Attic Insulation in Sunnyvale - Same-Day Service, Done Right the First Time

Insulation in Sunnyvale, CA

Crawl space encapsulation and vapor barrier work in Sunnyvale starts with homes built between the 1950s and 1970s that were never sealed to modern standards, leaving dirt-floored crawl spaces vented directly to summer humidity and winter groundwater. We’re Envelope Insulation Co., and we treat air sealing as a hard prerequisite before any insulation goes in, publishing before-and-after blower-door numbers on every job so you can see the performance change you paid for. For a written price before any work starts, call us at (669) 280-8103.

Call (669) 280-8103

Why Sunnyvale Homes Are Different

Sunnyvale sits far enough inland from the coast that summer afternoons regularly hit the mid-80s to low 90s, measurably hotter than Palo Alto or San Francisco, which means under-insulated older homes face real cooling loads, not just winter heat loss. The dominant housing stock is post-war single-story ranch homes built with 2×4 framing and little to no wall insulation, since contractors of that era had no code requirement and the mild climate gave them cover.

The Birdland neighborhood contains a documented cluster of Eichler homes whose flat, low-slope roofs have no conventional attic cavity, making standard blow-in insulation impossible and requiring exterior rigid foam or spray foam applied to the roof deck. Beyond Eichlers, Silicon Valley’s housing-cost pressure has produced one of the Bay Area’s highest per-capita ADU and renovation permit rates, and every permitted project triggers mandatory Title 24 insulation compliance. PG&E serves Sunnyvale at some of California’s highest residential electricity rates, compressing the payback period on insulation retrofits.

Our Main Sunnyvale Services

Most Sunnyvale homeowners who call us start with attic work or spray foam, especially for Eichler and ranch-style homes with unique access challenges.

Attic Insulation in Sunnyvale

Attic insulation in Sunnyvale means working with shallow roof pitches, limited venting in older ranches, and the occasional Eichler with no attic at all. We begin with a blower-door test to measure how much conditioned air you’re losing, seal top plates and penetrations, then install Owens Corning or Johns Manville products to the depth Title 24 requires for your permit scope. Every job closes with a Documented Photo Record and, when applicable, before-and-after blower-door readings.

Attic Insulation in Sunnyvale

Spray Foam Insulation in Sunnyvale

Spray foam is often the only viable option for Eichler homes in Birdland and other flat-roof neighborhoods where there’s no attic to access. We apply closed-cell spray foam directly to the underside of roof sheathing from inside, creating an unvented conditioned assembly that meets Title 24 without touching the roofing membrane. For standard homes, open-cell foam in walls and rim joists stops air movement that fiberglass alone cannot.

Spray Foam Insulation in Sunnyvale

Blown-In Insulation in Sunnyvale

Blown-in insulation works best in Sunnyvale’s ranch homes with accessible attics and adequate ventilation paths. We use Knauf or GreenFiber cellulose, installed to a settled density that resists settling over time, but only after we’ve sealed the attic floor with caulk and foam at all top plates, wire penetrations, and duct boots. Without that sealing step, the new insulation simply filters the air leaking through.

Blown-In Insulation in Sunnyvale

Crawl Space Encapsulation & Vapor Barrier in Sunnyvale

Sunnyvale’s 1950s-1970s ranch homes were built with vented crawl spaces and dirt floors that exchange moisture freely with the soil, and our clay-heavy soils hold groundwater longer than the sandy loams found closer to the Bay. A proper Crawl Space Encapsulation & Vapor Barrier job here means sealing that entire envelope, not just laying down plastic, because summer humidity and winter rains create condensation cycles that destroy floor joists and breed mold in unsealed spaces.

Crawl Space Vapor Barrier

Signs you need it

Your crawl space has standing water after winter rains, white mineral deposits on foundation walls, or a musty smell that rises through floor registers.

