Fast, Reliable Blown In Insulation Across San Francisco
Blown-in insulation in San Francisco typically costs $2,800 to $7,500 for a full attic, and $3,500 to $9,000 when dense-packing exterior walls, depending on square footage and current R-value. Most homes in the Richmond and Sunset need either a top-up over settled existing insulation or a full dense-pack in wall cavities that were never insulated when they were built. We’re the local Blown In Insulation team that handles both, and we’re in San Francisco neighborhoods every week. If you want a written price before any work starts, call us at (559) 245-9792. We answer live, 24 hours a day.
Why Alden Insulation San Francisco Is San Francisco’s Preferred Blown In Insulation Company
San Francisco homes are not like houses in the East Bay or down the Peninsula. They’re old, they’re tight to the property line, and they sit in marine air that never really dries out. Our crews work in these houses every week. We know what a 1920s stucco row house in the Outer Richmond is hiding behind its plaster, and we know how to insulate it without wrecking the exterior.
Every Alden job runs under The Garrison Standard. That means a background-checked, uniformed technician arrives inside the window we promised. You get a written price before a single tool comes off the truck. And every job carries the 365-Day Done Right Promise: if the insulation fails within a full year, we return at no charge. Bryce Holloway runs this location, and he holds the crew to that standard on every San Francisco job. When you call (559) 245-9792, a live person answers, not a voicemail tree.
Most attic insulation work in San Francisco is scheduled within 3 to 7 days. Wall dense-packing jobs typically start within one to two weeks because they require more prep. If you have a ceiling that’s open and ready, we can often start sooner.
Loose Fill Insulation in San Francisco
Loose Fill Insulation is the workhorse solution for Attic Insulation in San Francisco, especially in pre-1940 Victorians and Edwardians where the attic floor has odd joist spacing, knob-and-tube wiring, or awkward access. We blow loose fiberglass or cellulose across the attic floor to a consistent depth, which fills the irregular bays and covers gaps that batts can’t reach. In San Francisco, most loose fill attic jobs run $2,800 to $5,200 for a typical 1,200 to 1,800 square foot attic, including air sealing around penetrations.
Attic Top-Ups Over Settled Insulation
Many San Francisco attics have old fiberglass batts or loose fill that has settled to R-19 or less. We blow a fresh layer over the top to bring the assembly to R-38 or R-49. This is the fastest, most cost-effective job we do, and it usually takes one day.
Air Sealing Before the Blow
Marine air moves through every gap in an old ceiling. If we blow insulation without sealing the wall plates, wiring penetrations, and recessed light housings first, the R-value drops fast. We seal before we blow. That’s standard practice on every San Francisco job we take.
Blown In Insulation Contractors in San Francisco
Blown In Insulation Contractors in San Francisco have to solve a problem that doesn’t exist in newer suburbs: insulating wall cavities without tearing open lath-and-plaster. That’s where dense-packing comes in. We drill small access holes through the interior plaster or exterior siding, then pack the cavity with blown-in fiberglass or cellulose under pressure. It fills the void completely, including the odd-shaped bays above windows and behind built-ins. Dense-pack wall work in San Francisco typically runs $3,500 to $9,000 depending on the number of exterior walls and the access conditions.
Dense-Pack for Stucco Row Houses
In the Sunset and Richmond, where stucco covers most exteriors, we almost always work from the interior. Cutting from the outside means patching stucco, which never matches. We cut small holes in plaster, blow the cavity full, and patch to a paint-ready finish. The result is a wall that finally holds heat and blocks the damp air that’s been condensing behind furniture for decades.
Clearing Knob-and-Tube Before Insulating
Pre-1940 San Francisco homes often still have live knob-and-tube wiring in wall cavities. We do not blow insulation over live knob-and-tube. We identify it, flag it, and coordinate with a licensed electrician to decommission or replace the circuits before we insulate. Skipping this step violates code and creates a fire hazard. We won’t do it, and no reputable contractor should.
Trusted Brands We Service in San Francisco
We install products from brands homeowners can research on their own: Owens Corning, CertainTeed, Johns Manville, Knauf, Rockwool, Icynene, Demilec, and GreenFiber, and we handle Reflectix repair in San Francisco as well. For San Francisco’s climate, we most often recommend Owens Corning AttiCat fiberglass for attics because it’s non-absorbent and resists mold, and CertainTeed InsulSafe or GreenFiber cellulose for dense-pack walls because both pack tight and perform well in damp coastal air. We carry materials for San Francisco jobs in local stock, so we don’t have to wait on a distributor when your attic is already open. You’ll know the exact brand and product going into your home before we start.
