Spray Foam Insulation in San Francisco, CA
Spray foam insulation in San Francisco closes the gaps that let ocean air, fog, and neighborhood noise into older Bay Area homes. Most San Francisco houses were built before modern air-sealing standards, which means walls, rim joists, and attics leak conditioned air year-round. Thistledown Insulation San Francisco installs closed cell and open cell spray foam with a written price before any work starts, a live person answering every call at (341) 247-0222, and the 365-Day Done Right Promise behind every job.
We’re a Cedarwell-family company, founded in 2003, and our crews show up in uniform, lay drop cloths from the front door to the work area, and photograph the clean-up before leaving. Whether you’re in the Richmond District, Noe Valley, or out near Balboa Park, you’ll know exactly what product is going in, what it costs, and what your floors will look like when we’re done.
Trusted Spray Foam Insulation for San Francisco Homeowners
San Francisco homes sit in a marine climate where moisture moves through walls differently than it does in Sacramento or Walnut Creek. Fog rolls in most summer mornings, and older Victorians and Edwardians often have no continuous air barrier. That combination leads to drafts, cold rooms, and heating bills that climb even when the thermostat stays put. Spray Foam Insulation - San Francisco is one of the few products that insulates and air-seals in a single pass, which matters in a city where space is tight and every square foot counts.
Our crews have worked in homes throughout the Sunset, the Mission, Bernal Heights, and Glen Park. We understand what a 1920s lath-and-plaster wall needs versus a 1990s addition off the back. Every project gets a written price first, and our background-checked technicians wear shoe covers inside your home from the moment they step through the door. Call (341) 247-0222 and a live person answers, day or night.
Why San Francisco Homes Need Air Sealing
Most San Francisco homes lose conditioned air through the same paths: rim joists, attic hatches, recessed lights, and the gaps where old framing meets new additions. Spray foam expands into those cavities and stops air movement at the source. That’s a different approach than fiberglass batts, which filter air but don’t stop it.
Homes near the ocean also contend with salt air and high humidity. Closed cell foam acts as a vapor retarder, which helps protect framing in fog-heavy neighborhoods like the Outer Sunset and the Richmond.
The Thistledown Approach
We start by asking questions: Where are the cold spots? What rooms are over the garage? Does anyone in the house have chemical sensitivities? Then we recommend a product, not a brand first. Our installers are trained on Icynene, Demilec, and CertainTeed spray foam systems, and we match the product to the house, the family, and the budget.
You get a written number before we touch a rafter. If something isn’t done right within the first year, we make it right under the 365-Day Done Right Promise. No debate, no fine print.
Closed Cell Spray Foam Insulation
Closed Cell Spray Foam Insulation is a dense, rigid foam that insulates at roughly R-6.5 to R-7 per inch and acts as both an air barrier and a vapor barrier once cured. In San Francisco, we recommend closed cell foam in crawl spaces, rim joists, and exterior walls where moisture control matters as much as R-value. It adds structural strength to framing, which is a real benefit in older San Francisco homes where studs may have settled or shifted over 80 or 100 years.
Thistledown Insulation San Francisco installs closed cell foam in basements, garages, and anywhere moisture from fog or soil is a concern. Pricing for closed cell spray foam in San Francisco typically runs $2.20 to $3.80 per board foot installed, depending on depth, access, and the condition of the framing, so you know how much Spray Foam Insulation costs upfront. Your exact number is in writing before any work begins.
Moisture Control in Fog-Belt Neighborhoods
Homes west of Twin Peaks live with fog for much of the year. Closed cell foam stops vapor drive from the outside, which reduces the chance of condensation forming inside wall cavities. In neighborhoods like Parkside and the Outer Richmond, that’s a meaningful difference.
Structural Benefits for Older Framing
Closed cell foam bonds to studs and sheathing and stiffens the wall assembly. For San Francisco homes built before modern shear-wall standards, that added rigidity is a quiet bonus on top of the insulation value.
Open Cell Spray Foam
Open Cell Spray Foam is a lighter, softer foam that expands significantly and insulates at roughly R-3.5 to R-4 per inch. It’s an air barrier but not a vapor barrier, which makes it a strong fit for attic rooflines and interior walls in San Francisco where you want air sealing without trapping moisture. It’s also noticeably quieter than closed cell foam, which matters in dense neighborhoods where Muni buses and street noise bleed through walls.
Thistledown Insulation San Francisco installs open cell foam in attics, interior partition walls, and sound-sensitive areas like home offices and nurseries. Open cell spray foam in San Francisco typically runs $1.10 to $2.10 per board foot installed. You’ll receive a written price before we begin, every time.
