Insulation in San Jose - Same-Day Service, Done Right the First Time
We provide fast, reliable, and affordable insulation services across San Jose to keep your home safe and running. Licensed, insured, and trusted by local homeowners.
What Our Customers Are Saying
"The house had rats in the attic insulation and a smell we could not place. Walt's crew pulled all of it, sealed the gaps where they were getting in, sanitized, and put in new blown-in. He sent photos of the sealed openings so I could see it done."
"Walt came out himself, stuck his head in the attic, and told me I had about four inches where I needed fourteen. No sales pitch, just the number and what it would cost to fix it. Crew was here two days later."
"Crawl space was wet every spring. They laid the heavy liner, sealed the vents, and put a dehumidifier down there. Floors are warm and the moisture meter he left reads fine now. He still answers when I text him a reading."
At Walt's Insulation, we specialize in fast, reliable, and affordable insulation services for homeowners and businesses.
About Us
Our Simple 3-Step Process
Request Service or Call Us
Call us or send a quick message. Tell us your insulation issue and we'll schedule a convenient time.
Inspection & Free Estimate
Our technician arrives on time, inspects the problem, and gives a clear, upfront estimate with no hidden fees.
Fast Repair on the Spot
We fix the issue quickly using high-quality parts and proven techniques - working like new before we leave.
Don't let a broken insulation slow you down. Contact Walt's Insulation today and our experts will handle everything - from diagnosis to repair, quickly.
Call (408) 837-7384
Areas We Proudly Serve
Serving San Jose, CA - Our Local Coverage Area
We're based in the San Jose area and know this community well. Use the map below to see our service coverage - if you're nearby, we can almost certainly help.
Request Your Free Estimate
Prefer to talk now? Call us directly - we answer fast and dispatch even faster. No obligation, no sales pitch.
Call or Text(408) 837-7384Request A Free Quote
Insulation Service Across the San Jose Area
We Are the San Jose Team for Walt's.
Walt Brenner sticks his own head in the attic before he quotes anything, and tells you the depth you have and the depth you need in inches, not adjectives. He has talked more customers out of spray foam than into it. The written price is the price, the crew's van has his name on it, and he still answers the phone himself - including when somebody texts him a moisture reading from a crawl space he did six years ago.
Same training, same parts, same pricing practice, and the same 90-Day Done Right Promise - delivered by people who live here.
Visit Walt's →Part of the Locally Family.
Locally is a family of home-service brands held to one written standard, and Walt's is the insulation company in it. One promise stands behind every trade, in every town.
Expert Insulation Repair and Installation Services
Every job on this list is handled by trained, background-checked technicians working to one national standard, priced upfront from a free estimate.
Attic Insulation
Air-seal the attic floor first, then blow or lay insulation to the code depth for your climate zone. The depth ruler gets photographed before the hatch closes.
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Free Insulation Estimates
A technician measures what you have, tells you the depth you need in inches, and prices the whole job in writing before a bag is opened.
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Crawl Space Encapsulation & Vapor Barrier
A sealed liner up the foundation walls, taped seams, sealed vents and a dehumidifier sized for the space. Cold floors and musty air stop at the source.
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Spray Foam Insulation
Open- or closed-cell foam on rim joists, roof decks and garage ceilings. The one insulation that air-seals and insulates in a single pass.
Learn More →Materials That Hold the Line for Decades
Insulation is only as good as the material and the prep underneath it. Here is what we put into an attic, a crawl space or a wall, and what the cheap bid puts in instead.
Blown-In Insulation
Loose-fill is most of what goes into an attic. The material and the depth it is blown to decide whether the attic holds R-38 in ten years or has settled to half of it.
We blow dense, borate-treated cellulose or premium fiberglass to the full code depth with a depth marker in every bay, over an air-sealed floor. Cellulose settles less than 15% and the borate keeps insects and mold out.
A cheap bid blows the thinnest bag count that reads "insulated" from the hatch, over a floor nobody sealed. It settles a third within a few winters, and the gaps around every can light and top plate keep leaking conditioned air.
Spray Foam
Closed-cell and open-cell foam are different products for different places. Applying the wrong one, or applying it thin, is the most expensive mistake in the trade.
We use closed-cell foam where moisture and structure matter: rim joists, roof decks, crawl walls: sprayed in passes to the rated thickness, and open-cell only where its vapor-open behavior is the right call.
A cheap bid sprays one thin pass of whatever is on the truck, leaves voids behind wiring and plumbing, and puts open-cell against a roof deck where it can trap moisture in the sheathing.
Radiant Barrier
In a hot-climate attic the radiant barrier is what keeps the roof deck from cooking the insulation below it. The foil grade and how it is hung decide whether it works.
We staple perforated, tear-resistant reflective foil to the underside of the rafters with an air gap on the shiny side, so radiant heat bounces before it reaches the attic floor and moisture can still escape.
A cheap bid lays a thin foil-faced bubble wrap flat on top of the insulation, where dust kills its reflectivity in a season and it traps moisture against the batts.
Crawl Space Vapor Barrier
The liner is the crawl space job. Thickness, seam treatment and how far it climbs the wall decide whether the moisture reading drops or the liner is a puddle in two years.
We lay 12- to 20-mil reinforced polyethylene, overlap every seam by a foot and tape it, run it up the foundation wall and mechanically fasten it, then seal the vents so the space can dry.
A cheap bid rolls out 6-mil builder plastic, leaves the seams loose and stops at the footing. Ground moisture wicks around every edge and the plastic tears the first time anyone crawls on it.
Air Sealing
Insulation slows heat; only air sealing stops the air that carries it. The sealing products used on the attic floor are the difference between a comfortable house and an insulated leaky one.
We foam every top plate, plumbing and wiring penetration, fit fire-rated covers over recessed lights and gasket the attic hatch before any insulation goes down: the blower-door number proves it.
A cheap bid skips sealing entirely, or squirts a little foam where it is visible from the hatch, then buries the open can lights and gaps under new insulation where they leak for good.