Demilec Attic Insulation Nationwide

Demilec Attic Insulation: The Los Angeles Owner’s Guide

If you have Demilec spray foam in your attic and it’s underperforming, you’re in the right place. We stock Demilec-compatible materials and repair failed Demilec insulation throughout Los Angeles, with most spot repairs and re-insulation jobs running $900 – $2,400 installed depending on square footage and the condition of what’s already up there. We can usually get a crew to your house same day or next day, and we’ll give you a written price before anything starts.

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Here’s the pattern we see most often: a homeowner notices the upstairs feels hotter than it used to, or the AC is running nonstop in August, or there’s a faint chemical smell that never quite went away after the original install. Then someone pokes their head into the attic and finds gaps in the foam, shrinkage around the rafters, or sections that never fully cured. By the time we’re called, the Demilec product has usually been failing quietly for months. It’s rarely a sudden event. It’s slow, and it shows up on your energy bill first.

Laurel Attic Insulation is an independent insulation contractor. We’re not affiliated with Demilec, and we don’t pretend to be. What that means for you: we install and repair Demilec products because they’re good materials, but we also stock alternatives from Owens Corning, Rockwool, Icynene, CertainTeed, Johns Manville, Knauf, GreenFiber, and Reflectix, so we’re never stuck recommending one brand just because it’s all we carry.

Which Demilec Models This Applies To

Demilec makes open-cell and closed-cell spray foam under a few different product lines. In Los Angeles attics, the two you’re most likely to have are Sealection 500 (open-cell, half-pound foam) and Heatlok HFO or Heatlok SOYA (closed-cell, two-pound foam). The open-cell stuff is more common in vented attics where the insulation is applied directly to the attic floor or knee walls. The closed-cell products show up in unvented attics, applied to the underside of the roof deck.

The compatibility gotcha most homeowners miss: open-cell and closed-cell Demilec products are not interchangeable for the same application. Open-cell foam is air-permeable and R-3.5 to R-3.8 per inch. Closed-cell is air-impermeable and R-6.5 to R-7 per inch. If you’re patching a section and someone uses the wrong cell structure, you’ll end up with a thermal and moisture profile that doesn’t match the rest of the attic. That’s a real problem in LA’s climate, where attic temperatures can swing 60°F between afternoon and 3 a.m.

To identify what you have, look for the Demilec label or a stamp on the foam itself, typically visible near the attic hatch or on a rafter where the installer started. If there’s no label, we can identify the foam type on-site in about five minutes. For repairs, we use OEM Demilec material when the existing foam is in good enough shape to bond with it. If the original install was decades old or poorly done, we’ll often recommend removing the failed section and re-spraying with an equivalent or better product, rather than layering new foam over a bad foundation.

Signs Your Demilec Attic Insulation Is Failing

• Upstairs rooms won’t hold temperature. The AC runs constantly but the second floor still feels 8 – 10°F warmer than downstairs. That’s usually open-cell foam that has settled, shrunk, or pulled away from the framing, leaving air gaps that short-circuit the insulation.
• A lingering chemical or fishy odor, especially in warm weather. This points to incomplete curing during the original install. Off-gassing that should have finished in 24 – 48 hours can persist for years if the foam was applied too thick in one pass or mixed at the wrong temperature. It’s not a smell to ignore, especially if you have kids or anyone with respiratory issues in the house.
• Visible shrinkage or cracking around rafters and seams. Closed-cell Demilec foam can shrink slightly over time, and when that happens in a Los Angeles attic, the heat cycling from 140°F daytime temps to 60°F nights accelerates the cracking. Hairline gaps widen, and those gaps become air leaks.
• Higher energy bills with no other explanation. If your July and August SCE or LADWP bills have crept up 20 – 30% over two or three years and your equipment hasn’t changed, failed attic insulation is the most common culprit we find.
• Moisture stains on the ceiling below the attic. Closed-cell foam that’s delaminated from the roof deck lets warm, moist indoor air reach the cold underside of the roof in winter. That condensation drips onto the attic floor and eventually through your drywall.

Replacement Cost & What’s Included

For a typical Los Angeles attic, full Demilec-compatible re-insulation runs $3,500 – $7,000 for open-cell and $5,500 – $12,000 for closed-cell, depending on square footage and how much prep work the existing foam requires. Spot repairs and targeted re-sprays are usually $900 – $2,400. You can see why most people want an honest diagnosis before committing to a full re-spray, and that’s exactly what we provide.

What drives the price: the thickness needed to hit your target R-value, the accessibility of the attic (low-slope roofs and tight access points slow us down), and whether the old foam can stay put or has to be removed first. Every quote from us includes labor, material, prep, and cleanup as one line-itemed number. No separate charges that appear after the fact.

Every Demilec repair or install from Laurel Attic Insulation includes our 365-Day Done Right Promise in writing. If it’s not right within a year, we make it right. And if the repair fails, the second visit is free. No charge, no argument. That’s the Relay Visibility Guarantee our whole company runs on: a written price before work starts, live technician tracking, and before-and-after photos delivered to your phone.

DIY or Call Us?

You can absolutely check a few things yourself. Look for visible gaps between the foam and the framing. Feel for air movement near the attic hatch. Note any sections where the foam looks darker, thinner, or crunchy. That’s useful information to have when you call us.

What you shouldn’t do is attempt a DIY spray foam repair. Two-component foam requires precise temperature control, correct mixing ratios, and proper PPE including respirators. The chemicals are hazardous before they cure, and a botched patch job creates the exact off-gassing and adhesion problems we’re usually hired to fix. This is one place where the professional equipment isn’t a luxury, it’s the difference between a repair that lasts 20 years and one that fails in 18 months. If your attic is working against you, let’s just fix it, no upsell, no mystery pricing. Call us at (361) 315-4177 and we’ll get someone out to diagnose it.

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