Sound Dampening for City Living
Open cell foam absorbs sound better than closed cell. In neighborhoods like the Mission or along the corridors in SoMa, open cell in an interior wall can reduce the noise that travels between units or from the street into a bedroom.
Attic Roofline Applications
When we spray open cell foam directly against the roof deck, we bring the attic inside the conditioned envelope. That’s useful in San Francisco homes where the furnace or ductwork lives in the attic, since ducts stop bleeding heat into an unconditioned space.
Spray Foam Insulation Contractors
Spray Foam Insulation Contractors are licensed crews who install expanding foam insulation, and choosing one in San Francisco means filtering for experience with old framing, tight access, and lead-paint-era construction. The wrong contractor can overspray, under-cure, or leave off-ratio foam that smells for months. The right one shows up with the right rig, the right training, and a plan for keeping your home clean during the work.
Thistledown Insulation San Francisco has installed spray foam in San Francisco homes since 2003 as part of the Cedarwell family of independently owned insulation companies. Our technicians are background-checked and uniformed, and every visit follows the Cedarwell Care Promise: shoe covers, drop cloths, and a photo of the clean-up before we leave. Spray foam installation in San Francisco typically runs $1,500 to $9,000 depending on the area sprayed, and you’ll have your exact written number before we start.
What to Ask Any Spray Foam Contractor
Ask whether the crew is trained on the specific product being installed. Ask whether they’ll leave the job site clean enough for a toddler to crawl across. Ask what happens if the foam doesn’t cure correctly. We answer all three before you sign anything.
Why Experience With Old Homes Matters
Many San Francisco homes have balloon framing, knob-and-tube remnants, or plaster walls that crack under expansion pressure. Our crews know how to work around those conditions and when to recommend open cell over closed cell to avoid stress on old materials.
Spray Foam Attic Insulation
Spray Foam Attic Insulation is applied directly to the underside of the roof deck, which turns the attic into a conditioned space instead of a hot, drafty buffer zone. In San Francisco, where many homes have furnaces and ducts running through the attic, this makes an immediate difference in how hard your heating system works. It also reduces the stack effect that pulls conditioned air up and out of the house all winter.
Thistledown Insulation San Francisco installs spray foam attic insulation in homes from the Outer Sunset to Bayview. Attic spray foam in San Francisco typically ranges from $3,500 to $9,500 for an average 1,000 to 1,500 square foot attic, with your written price provided before any foam is mixed.
Duct Sealing Benefits
When ducts run through a spray-foamed attic, they operate inside the home’s thermal envelope. That means less heat lost through duct walls and a furnace that cycles less often. In San Francisco’s mild climate, that often translates to more even temperatures between floors.
Reducing the Stack Effect
Warm air rises and leaks out through attic hatches, recessed lights, and framing gaps. Spray foam seals those leak paths at the roofline, which keeps air you’ve already heated inside the living space.
Spray Foam Wall Insulation
Spray Foam Wall Insulation fills wall cavities completely, including the gaps and voids that batts leave behind around outlets, plumbing, and framing. In San Francisco, most exterior walls are uninsulated or under-insulated, and the fog-driven moisture that cycles through those cavities every summer shortens the life of any wall assembly. Spray foam stops air movement and, with closed cell, helps manage moisture at the same time.
Thistledown Insulation San Francisco installs Spray Foam Insulation - Albany and San Francisco wall insulation in existing homes, additons, and gut-remodel projects. Wall spray foam in San Francisco typically costs $2.10 to $4.20 per square foot of wall area, depending on access, foam type, and framing condition. Every project gets a written price before work begins.
Retrofit Walls in Older Homes
Retrofitting walls means drilling access holes, spraying foam, and patching carefully. We protect floors and furniture, and we ask before we move anything. The finished wall gets patched flush and ready for paint.
New Construction and Additions
For additions and remodels in San Francisco, spray foam lets you hit modern energy code air-sealing targets without layering multiple products. We coordinate with your general contractor and show up when the framing is ready.
Rim Joist Spray Foam
Rim Joist Spray Foam seals the band of framing where the floor meets the foundation, which is one of the leakiest parts of any San Francisco home. Air enters there from outside, travels through the floor system, and shows up as cold floors and drafty baseboards. Closed cell foam is the standard fix: it insulates, air-seals, and blocks moisture from the foundation.