What it costs in Sunnyvale

A 6-mil or thicker polyethylene vapor barrier installed over bare dirt in a typical Sunnyvale ranch crawl space runs $1,800 to $3,200 depending on square footage and whether we need to grade the soil first.

How we do it

We remove debris, grade the soil to drain toward a sump location if needed, lay 10-mil reinforced polyethylene with sealed seams and mechanical fastening at walls, and seal all penetrations with compatible tape.

Crawl Space Encapsulation

Signs you need it

Your hardwood floors are cupping, HVAC ducts in the crawl space show corrosion, or you’ve had rodent activity that compromised the vapor barrier.

What it costs in Sunnyvale

Full encapsulation with rigid foam wall insulation, sealed crawl space door, conditioned air supply, and dehumidification for a standard Sunnyvale ranch runs $5,500 to $9,500.

How we do it

We install rigid XPS foam on foundation walls, seal rim joists with closed-cell spray foam, install a heavy-duty vapor barrier lapped and sealed at all edges, add a mechanical dehumidifier with condensate pump, and bring in a small conditioned air supply to maintain positive pressure.

What Crawl Space Encapsulation & Vapor Barrier Costs in Sunnyvale

How long does crawl space encapsulation take in Sunnyvale?

A full encapsulation on a standard 1,200-square-foot ranch crawl space takes three to five days, including drying time for sealants. Vapor barrier-only jobs finish in one day. We coordinate with your schedule and provide a written timeline before starting.

Will encapsulation fix my musty smell?

Yes, if the smell originates from soil moisture and mold growth in the crawl space, because sealing the envelope and adding dehumidification stops the moisture source. Persistent smells from sewer lines or plumbing leaks require a plumber first. Call (669) 280-8103 and we’ll diagnose the source during our free estimate.

Radiant Barrier Installation in Sunnyvale

Sunnyvale’s inland position means summer attic temperatures regularly exceed 140°F, and ranch homes with dark shingle roofs absorb that heat directly into under-insulated ceiling assemblies. A Radiant Barrier Installation reflects that radiant heat back toward the roof deck rather than letting it conduct through the drywall, which is especially effective in homes where adding more insulation depth is limited by shallow rafter bays or recessed can lights.

Attic Radiant Barrier

Signs you need it

Your upstairs rooms run 10°F hotter than downstairs by mid-afternoon, your AC cycles constantly in summer, or you’ve added insulation but still feel radiant heat from the ceiling.

What it costs in Sunnyvale

Radiant barrier foil stapled to rafters or laid over existing attic insulation in a typical Sunnyvale ranch runs $1,200 to $2,400 depending on attic square footage and accessibility.

How we do it

We install perforated radiant barrier foil with proper air gaps, ensuring at least 3/4 inch of clearance from roof decking to allow attic ventilation to function, and we never install over unsealed air leaks that would allow moisture to condense against the foil.

Radiant Barrier Roof Deck

Signs you need it

You’re re-roofing a Sunnyvale home and want to address heat gain at the source rather than adding more attic insulation that compresses in shallow bays.

What it costs in Sunnyvale

Radiant barrier roof decking or spray-applied radiant coating during a re-roof project runs $2,800 to $4,500 for a standard 1,500-square-foot roof footprint.

How we do it

We specify OSB with factory-applied radiant barrier lamination or apply a spray radiant coating to the underside of existing roof decking during tear-off, always paired with proper ventilation calculations to prevent moisture trapping.

What Radiant Barrier Installation Costs in Sunnyvale

Does radiant barrier work with existing insulation?

Yes, radiant barrier complements rather than replaces insulation by addressing the radiant heat transfer that fiberglass and cellulose don’t block effectively. We install it after air sealing and often recommend it when your attic already has adequate R-value but summer comfort remains poor.

Can radiant barrier go in my Eichler?

No, Eichler homes with flat roofs and no attic cavity have no rafter bay to install radiant barrier; spray foam on the roof deck is the correct approach for those assemblies. We assess roof geometry during our free estimate and specify accordingly.

