Fast, Reliable Blown-In Insulation Across Sunnyvale
Most blown-in insulation jobs in Sunnyvale run $2,400-$5,800 for a typical 1,100-1,600 square foot attic, and we can usually inspect and start work within 48 hours of your call. We dispatch crews from our San Francisco Bay Area office to Sunnyvale daily, so you’re not waiting on a contractor driving up from San Jose or across the bridge. Call (650) 381-1512 for a written price before any work starts - that’s Haven Standard Clause 1, no exceptions.
Sunnyvale’s housing stock is different from newer cities. The Lakewood, Morse-Mathilda, and Murphy-Ellis neighborhoods were built out between 1952 and 1975, mostly for Lockheed and Fairchild Semiconductor workers, and those post-war ranches carry little to no original wall insulation plus attic fill that’s settled to half its labeled R-value by now. We’ve insulated enough of them to know where the air bypasses hide and what Santa Clara County’s ADU energy checklist actually checks.
Why Topside Attic Insulation Union City Is Sunnyvale’s Preferred Blown-In Insulation Company
We’ve sealed and insulated over 9,000 homes since 2016, and a significant share of those have been in Sunnyvale’s pre-1978 ranches and their newer garage-conversion ADUs. Our Blown-In Insulation in Sunnyvale crews know the difference between a 1958 tract home on Morse Avenue and a 1964 Eichler-influenced ranch near Mathilda - the cavity depths vary, the soffit venting differs, and the dense-pack approach changes accordingly.
Sunnyvale customers find us through three-star reviews as often as five-star ones, which we appreciate. The detailed reviews mention specific things: the blower-door printout left on the kitchen counter, the photo record showing before-and-after attic conditions, the written scope signed before the truck was unloaded. That’s the documentation we deliver on every job, not on request.
Response time to Sunnyvale is typically same-day or next-day for inspections, with most blown-in installations completed in one day. Our technicians are background-checked, uniformed, and named - you’ll get a text when yours is en route, under Haven Standard: Arrive on schedule.
Our Blown-In Insulation Services in Sunnyvale
Blown-In Cellulose
We use GreenFiber cellulose on many Sunnyvale ranches because it dense-packs well into the empty 2×4 wall cavities we find behind original stucco in Lakewood and Morse-Mathilda. Cellulose is treated with borate for fire and pest resistance, and at R-3.2 to R-3.8 per inch, it fills shallow cavities more effectively than fiberglass batts that compress and lose labeled R-value. For attic top-ups, we blow cellulose over sealed top plates and can-light enclosures to hit current Title 24 minimums without stacking above the joists.
Blown-In Fiberglass
Owens Corning blown fiberglass is our choice for open attic floors in Sunnyvale where we’re topping settled fill to R-49. Fiberglass doesn’t absorb moisture the way cellulose can if a roof leak develops, and it performs predictably in Sunnyvale’s dry inland climate - 88-96°F summer afternoons with low humidity. We pair it with a radiant barrier on the roof deck when the attic gets direct solar gain, which is most of Sunnyvale east of El Camino Real.
Dense-Pack Wall Insulation
This is where Sunnyvale’s housing stock demands something beyond a standard attic blow. The 1950s-70s ranches in Murphy-Ellis and Morse-Mathilda were built with empty 2×4 stud cavities and no exterior sheathing - just stucco on lath directly over the studs. We cut 2-inch access ports through the stucco, dense-pack the cavity with GreenFiber cellulose at 3.5 pounds per cubic foot to eliminate settling, then patch with matching texture. Without this step, you’re heating and cooling the wall cavity itself. A typical 1,200 square foot ranch with full dense-pack wall retrofit runs $4,200-$7,800 in Sunnyvale.
Blown-In Top-Up
The most common call we get in Sunnyvale: “Our attic has insulation, but the house is still uncomfortable.” We inspect, measure settled depth, and find R-11 or R-19 where R-38 to R-49 should sit. But we don’t just blow more on top. Our Blown-In Insulation crew first seals top plates, wire penetrations, and open soffit eaves - the air bypasses that let conditioned air escape around the insulation. Then we top up to code. A blown-in top-up with air sealing typically runs $2,400-$4,200 in Sunnyvale’s smaller ranches.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Before
AfterTrusted Brands We Service in Sunnyvale
We stock materials from Owens Corning, Johns Manville, Knauf, GreenFiber, and Icynene - no proprietary lock-in, so we specify what fits your assembly rather than what moves our inventory. For Sunnyvale’s dual workload of 1950s ranch retrofits and ADU garage conversions, that means GreenFiber cellulose for dense-pack wall cavities, Owens Corning blown fiberglass for attic top-ups, and Icynene open-cell spray foam for the air-sealing layer that Santa Clara County’s ADU energy checklist requires on shared walls and slab edges. We carry these materials on our trucks, so we’re not waiting on a distributor run before starting your job.
