Demilec Spray Foam Insulation Nationwide

Demilec Spray Foam Insulation in San Antonio: What to Know First

Demilec spray foam insulation in San Antonio typically costs $4,200 to $9,500 for a full attic application, depending on whether you need open-cell or closed-cell foam and the square footage involved. Most Demilec jobs we handle are completed in one to two days, with closed-cell applications on the higher end because of material density and cure time. As an independent Demilec service provider, Laurel Attic Insulation San Antonio gives you a written price before any foam is sprayed, and we back the workmanship for 365 days.

Call (254) 279-0971

This page is for San Antonio homeowners who either have Demilec foam installed and suspect something is off, or who are comparing Demilec against other spray foam options before committing. If you want a straight answer on what your attic needs and what it will cost, call us at (254) 279-0971. We answer live, 24/7.

Key takeaways:

• Demilec Heatlok HFO and Sealection 500 are the two lines we see most in San Antonio attics.
• Closed-cell failures usually trace to improper mix ratios during the original install, not the foam itself aging.
• Open-cell Demilec foam absorbs humidity, which matters a lot in a San Antonio summer.
• We install, inspect, and correct Demilec work with a written guarantee and a free second visit if something fails.

How Demilec Products Fail – and How We Fix Them

Demilec makes solid foam. We install it. But when we get called out for Demilec-specific problems, they tend to follow patterns. Here’s what we actually see in San Antonio homes, including the failure modes that don’t show up on a manufacturer spec sheet.

• Heatlok HFO delamination from the roof deck. Heatlok HFO is a closed-cell foam designed for high R-value per inch, but if the original installer sprayed it over a dusty or damp deck, it can separate and leave a gap between foam and sheathing. That gap becomes a condensation trap. We cut out the affected sections, prep the surface, and respray with the right thickness. The fix is local, not a full tear-out, in most cases.
• Sealection 500 holding moisture in humid attics. Sealection 500 is an open-cell foam, which means it’s vapor-permeable. In San Antonio’s late-summer humidity, an under-ventilated attic with Sealection 500 can take on moisture that never fully dries out. That leads to musty smells and reduced thermal performance. Our fix usually involves correcting ventilation first, then evaluating whether the foam needs encapsulation or a hybrid closed-cell layer in problem areas.
• Overspray on wiring and can lights from rushed original installs. We regularly walk into Demilec jobs where foam was applied without masking electrical boxes or recessed light housings. That’s not a Demilec product failure, but it’s a Demilec job failure. We remove foam from junction boxes with care, verify connections are sound, and re-insulate around them properly.
• Off-ratio foam that stays soft or crumbly. Both Heatlok and Sealection rely on a precise mix of A-side and B-side chemicals at the gun. If the original installer’s equipment wasn’t maintained, the foam cures soft, crusty, or with a darker orange tint. That foam was bad the day it went in. We identify off-ratio zones, remove them, and respray with properly calibrated equipment.
• Rim joist applications missing the sill plate seam. In crawlspaces and basements around San Antonio, we see Demilec rim joist work where the installer stopped short of the sill plate or left voids around plumbing penetrations. Air still moves through those gaps. We remediate by cleaning the surface, filling the voids with compatible closed-cell foam, and verifying the air seal with a smoke test.

Our Demilec Spray Foam Insulation Process

Every Demilec job we run follows the same sequence. No shortcuts, no surprises at the end. Chase Whitaker and our crew have been doing this long enough that the process is second nature, but we walk you through it anyway.

1. 1
   Call and diagnostic. You describe what you’re noticing – high bills, hot rooms, a smell, visible foam pulling away. We schedule a visit and show up at a live, trackable time.
2. 2
   Attic inspection. We check the existing Demilec foam for thickness consistency, adhesion, moisture content, and off-ratio signs. We also look at ventilation and air sealing gaps that affect how the foam performs.
3. 3
   Written price. Before any work starts, we give you a written scope and dollar figure. That includes whether we’re using OEM Demilec material or a spec-matched closed-cell alternative for a local patch. You decide before we spray.
4. 4
   The repair or install. We prep surfaces, protect your home, and apply foam at the correct depth and density for the application. For closed-cell, that means around 2 inches on rooflines; for open-cell, 5.5 to 6 inches in most San Antonio attic floors.
5. 5
   Test and document. We verify the air seal, check cure quality, and take before-and-after photos. You get the digital invoice with a payment link and a written guarantee on the work.
6. 6
   365-Day Done Right Promise. If something fails within a year, we return and make it right. No charge. No argument.

What Demilec Spray Foam Insulation Costs in San Antonio

Spray foam pricing in San Antonio depends on the foam type, the square footage, and the depth you need. Here’s what we see on a typical Demilec job.

• Open-cell (Sealection 500) attic floor: $1.60 to $2.40 per board foot installed. A 1,500-square-foot attic at 5.5 inches runs $4,800 to $7,200.
• Closed-cell (Heatlok HFO) roof deck: $2.90 to $4.10 per board foot installed. A 1,500-square-foot roofline at 2 inches runs $6,500 to $9,500.
• Rim joist air sealing with closed-cell: $900 to $1,800 for a standard San Antonio crawlspace or basement perimeter.
• Garage ceiling with open-cell: $1,200 to $2,400 for a two-car garage, including cleanup.

What moves the price: access difficulty, how much old foam needs removal, and whether the surface prep requires scraping or re-sheathing. You’ll always have the exact number in writing before we start. Call (254) 279-0971 and we’ll give you an honest quote based on your attic, not a generic square-foot multiplier.

Why San Antonio Homeowners Call Laurel Attic Insulation San Antonio for Demilec Work

Most insulation companies in San Antonio won’t touch an existing Demilec install unless they put it in themselves. We take a different view. Demilec is a solid product line, and when it’s installed right, it performs for decades. When it was installed wrong, that’s a fixable problem, not a reason to gut your attic.

We carry both Demilec lines in our standard material rotation alongside Owens Corning, Rockwool, Icynene, CertainTeed, Johns Manville, Knauf, and GreenFiber. We also handle Reflectix radiant barrier for San Antonio attics where a hybrid approach makes more sense than foam alone. We match the material to the job, not to whatever is on the truck that week.

Every Demilec job we do comes with our standard stack: a written price before work starts, live technician tracking, before-and-after photo proof, a 365-Day Done Right Promise, and a free second visit if a repair fails. That’s the Relay Visibility Guarantee, and it’s built into every invoice. A comfortable attic isn’t a luxury in San Antonio – it’s just a house that works the way it should.

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