Insulation Removal & Replacement in Sunnyvale

Sunnyvale’s older housing stock often contains insulation installed before modern standards, and the mild climate that once excused thin R-values now works against homeowners facing PG&E’s top-tier electricity rates. Insulation Removal & Replacement is common after rodent infestation, water damage from failed HVAC condensate lines, or when vermiculite from the 1950s-1980s is discovered during renovation.

Contaminated Insulation Removal

Signs you need it

Your attic insulation shows urine staining, compressed trails, or a strong ammonia smell indicating rodent contamination that standard cleaning cannot address.

What it costs in Sunnyvale

Removal and disposal of contaminated batt or blown insulation from a typical Sunnyvale ranch attic, with HEPA containment, runs $1,600 to $3,000 depending on depth and square footage.

How we do it

We establish negative air pressure with HEPA filtration, remove insulation in sealed bags, apply enzymatic cleaner to exposed framing, and provide photographic documentation of the cleaned substrate before any new insulation is specified.

Insulation Replacement

Signs you need it

Your removed insulation revealed R-11 or less in 2×4 walls, settled blown cellulose below joist tops, or gaps where electricians and plumbers displaced batts decades ago.

What it costs in Sunnyvale

Replacement with modern fiberglass, cellulose, or mineral wool to current Title 24 standards runs $2,200 to $4,800 for attic spaces and $3,500 to $6,500 for wall insulation in a typical 1,200-square-foot ranch.

How we do it

We air seal all top plates, penetrations, and duct boots first, then install specified insulation to the depth and density required by your permit’s Title 24 compliance form, closing with blower-door verification and a Documented Photo Record.

What Insulation Removal & Replacement Costs in Sunnyvale

Do you test for asbestos before removal?

Yes, we require testing for vermiculite and pre-1990 batt insulation before disturbing it, and we use certified abatement partners if asbestos is present. We handle the sampling and lab coordination; results typically return in 48 hours.

How soon can new insulation go in?

New insulation installs immediately after the attic is cleaned, sealed, and inspected, often the same day for removal-only jobs or the following morning for full replacement. We schedule both phases in your written scope so there’s no gap.

Attic Air Sealing in Sunnyvale

Sunnyvale’s pre-Title 24 homes were built with deliberate ventilation gaps at top plates, recessed can lights cut into ceilings with no airtight housings, and flex duct boots pulling conditioned air directly into the attic. Attic Air Sealing is the single most cost-effective upgrade for these homes because it stops the stack effect that pulls cool air out in summer and heated air out in winter, and we never install new insulation over an unsealed attic floor.

Top Plate & Penetration Sealing

Signs you need it

Your blower-door test shows excessive air leakage, you feel drafts at interior wall bases, or your attic insulation has dark staining where filtered air passed through.

What it costs in Sunnyvale

Sealing all top plates, wire penetrations, plumbing stacks, and chimney chases in a typical Sunnyvale ranch attic runs $1,400 to $2,600.

How we do it

We locate every top plate with blower-door-directed infrared imaging, seal gaps with fire-rated caulk and expanding foam, install fire-blocking where required by code, and verify with a post-sealing blower-door test.

Can Light & Duct Boot Sealing

Signs you need it

Your recessed lights are original non-IC housings, your HVAC ducts show dust accumulation on attic-facing surfaces, or rooms farthest from the air handler never reach set temperature.

What it costs in Sunnyvale

Installing airtight LED retrofit housings and sealing all flex duct connections with mastic runs $1,800 to $3,400 for a typical 10-fixture, 3-zone system.

How we do it

We replace non-AT housings with airtight IC-rated LED modules, seal duct boots with fiber-reinforced mastic and mechanical straps, and pressure-balance the system to verify no post-sealing leaks.

What Attic Air Sealing Costs in Sunnyvale

Will air sealing alone lower my bill?