Common Blown In Insulation Problems We See in San Francisco Homes
- Slumping batts in Sunset and Richmond stucco houses. Decades-old fiberglass batts fall away from the sheathing in wall cavities, leaving cold strips that condense moisture and grow mold behind wardrobes and headboards. Blown-in dense-pack is the only way to refill those voids without tearing the wall open.
- Knob-and-tube wiring in pre-1940 homes. Live knob-and-tube in wall cavities and attic floors makes insulating safely more complicated. We won’t blow over it. The wiring gets decommissioned first, then we insulate to code.
- Fog-belt moisture against unsealed wall plates. In the Outer Sunset and Richmond, marine air pushes through unsealed framing where walls meet floors. That damp air hits the back of the plaster and condenses. Air sealing before insulation is what actually stops the mold.
- Noise transfer in converted Victorians near Mission Street and the Castro. When a single-family Victorian gets split into flats, the original walls have zero acoustic value. Dense-pack blown-in insulation adds real mass and cuts airborne sound between units. It’s not a recording-studio fix, but it’s the single most effective retrofit you can do without reframing the wall.
Pricing for Blown In Insulation in San Francisco, CA
Attic loose fill in San Francisco runs $2,800 to $5,200. Dense-pack walls run $3,500 to $9,000 depending on how many exterior walls and what the access looks like. Combined attic and wall jobs on a full Victorian typically land between $6,000 and $12,000. What moves the number: square footage, current R-value, knob-and-tube remediation required, and whether we’re working from the interior or exterior. You get the written price before we start, and that’s the number on the invoice. Call (559) 245-9792 for a free estimate. No cost to walk the house and give you numbers.
We Also Serve Cities Near San Francisco
We run crews into Daly City, South San Francisco, Alameda, and Berkeley every week. If you’re on the Peninsula or in the East Bay and need Blown In Insulation work, call us. Our San Francisco scheduling covers the whole metro area.
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 Blown In Insulation in San Francisco
Yes. We dense-pack through small holes drilled into the plaster, leaving the original walls intact. Each hole is about 2 to 3 inches across, and we patch them to a paint-ready finish. The lath and plaster stay in place. This is the standard method for pre-1940 San Francisco homes, and we do it every week in the Richmond, Sunset, and Noe Valley. Call (559) 245-9792 to have us look at your specific walls.
Blown-in fiberglass slows the movement of warm, damp interior air into cold wall cavities, which is what causes condensation and mold in fog-belt homes. The key is air sealing first. In the Outer Richmond near Balboa Street, our crew pulled a slumping fiberglass batt from a 1920s stucco row house, and moisture had condensed along the back wall behind a wardrobe. We dense-packed the cavity with Owens Corning AttiCat blown-in fiberglass, cutting a small access hole from the interior to avoid disturbing the exterior stucco. We then air-sealed the wall plates to stop the marine air intrusion. The insulation works, but only if the air leaks are closed first. Get an exact assessment by calling (559) 245-9792.
Dense-packed insulation settles very little after installation because it’s installed under pressure. Loose fill on an attic floor can settle 2 to 4 percent over the first few years, which is why we blow to a slightly higher initial depth. In a three-story Edwardian, the bigger issue is that the upper-floor wall cavities were often never insulated at all. Dense-packing from the interior fixes that permanently. Call (559) 245-9792 for an exact quote, free.
Blown-in cellulose and fiberglass add real mass to a wall cavity and cut mid-range and high-frequency noise between units. It’s the most practical retrofit for a converted Victorian or Edwardian where opening the wall isn’t an option. That said, it’s not a complete acoustic isolation system. For significant low-frequency noise, like a neighbor’s subwoofer, you may also need a resilient channel and a second layer of drywall. We’ll tell you honestly what the insulation will and won’t do. Call (559) 245-9792 and we’ll walk the unit with you.
No. We will not blow insulation over live knob-and-tube wiring. It’s a code violation and a fire risk. The correct sequence is to have a licensed electrician decommission the knob-and-tube circuits first, then insulate. We can flag the issue during the estimate and coordinate with the electrician so the job runs in the right order. Call (559) 245-9792 and we’ll check your walls before you spend a dollar.
Written by Bryce Holloway, Owner at Alden Insulation San Francisco.