Demilec Radiant Barrier Installation: The Boerne Owner’s Guide
Demilec radiant barrier installation in Boerne typically runs $1,800-$3,400 for a standard 2,000-square-foot attic, and we stock Demilec-compatible materials for same-day starts on most jobs. Most homeowners figure out something’s wrong when their upstairs rooms won’t cool below 78 degrees even after the AC runs all afternoon, or when their July electric bill jumps $80-$120 from the previous year. We see this pattern constantly in Boerne homes built between 2005 and 2018, where original radiant barrier foil has degraded or was never paired with proper air sealing to begin with.
Which Demilec Models This Applies To
Demilec doesn’t sell a standalone “radiant barrier” product line under that exact name. What Boerne homeowners usually mean is the reflective component installed alongside Demilec spray foam systems, typically Demilec Heatlok HFO Pro or Demilec Sealection 500 jobs where a radiant foil layer was added to the roof deck or attic rafters as a hybrid assembly. To identify what you have, check your original invoice for terms like “reflective roof coating,” “radiant foil overlay,” or “hybrid radiant system.” The critical compatibility gotcha: Demilec open-cell foam requires a vapor-permeable radiant barrier, while closed-cell applications can handle standard foil-backed products. Mix those up and you trap moisture against the foam.
We source OEM-grade Demilec-compatible materials through our regular suppliers, but we also install quality aftermarket equivalents from Reflectix when the assembly allows. The aftermarket route saves roughly 15-20% on material cost without sacrificing performance, provided the perm rating matches the original spec. We keep both on the truck. Topside Attic Insulation Boerne is an independent service provider with no affiliation to Demilec.
Signs Your Demilec Radiant Barrier Installation Is Failing
- Hot second-floor ceilings by 3 p.m. The radiant barrier’s reflective surface has oxidized or accumulated dust to the point where emissivity has risen above 0.10. Once that happens, the foil is basically painted plywood, thermally speaking.
- AC runs continuously from noon to sunset. Your cooling load has shifted later into the day because roof deck temperatures aren’t being rejected back out. In Boerne, unshaded asphalt shingle roofs hit 160°F in August; without a functioning barrier, that heat radiates straight through.
- Visible tears, sagging, or gaps in the foil. These create thermal bypasses. A 5% gap area can reduce overall radiant barrier effectiveness by 40% or more, especially common in older Boerne homes near the Cibolo Nature Center where roof-deck movement from our clay soils works fasteners loose.
- Moisture staining on the attic-side drywall. This usually means the original installer used the wrong perm rating for the Demilec foam type underneath. Open-cell Demilec with an impermeable foil barrier traps interior moisture against cold roof sheathing in winter.
- Your July 2024 electric bill was your highest ever despite no rate increase. CPS Energy rates held steady for most Boerne residents last year; if your usage spiked 20-30% over July 2023, envelope performance is the likely culprit, not the utility.
Replacement Cost & What’s Included
Most Demilec radiant barrier replacements in Boerne run between $1,800 and $3,400 installed. The lower end covers straightforward re-foil of intact roof decking in a 1,200-1,800 sq ft attic with good access. The upper end reflects larger homes, steep pitches above 8/12, or jobs where we need to remove degraded material and address the air-sealing work that should have preceded the original installation.
Every quote breaks down material, labor, and any necessary remediation line by line. Under Haven Standard Clause 1, you get that written price before anyone touches a tool. The work includes removal of failed barrier material, installation of replacement foil or reflective sheathing, and on applicable jobs, before-and-after blower-door readings so you see the actual air-leakage change. Our 365-Day Done Right Promise covers the installation. We don’t warranty the Demilec foam itself, that’s between you and your original applicator, but we document its condition with photos before we start.
DIY or Call Us?
There’s no high-tension spring or electrical hazard here, but attic work in Boerne summer is its own safety issue. Roof deck temperatures reach 140-160°F by midday. Heat exhaustion arrives faster than most people expect, especially on pitches above 6/12 where you’re working against gravity while overheating.
What you can safely check from the hatch with a flashlight: whether the foil is intact, whether it’s sagging or torn, and whether you see any moisture staining on the sheathing. What goes wrong with DIY radiant barrier work: installing the wrong perm rating for your existing foam type, leaving gaps at hips and valleys that defeat the whole assembly, and compressing insulation underneath while you’re moving around. We’ve been called in to fix homeowner jobs where the reflective surface ended up facing the wrong direction, which is an expensive way to learn that emissivity works one way.
Seal the envelope first. Then fill it. If your attic floor leaks like a sieve, new radiant barrier foil is performance theater. We run the blower-door test to prove the difference.
FAQs
A properly installed radiant barrier in Boerne lasts 15-25 years, but dust accumulation and our Hill Country wind-driven debris can cut that to 10-12 years if the attic isn’t sealed well. Call (830) 529-7780 and we’ll check your current condition for free.
Small tears can be patched with matching foil tape, but widespread oxidation or sagging means replacement. Patching over degraded material is usually false economy, the underlying surface has already lost its reflective properties. We can assess which path makes sense for your specific assembly.
Most residential jobs in Boerne finish in one day, occasionally stretching to two for larger homes or when we find unsealed top plates that need addressing first. You’ll get a written schedule with your written price before work starts.
Yes. We keep Demilec-compatible reflective materials and Reflectix equivalents on our trucks, which is why most Boerne jobs start same-day or next-day once you approve the written scope. Call (830) 529-7780 to confirm current stock for your specific assembly type.
Ready to stop your upstairs from baking every afternoon? Call (830) 529-7780 for a free estimate. We’ll run a blower-door test, show you the numbers in pascals on paper, and give you a written price before any work starts. Every job closes with a Documented Photo Record and, where applicable, before-and-after pressurization readings so you can verify what changed.
Written by Wes Okafor, Owner, Topside Attic Insulation Boerne at Topside Attic Insulation Boerne, serving Boerne and nearby areas.