Yes, typically 10-20% in homes with significant leakage, though we pair it with insulation upgrades for full Title 24 compliance and maximum comfort. The blower-door number tells the story: a 50% reduction in CFM50 is a 50% reduction in conditioned air you’re paying to replace.

Do I need to leave during air sealing?

No, the work is in the attic with minimal interior disruption, though we ask that you avoid the work zone for safety. The blower-door test runs for about 30 minutes and requires all windows and doors to be closed.

Wall Insulation in Sunnyvale

Sunnyvale’s 1950s-1970s tract homes were built with 2×4 walls and no insulation, and the garage-to-ADU conversions common here legally require full Title 24 wall insulation upgrades that original construction never included. Wall Insulation in these homes means working from the inside to avoid disturbing stucco or siding, and matching the insulation strategy to whether the wall is above grade, below grade, or shared with an unconditioned garage.

Drill & Fill Wall Insulation

Signs you need it

Your exterior walls feel cold to the touch in winter, your home fails Title 24 compliance for a permitted ADU conversion, or you’ve removed interior drywall and found empty stud bays.

What it costs in Sunnyvale

Drilling and filling 2×4 exterior walls with dense-pack cellulose or fiberglass in a typical 1,200-square-foot Sunnyvale ranch runs $3,500 to $6,500 including patching and texture matching.

How we do it

We drill 2-inch holes at stud-bay spacing, dense-pack cellulose to 3.5 pounds per cubic foot to prevent settling, patch with matching texture, and provide a written density verification report for your permit file.

Injection Foam Wall Insulation

Signs you need it

Your walls contain obstructions like diagonal bracing or electrical panels that prevent dense-pack, or you need both insulation and air sealing in a single operation for a tight building envelope.

What it costs in Sunnyvale

Injection of slow-rise open-cell foam into enclosed wall cavities runs $4,500 to $7,500 for a typical Sunnyvale home, with higher density at rim joists and band boards.

How we do it

We inject slow-rise foam through controlled ports, monitor expansion pressure to prevent drywall bowing, trim excess after cure, and verify fill completeness with thermal imaging before patching.

What Wall Insulation Costs in Sunnyvale

Can you insulate walls without removing drywall?

Yes, drill-and-fill and injection foam both work through small interior holes that we patch and texture-match, though homes with plaster or specialty finishes may show slight variation. We assess your wall finish during the free estimate and specify the method that minimizes visual impact.

Does wall insulation meet Title 24 for ADU conversions?

Yes, when installed to the R-value and air-sealing requirements in your approved Title 24 report, which we review before specifying materials. We coordinate with your plans examiner if questions arise during inspection.

Attic Cleaning & Rodent Proofing in Sunnyvale

Sunnyvale’s mature tree canopy and mild winters support year-round rodent activity, and older homes with unsealed attic vent screens, deteriorated fascia, and gaps at utility penetrations provide easy access to insulated spaces. Attic Cleaning & Rodent Proofing is often the first step before insulation work can proceed, because new insulation installed over contaminated substrate or active entry points is wasted money.

Rodent Proofing & Exclusion

Signs you need it

You hear scratching at night, find droppings in the attic, or see chewed wiring and compressed insulation trails indicating active rodent highways.

What it costs in Sunnyvale

Comprehensive rodent exclusion with galvanized steel mesh at all entry points, vent screening, and gap sealing for a typical Sunnyvale ranch runs $1,200 to $2,400.

How we do it

We inspect with motion-activated cameras if needed, install 1/4-inch hardware cloth over vents and louvers, seal all gaps larger than 1/4 inch with rodent-resistant materials, and provide a written entry-point map with photos.

Attic Sanitizing & Decontamination

Signs you need it

Your attic has visible droppings, urine staining on insulation or framing, or a persistent organic smell that enters living spaces through recessed lights and gaps at top plates.

