosing the product that fits the home rather than whatever happens to be on the truck. Our Bay Area stock covers the most common blown-in and spray foam products, so San Francisco jobs rarely wait on shipping. See our brands for the full picture.
Pricing for Insulation Company in San Francisco, CA
Every San Francisco home is different, and any price you see online is a starting point, not a bid. The table below reflects what we typically see across the city. You’ll get a written, itemized price before any work starts, and that number is the number you pay.
| Service | Typical range in San Francisco |
|---|---|
| Attic air sealing and insulation package | $2,500 – $5,500 |
| Attic insulation removal (old or damaged) | $1,200 – $3,000 |
| Blown-in fiberglass attic insulation | $1,800 – $3,800 |
| Blown-in cellulose attic insulation | $1,600 – $3,400 |
| Spray foam attic insulation | $4,800 – $12,000 |
| Spray foam rim joist insulation | $1,400 – $3,000 |
| Subfloor and crawlspace insulation | $1,500 – $4,200 |
| Full envelope insulation in a Victorian | $9,000 – $22,000 |
What pushes a San Francisco price up is access. Attics in Victorian rows are rarely full-height spaces with easy entry. Many are reached through a closet hatch, and blown-in material has to be carried up narrow stairs or hosed through a small opening from the street. Multi-unit buildings, shared attics, and any sign of mold or active moisture add time. That’s why we give you the exact written number before any work starts, not after the crew arrives.
Neighborhoods We Serve in San Francisco
We work throughout San Francisco, including the fog-belt neighborhoods where moisture management matters most.
- Outer Sunset
- Richmond
- West Portal
- Noe Valley
- Potrero Hill
Most San Francisco jobs can be scheduled within a week, with same-week appointments available during slower seasons. If you call before noon, we can often get a technician to your home the same day for an assessment.
Service Area – Cities Near San Francisco
We also cover homeowners across the Bay Area, including Daly City, CA just south of the city line, South San Francisco, CA along the Peninsula, Sausalito, CA across the Golden Gate, and Alameda, CA across the Bay Bridge. Our Bay Area office coordinates dispatch, and crews serve San Francisco locally every day.
Serving San Francisco, CA - Our Local Coverage Area
We’re based in the San Francisco area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Insulation Company in San Francisco
In most cases, the heat is escaping through the attic or the floor before the room ever warms up. San Francisco’s row houses were built with no insulation and shared walls that mask the loss. Air-sealing the top and bottom of the envelope is the fix, not a bigger furnace. Call (325) 240-5411 for an assessment.
Most insulation-only jobs do not require a permit, including blown-in attic work and subfloor insulation. If the project is part of a larger remodel that already has a permit, we work with your contractor. We’ll tell you up front if your specific project needs one, and that’s part of the written price.
Yes. Shared party walls are actually a reason to focus on the attic and subfloor, where the heat is truly leaving. Blown-in dense-pack cellulose through small-bore drilling is the typical wall retrofit path for Victorian and Edwardian shells, and we can assess whether your building qualifies.
Questions about your specific building, street, or strata? Call (325) 240-5411 for a free estimate. We’ll give you a written price before any work starts, in writing, every time.
What happens when you call
- 1A real person answersNo phone trees - talk to a local insulation pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3A background-checked tech heads outLicensed & insured, typically within 30-60 min.
- 4You approve before work beginsNothing starts until you say go.
What San Francisco Customers Say
"Insulation job was done well. Scheduling took a little longer than I'd have liked, they were booked out a couple weeks. But once they came it was quick and the house is cozier."
- Felicia Grant"The guy didn't try to sell me on foaming the whole house. He said the attic was where I'd actually feel it and left it at that. Honest, and he was right, our bills dropped."
- Angela Ruiz"Drafty old house that never felt comfortable. After the attic and some air sealing it's a different place. On time, clean, and the quote didn't change. Wish I'd done it years ago."
- Dmitri Kozlov