Demilec Attic Insulation Nationwide

Demilec Attic Insulation: The Los Angeles Owner’s Guide

We stock, install, and repair Demilec-compatible attic insulation across Los Angeles, with most jobs running $2,100 to $5,800 installed depending on attic size and the specific Demilec product involved. Same-day and next-day appointments are available for most neighborhoods, and every quote is written before any work starts. Most Los Angeles homeowners call us after noticing a hot second floor, a spike in the electric bill during August, or insulation that’s clearly settled and compressed in an attic that used to stay comfortable. We’re an independent Los Angeles insulation contractor, not a Demilec dealer or affiliate, so our loyalty is to the homeowner and the right fix, not a single brand’s inventory.

Call (213) 376-3824

The Demilec products we work with most often in Los Angeles attics are open-cell spray foam (typically Heatlok HFO Pro) and closed-cell spray foam (typically Sealection 500). Both show up in LA homes built or retrofitted in the last 15 to 20 years. When the foam was installed correctly, it should outlast the roof. When it wasn’t, you’ll know within a few summers. Tell me what’s in your attic and I’ll tell you exactly what it needs – no guesswork, no upsell. Call (213) 376-3824 and we’ll set up an attic inspection.

Which Demilec Models This Applies To

Demilec manufactures spray polyurethane foam (SPF) under two main lines that show up in Los Angeles attics. Heatlok HFO Pro is a closed-cell foam, typically applied at 2 to 3 inches on the attic floor or roofline. Sealection 500 is an open-cell foam, most often applied at 5 to 6 inches in vented attics or 3 to 4 inches against the roofline in unvented assemblies. Both are two-component systems: an “A” side (isocyanate) and a “B” side (polyol resin) that mix at the spray gun.

Here’s the compatibility gotcha most Los Angeles homeowners run into: Demilec foam is not a drop-in patch product. You cannot buy a can of Demilec off the shelf and fill a gap the way you’d patch drywall. Compatibility depends on the existing foam’s density, age, and condition, plus the attic’s ventilation setup. If the attic has unvented roofline foam, adding vented attic floor insulation is a different conversation entirely, and that’s where we see installers go wrong. The specs on the foam drums, the install date, and whether the foam is open-cell or closed-cell determine what we can and can’t do. If you still have the original work order or can read a drum label in the attic, that saves us a site visit’s worth of detective work. If you don’t, we’ll identify it in about 15 minutes during an inspection.

For replacement material, we match the existing Demilec foam with the correct Demilec product or a specification-equivalent from one of the eight brands we keep on hand: Owens Corning, Johns Manville, Knauf, Rockwool, CertainTeed, Icynene, Demilec, and GreenFiber. In some homes, we also install Reflectix radiant barrier alongside attic insulation to knock back the heat load that Los Angeles roofline foam alone doesn’t address. We use what the attic actually needs, not what’s easiest to stock.

Signs Your Demilec Attic Insulation Is Failing

• Second floor runs 8 to 12 degrees hotter than the first floor. This is the most common call in Los Angeles. Closed-cell Demilec that’s pulled away from the roofline or floor framing creates thermal bypasses. The foam can look intact from the attic hatch while heat pours through the gaps behind it.
• Your July and August electric bill jumped 30% or more year over year. Demilec foam doesn’t “wear out” predictably, but when it fails, the air conditioning load climbs fast. If your bill changed before your habits did, the attic is the first place to look.
• Visible shrinking, cracking, or separation at foam edges. Open-cell Demilec can shrink slightly as it cures, especially when installed during Los Angeles winter months when attic temperatures were near the product’s low-end application window. Gaps of even half an inch at framing members cut into the foam’s air-sealing performance.
• Dust, soot, or pest droppings on top of the insulation. Rodents and pests tunnel through open-cell foam and nest in it. This is an LA reality in older homes: rats in the attic will carve runs through Demilec foam in a season. The foam doesn’t fail on its own; it gets destroyed from the outside.
• Musty smell or visible staining around can lights or ceiling penetrations. When Demilec foam at the roofline fails, warm attic air meets air-conditioned ceiling air, creating condensation. That dampness shows up as ceiling stains around light fixtures and vents. This is a moisture problem caused by an insulation problem, and it won’t dry out on its own.

Replacement Cost & What’s Included

In Los Angeles, Demilec attic insulation repair or replacement runs these ranges:

Every price includes removal and disposal of failed material where needed, prep of the attic, installation, and a written 365-Day Done Right Promise covering labor and materials for a full year. If the repair fails within that year, the second visit is free. We write the price before work starts and it doesn’t move. The range depends on attic access (crawlspace attics cost more in labor), how much failed foam must be removed, and whether we’re matching an existing Demilec install or converting to a different system entirely. Garrett will explain the number line by line during the estimate.

DIY or Call Us?

Honest answer: Demilec attic insulation is not a homeowner repair job. The foam is a two-part chemical system applied with heated, pressurized equipment. The closed-cell product in particular gives off fumes during application and requires respirators, protective suits, and ventilation protocols you don’t want to run in a 120-degree Los Angeles attic. Even the inspection is worth having us do, because a compressed-looking patch of open-cell foam might be doing its job fine while the real failure is happening at the roofline where you can’t see it from the hatch.

What you can safely do is pull down the attic ladder, take photos with your phone, and check the hatch for obvious gaps, stains, or pest activity. That gives us a starting point. But the actual repair, the removal, and the reapplication all belong to a trained crew wearing the right gear. Our technicians arrive in marked uniforms with photo ID badges, and you get their name and photo before the visit, so you know exactly who’s showing up. Call (213) 376-3824 and we’ll schedule the inspection.

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