What it costs in Sunnyvale

HEPA vacuuming, enzymatic treatment, and fogging sanitization of a typical contaminated Sunnyvale attic runs $1,400 to $2,800 depending on contamination extent and square footage.

How we do it

We remove all contaminated insulation if present, HEPA-vacuum exposed surfaces, apply enzyme cleaner to break down organic material, fog with hospital-grade sanitizer, and provide clearance testing documentation before any new work begins.

What Attic Cleaning & Rodent Proofing Costs in Sunnyvale

How do I know rodents are gone before new insulation?

We verify exclusion with a 72-hour camera monitoring period and close all entry points with materials that show disturbance if breached; no new insulation installs until we confirm zero activity. The written scope specifies this sequence.

Will proofing keep rats out permanently?

Yes, if all entry points larger than 1/4 inch are sealed with rodent-resistant materials and maintained, though new damage from tree branches or construction can create fresh access. We document every sealed point with photos so future inspections are straightforward.

Home Energy Audit in Sunnyvale

A Home Energy Audit in Sunnyvale is the starting point for every major insulation decision, especially with Title 24 compliance required for ADU permits and the complexity of Eichler assemblies that defy standard retrofit assumptions. Our audits provide the documented baseline that lets you compare quotes apples-to-apples and verify results after work is complete.

Blower Door Test

Signs you need it

You’re considering any insulation upgrade, your home feels drafty despite closed windows, or you need a CFM50 number for a Title 24 compliance package.

What it costs in Sunnyvale

A standalone blower-door test with written report runs $350 to $550; when bundled with a full energy audit, it’s included in the comprehensive package price.

How we do it

We install a calibrated fan in an exterior door, depressurize the house to 50 Pascals, measure airflow in CFM50, and use that number to quantify your building envelope leakage and prioritize air-sealing targets.

Thermal Imaging Inspection

Signs you need it

You have uneven temperatures room-to-room, suspect missing insulation in walls, or need visual documentation of thermal bridging for a Title 24 compliance submittal.

What it costs in Sunnyvale

Thermal imaging as part of a full audit runs $450 to $750; standalone imaging for a specific issue like a suspected roof leak or insulation void runs $300 to $500.

How we do it

We scan with a FLIR camera during blower-door depressurization to exaggerate air leakage paths, mark thermal anomalies on floor plans, and provide annotated images showing surface temperatures and estimated R-value deficiencies.

What Home Energy Audit Costs in Sunnyvale

Is an audit required before insulation work?

No, but we require one for any job where we publish before-and-after blower-door numbers, because without a baseline there’s no verified performance claim. For Title 24 compliance, the audit documentation satisfies most building departments’ prescriptive path requirements.

How long does a full audit take?

Three to four hours for a typical 1,500-square-foot home, including setup, testing, interior and exterior inspection, and a preliminary walkthrough of findings. You receive the written report with photos, blower-door results, and prioritized recommendations within 48 hours.

Brands We Service in Sunnyvale

We stock and install Owens Corning, Johns Manville, Knauf, and Rockwool products from our San Francisco Bay Area warehouse, with most materials available for next-day delivery to Sunnyvale jobs. No proprietary lock-in means we specify what’s right for your assembly, not what’s in our truck. See our brands for full specifications.

Pricing for Insulation in Sunnyvale, CA

Neighborhoods We Serve in Sunnyvale

Our crews work throughout Sunnyvale with dispatch coordinated from our Bay Area office, typically arriving within scheduled windows that we confirm by text the morning of service.

• Birdland (Eichler specialist scope available)
• Lakewood
• Sunnyvale West
• Ponderosa Park
• Heritage District

Service Area - Cities Near Sunnyvale

We serve the full South Bay corridor from our Bay Area dispatch office, with regular work in Santa Clara, CA, Cupertino, CA, San Jose, CA, and Milpitas, CA. Crews carry the full material inventory and testing equipment needed for same-day diagnostics and next-day installation starts across this service area.

FAQs About Insulation in Sunnyvale