Demilec Attic Cleaning & Rodent Proofing Nationwide | Walt’s Insulation

Demilec Attic Cleaning & Rodent Proofing in Sunnyvale: What to Know First

Demilec attic cleaning and rodent proofing in Sunnyvale typically runs $1,200 to $3,800 depending on how much damage rodents have done to your spray foam and how much cleanup the attic needs. Most jobs are completed in one to two days, and we’re usually on site within 48 hours of your call. We’re an independent Demilec service provider, not a manufacturer rep, which means we call problems like we see them and fix them without a runaround.

Call (669) 215-4805

This page is for Sunnyvale homeowners who own a home with Demilec spray foam insulation, open-cell or closed-cell, and have discovered rodents have been using it as bedding material or a highway. The one down the road, Walt’s Insulation, has been handling Demilec-heavy attics across Sunnyvale since before half the new builds south of El Camino existed. Call (669) 215-4805 and a live person answers. Always.

How Demilec Products Fail - and How We Fix Them

Demilec makes good foam. But any spray foam in an attic becomes a target once rodents get in, and different Demilec lines fail in different ways. Here’s what we actually see in Sunnyvale attics:

• Demilec Heatlok HFO (closed-cell) rodent burrowing: Rats and mice will tunnel into closed-cell foam to nest because it holds warmth and blocks light. We see this constantly in homes near Sunnyvale’s older orchard parcels, where field mice pressure is high. The foam gets chewed into divots and caves. Our fix is mechanical removal of the damaged foam back to solid material, sanitizing the area, then re-foaming with a compatible closed-cell product rather than patching over contaminated material.
• Demilec Sealection 500 (open-cell) urine saturation: Open-cell foam acts like a sponge. When rodents nest on top of or inside Sealection 500, urine soaks in and no surface cleaning fixes it. Homeowners often call about a persistent ammonia smell that gets worse on hot Sunnyvale afternoons. We cut out the saturated sections, treat the surrounding framing, and re-apply. You can’t deodorize soaked open-cell foam; you remove it. That’s a fact Demilec’s own literature won’t tell you.
• Demilec Agribalance and the bait-station blind spot: Agribalance is the soy-heavy Demilec line some Sunnyvale builders used in the 2010s. Rodents will actually eat soy-based foam in some cases, not just nest in it. No rodent proofing works if there’s still soy foam accessible, because you’re leaving food in the attic. We identify Agribalance zones, remove accessible chewed sections, and focus exclusion on entry points before any re-insulation decision gets made.
• Vapor-retarder confusion with Demilec closed-cell: In some Sunnyvale attics we see Demilec closed-cell sprayed directly to the roof deck as an unvented assembly, with the homeowner later adding storage or a ceiling fan and punching through the continuous air barrier by accident. Rodents exploit those breaks. Fixing the rodent problem correctly means understanding whether the original Demilec application was acting as the air barrier, the vapor retarder, or both. If you disturb that layer, the whole assembly can fail. We inspect before touching anything.
• Re-entry points from Demilec spray gaps around baffles: Even well-installed Demilec foam gets gaps around soffit baffles, vent pipes, and plumbing stacks. Mice need a hole the size of a dime. In Sunnyvale’s older ranch-style homes near Murphy Avenue, we routinely find multiple chases from original construction that were never sealed before foam went in. On a Demilec attic, we trace every penetration, seal with steel wool and foam, and then re-screen exterior vents. Rodent proofing fails when you skip the exterior side.

Our Demilec Attic Cleaning & Rodent Proofing Process

Here’s how a Demilec attic job runs from the first call to the final walkthrough, the way Walt Brenner has been doing it since 2000:

1. 1
   Call and live answer: You call (669) 215-4805. A real person picks up, asks about your attic, and schedules a visit. No voicemail, no call center.
2. 2
   Attic assessment: We suit up, enter the attic, and photograph everything. We’re looking for rodent entry points, damaged Demilec foam, droppings, urine stains, and whether the existing insulation needs partial or full removal.
3. 3
   Upfront quote: Before any work starts, you get a written number. We explain what’s damaged, what’s salvageable, and what your options are. Free second opinion on any written estimate, by the way.
4. 4
   Removal and sanitizing: We remove contaminated foam and insulation, vacuum droppings, fog the space with a hospital-grade decontaminant, and treat framing. This isn’t just cosmetic; rodents carry hantavirus and leptospirosis, and a dusty attic after an infestation is a genuine health hazard.
5. 5
   Exclusion and sealing: Every entry point gets closed with materials rodents can’t chew through. We seal around plumbing stacks, wire chases, and roof-wall intersections. Rodent proofing only works if the exterior is addressed with the interior.
6. 6
   Re-insulation and verification: We install compatible insulation whether that’s new Demilec foam, batts, or blown-in product and walk you through the attic afterward. Then the Done Right Promise applies: if it’s not done right, we make it right. For life.

What Demilec Attic Cleaning & Rodent Proofing Costs in Sunnyvale

Pricing depends on attic size, infestation severity, and how much Demilec foam has to come out. Here are the ranges we quote most often in Sunnyvale:

What moves the price: how many linear feet of foam got chewed, whether open-cell foam absorbed urine and needs removal, how many entry points require sealing, and whether your attic needs new insulation after the cleanup. You get an honest number before we start. No trip charge inside our county. Call (669) 215-4805 for a free estimate.

Why Sunnyvale Homeowners Call Walt’s Insulation for Demilec Work

Sunnyvale homeowners call us because we show up, we answer the phone, and we stand behind the work with the Done Right Promise. Walt Brenner’s been in attics since 2000, and his team is background-checked and uniformed. We’re not a franchise; we have a published address and a license number. If you’ve got Demilec foam that’s failed, we understand the product, and if the best fix is a different system like Reflectix radiant barrier in addition to new insulation, we’ll say so plainly. That’s how independent service providers should operate. Good insulation should be invisible – you only notice it when it’s missing. When it’s missing, or ruined by rodents, we make it right.

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