Thistledown Insulation San Francisco seals rim joists in basements, crawl spaces, and garages throughout the city. Rim joist spray foam in San Francisco typically runs $900 to $2,800 for a standard home, depending on linear footage and access conditions. Your written price comes before the spray rig ever fires up.
Cold Floor Fixes
If the floor above your garage or crawl space feels cold in January, the rim joist is often the culprit. Sealing it stops the cold air that travels through the floor assembly, and rooms above garages warm up noticeably.
Moisture and Pest Barriers
Closed cell foam at the rim also reduces the path for moisture and insects. In San Francisco’s damp basements and hillside crawl spaces, that protection matters as much as the R-value.
Crawl Space Spray Foam Insulation
Crawl Space Spray Foam Insulation seals the under-floor area against moisture, cold air, and the musty smell that rises into San Francisco living rooms every time the heat kicks on. Most San Francisco crawl spaces are vented, which means fog-season air moves through them freely and carries moisture straight into floor framing. Spraying closed cell foam on crawl space walls or the underside of the floor changes that dynamic.
Thistledown Insulation San Francisco installs Spray Foam Insulation in San Bruno and crawl space spray foam insulation in homes from Noe Valley to the Excelsior. Crawl space spray foam in San Francisco generally runs $2,200 to $6,800 depending on square footage, access height, and existing moisture conditions. We give you a written number before any work starts.
Encapsulation vs. Floor Insulation
Some crawl spaces are better served by sealing the walls and bringing the space inside the house. Others need foam under the floor only. We assess the space, check for standing moisture, and recommend the approach that fits your home and your budget.
Fog-Season Moisture Control
San Francisco crawl spaces run damp from June through August. Closed cell foam resists moisture and won’t sag or mold the way fiberglass does in humid conditions. That’s why it’s our default recommendation under San Francisco homes.
Garage Spray Foam Insulation
Garage Spray Foam Insulation turns an uninsulated garage into a usable room, a warmer workshop, or a quieter buffer between the street and the rest of the house. In San Francisco, many garages sit directly below bedrooms, and the cold air trapped in the garage radiates up through the floor all winter. Spray foam on the garage walls and ceiling stops that heat loss and cuts street noise dramatically.
Thistledown Insulation San Francisco installs garage spray foam insulation in homes across the city. Garage spray foam in San Francisco typically ranges from $1,800 to $5,500 depending on garage size, wall condition, and whether the ceiling is included. Call (341) 247-0222 and we’ll give you a written price before any foam is sprayed.
Bedrooms Above Garages
Rooms above an uninsulated garage are often the coldest in the house. Sealing and insulating the garage ceiling with closed cell foam stops the cold from rising through the floor system and makes those bedrooms comfortable year-round.
Noise Reduction From the Street
Spray foam, especially open cell, absorbs sound. In neighborhoods like the Inner Sunset or along busy corridors like Geary or 19th Avenue, insulating the garage wall that faces the street quiets the whole front of the house.
Brands We Service
We install Icynene spray foam, which includes both open cell and closed cell formulations suited to San Francisco’s marine climate. Icynene’s open cell foam is a frequent choice for attic rooflines where sound control and air sealing matter more than vapor resistance. Our crews are trained on Icynene’s application temperatures, expansion rates, and cure times, so the foam goes in right the first time.
We also work with Demilec closed cell products, which we recommend for crawl spaces, rim joists, and garage walls where moisture is a factor. And for homes where a specific manufacturer is specified on a remodel or energy-efficiency program, we install CertainTeed spray foam systems. Whether you have a brand preference or want us to recommend the right product for your San Francisco home, we can help.
Signs You Need a Pro Right Now
- Cold floors in rooms above the garage. When the floor stays cold even with the heat on, the garage ceiling or rim joist is leaking conditioned air. Spray foam seals those paths and keeps the floor from siphoning heat out of the room.
- Drafts around baseboards and outlets in winter. Air moving through wall cavities and rim joists shows up at the edges of rooms. If you can feel air moving near baseboards on a windy day, your wall assembly has gaps that spray foam can close.
- A musty smell that returns every summer. Fog-season moisture entering the crawl space or attic causes that persistent smell. Spray foam, especially closed cell, blocks the moisture path and keeps the air inside your home cleaner and drier.
- Rooms that never match the thermostat. When one bedroom is always colder than the hallway, the problem is often air movement through the walls or ceiling, not the thermostat itself. Air sealing with spray foam evens out temperatures room by room.
- Higher heating bills than your neighbors with similar homes. San Francisco homes vary, but if your PG&E bill climbs every winter while your furnace runs constantly, air leakage is a likely cause. Sealing the attic, rim joists, and walls with spray foam reduces the load on your heating system.