Common Blown-In Insulation Problems We See in Sunnyvale Homes
- Topped-up attics with unsealed soffit eaves. In the Lakewood tract near Washington Park, we regularly find attics where a previous contractor blew new fill over old without sealing the open soffit vents. Sunnyvale’s afternoon heat - 88-96°F in summer - rises straight through those bypasses, making the insulation irrelevant. We seal first, then insulate. Always.
- Garage-conversion ADUs with no air barrier on the shared wall. The county checklist requires fire-blocking and air-sealing between ADU and main structure. We’ve seen blown-in fiberglass dumped into an unsealed cavity that the inspector failed immediately. The fix: Icynene spray foam on the shared wall, then dense-pack or batt insulation, then re-inspection.
- Missing radiant barriers on inland-facing roof decks. Sunnyvale gets substantially more direct solar gain than coastal markets. A pre-code ranch attic without a radiant barrier over the blown-in insulation is absorbing that heat all afternoon. We add radiant barrier when the roof deck geometry allows; the payback is measurable on PG&E bills.
- Slab-edge gaps in ADU conversions. The concrete slab in a converted garage has no vapor barrier and no insulation at the perimeter. We seal the slab edge with Icynene and add subfloor insulation where the checklist requires it - otherwise the ADU stays thermally connected to the ground, and the county won’t sign off.
Pricing for Blown-In Insulation in Sunnyvale, CA
| Service | Typical Range in Sunnyvale |
|---|---|
| Attic blown-in top-up (air sealing + R-38 to R-49) | $2,400 - $4,200 |
| Full attic blow (empty attic, air sealing, R-49) | $3,600 - $6,200 |
| Dense-pack wall insulation (1,200 sq ft ranch) | $4,200 - $7,800 |
| Garage-conversion ADU (air seal + insulate walls, ceiling, slab edge) | $5,800 - $11,400 |
| Radiant barrier addition with attic top-up | $1,200 - $2,400 additional |
These ranges reflect Sunnyvale’s typical 1,100-1,600 square foot post-war ranches. Larger homes, steep roof pitches, or hazmat conditions (rodent damage, asbestos vermiculite) move the price. We give you a written price before any work starts - flat, itemized, no revision unless you change the scope. Bring us any competing written estimate; we’ll read it with you and give a free second opinion. Estimates are free. Call (650) 381-1512.
We Also Serve Cities Near Sunnyvale
Our crews work daily in Mountain View, Santa Clara, Los Altos, and Milpitas - the same pre-1978 housing stock, the same Title 24 requirements, the same approach. Dispatch is coordinated from our San Francisco Bay Area office, so your appointment isn’t dependent on a crew finishing a job two cities away.
Serving Sunnyvale, CA - Our Local Coverage Area
We’re based in the Sunnyvale 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 - Blown-In Insulation in Sunnyvale
On most 1950s-60s Sunnyvale ranches, the attic top-up helps but the walls are the bigger leak. Those homes were built with empty 2×4 cavities behind original stucco - no insulation, no air barrier. We blower-door test to quantify it, but typically the wall retrofit cuts air leakage more than the attic blow alone. Call (650) 381-1512 for a test and written scope - estimates are free.
We air-seal the shared wall with Icynene spray foam, dense-pack or batt the stud cavities, insulate the ceiling assembly to R-38 minimum, and seal the slab edge - all documented with photos for the inspector. Santa Clara County’s ADU checklist specifically checks each of these points; skipping any one fails the energy compliance. We handle the full scope in one mobilization, not two.
Yes, more here than in foggier coastal markets. Sunnyvale’s inland location means direct afternoon sun on roof decks, and a radiant barrier can reduce attic surface temperatures by 20-30°F. We add it when the roof geometry allows access - typically $1,200-$2,400 on top of a blown-in job. The payback shows on summer PG&E bills.
Cellulose for wall cavities and cathedral ceilings where dense-packing matters; fiberglass for open attic floors where moisture resistance and long-term stability are priorities. Many Sunnyvale jobs use both - GreenFiber cellulose in the walls, Owens Corning fiberglass in the attic. We specify based on your assembly, not our inventory.
Insulation settles. A 1970s attic blown to R-30 may have compressed to R-15 or less by now. Plus, Sunnyvale’s open soffit eaves and unsealed top plates let conditioned air bypass the insulation entirely - the material is still there, but it’s not in contact with an air barrier. We measure settled depth, identify bypasses, and restore performance with sealed, topped-up fill. Call (650) 381-1512 for an inspection - estimates are free.
Written by Wes Okafor, Owner at Topside Attic Insulation Union City, serving Sunnyvale since 2016 under The Haven Standard.