Our Process, Step by Step
- 1
You call and a person answers. We don’t use voicemail trees. A live person answers 24/7, listens to what’s going on, and schedules a visit at a time that works for your family.
- 2
We assess your home and listen. Our technician walks the attic, crawl space, or garage, asks where the cold spots are, and checks for moisture, old wiring, and access issues. We ask before we move anything, and we wear shoe covers inside your home.
- 3
You get a written price. Before any work starts, we hand you a specific number. Not a range, not an estimate with fine print. The price is in writing, and it includes the shoe covers, the drop cloths, and the clean-up photo.
- 4
We install the foam carefully. Our background-checked, uniformed technicians mask off the work area, protect your floors and furniture, and use quiet tools when children are sleeping. We spray to the specified depth, check for voids, and let the foam cure properly before we wrap up.
- 5
We clean up and show you the proof. We sweep, vacuum, and photograph the area before we leave. If anything isn’t right within the first year, the 365-Day Done Right Promise means we make it right. No debate.
How Much Does Spray Foam Insulation Cost in San Francisco?
A typical spray foam insulation project in San Francisco runs $2,500 to $8,500 depending on the area being sprayed. Rim joist sealing lands on the lower end, usually $900 to $2,800, while a full attic roofline spray runs $3,500 to $9,500. Wall retrofits fall in the middle, around $2.10 to $4.20 per square foot, and crawl space work typically runs $2,200 to $6,800.
What affects the price: access height, framing condition, the foam type, and the square footage. Closed cell costs more per board foot than open cell. What doesn’t affect the price: hidden fees. Every Thistledown customer gets a written number before any work starts, and that number doesn’t move unless the scope changes and you approve it first.
To avoid overpaying, get a specific written quote rather than a ballpark range, and ask whether the quote includes clean-up and prep. Ours always does. A free estimate from Thistledown Insulation San Francisco includes the full assessment, the product recommendation, and the exact written price.
Our Service Area Near San Francisco
Thistledown Insulation San Francisco serves the entire city, from the Outer Richmond to Bayview and everywhere between. We also serve nearby communities including Spray Foam Insulation in Richmond, Spray Foam Insulation in Hayward, Daly City, South San Francisco, and San Bruno. Typical response time for an estimate is within 48 hours, and emergency calls are answered by a live person around the clock.
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.
Frequently Asked Questions About Spray Foam Insulation in San Francisco
Spray foam insulation is a two-part liquid that expands on contact and cures into a solid foam that insulates and air-seals in one step. It fills gaps, cracks, and voids that batts and blown-in products leave behind. The two main types are open cell, which is softer and sound-absorbent, and closed cell, which is denser and acts as a moisture barrier.
Most San Francisco spray foam projects take one day from setup to clean-up. A rim joist or crawl space job may finish in four to six hours, while a full attic roofline can take a full day. We give you a clear timeline with your written price before any work begins.
Spray foam insulation in San Francisco typically costs $2,500 to $8,500 for a standard project, with smaller rim joist jobs starting around $900 and full attic sprays running up to $9,500 depending on size and foam type. Your exact written price is provided before any work starts. Call (341) 247-0222 for a free estimate.
Yes, our crews are trained on Icynene and Demilec spray foam systems, plus CertainTeed spray foam. We match the product to your San Francisco home, your moisture conditions, and your family’s needs. If you have a brand preference, we’ll work with it.
Spray foam is safe once fully cured, which typically takes 24 hours. During installation, we seal off the work area and recommend that people and pets stay out of the immediate space until the foam has cured and the area has been ventilated. Where pet-safe product options exist, we’ll choose them, so the dog can be home during the job.
Yes. Every spray foam insulation project from Thistledown Insulation San Francisco is backed by the 365-Day Done Right Promise. If it’s not done right within the first year, we make it right. No debate, no fine print.
Clear a path from the front door to the attic hatch, crawl space entry, or garage wall, and move any fragile items away from the work area. We bring drop cloths and shoe covers, and we ask before we move anything. If you have children napping or pets at home, let us know and we’ll plan the work around quiet hours.
Schedule Your Spray Foam Insulation Service in San Francisco Today
Call (341) 247-0222 and a live person will answer, day or night. We’ll schedule a free estimate, walk your San Francisco home with you, and hand you a written price before any work begins. If it’s not done right, the 365-Day Done Right Promise means we make it right.
Written by Neil Barron, Owner at Thistledown Insulation San Francisco, serving San Francisco since 2003.