Demilec Radiant Barrier Installation Nationwide

Demilec Radiant Barrier Installation: The Long Beach Owner’s Guide

We install Demilec radiant barrier in Long Beach attics for $1.85 to $3.10 per square foot, and most homes fall between $2,200 and $4,800 total. We stock Demilec-compatible foil radiant barrier rolls on our trucks, so a typical single-story attic in Long Beach is usually done in a single visit, often same-day when you call before noon. Most homeowners discover their radiant barrier is failing when they walk into an upstairs bedroom in August and it feels ten degrees hotter than the hallway, or when they climb into the attic for holiday decorations and see foil sagging between the rafters instead of sitting taught.

Call (562) 471-3972

We’re Thistledown Insulation Long Beach, an independent installer. We are not affiliated with Demilec, but we install and stock their product line alongside our full insulation menu. Neil Barron and our crew have been in Long Beach attics long enough to know that a radiant barrier only works if it is installed with the right air gap, the right stapling pattern, and the right understanding of how coastal humidity behaves up there.

Which Demilec Models This Applies To

Demilec makes radiant barrier sheathing and foil products under a few distinct names, and the compatibility question comes down to which one you already have. The two most common in Long Beach are the perforated foil designed for attic-rafter installation and the laminated sheathing boards used in new construction near the Port and in retrofit jobs across Bixby Knolls. The perforated foil gets stapled to the underside of rafters, and it requires a half-inch to three-quarter-inch air gap facing the attic space to do its job. The laminated sheathing installs as a structural panel and does not need that gap.

Here is the compatibility gotcha we see regularly: the perforated foil and the laminated sheathing do not substitute for one another. If your 1980s tract home in Los Altos has perforated foil stapled over the rafters and you order laminated sheathing thinking it is an upgrade, you will be redoing the job. Check the printing on the foil edge before you buy anything. If you cannot read it, measure the perforation spacing. Demilec perforated foil has holes roughly every half inch. That is how we identify it on site.

We recommend OEM Demilec product for any home where the rest of the attic already carries Demilec materials. For homes where the radiant barrier is the only Demilec product up there, a quality aftermarket perforated foil from Reflectix does the same job for slightly less. Both sit on our trucks. We will tell you which one makes sense for your house and write the exact price before we open a single box.

Signs Your Demilec Radiant Barrier Installation Is Failing

• Sagging foil between rafters. Staples pull loose over time, especially in coastal air, and the foil loses its taught surface. Once it sags, the reflective angle changes and it stops bouncing heat back out of the attic.
• Tears along the staple line. Long Beach gets real temperature swings from June gloom mornings to 85-degree afternoons. Foil expands and contracts, and after ten or twelve years that stress tears the foil right at the staple line. The tear becomes a heat leak.
• Dust coating the reflective face. Reflective foil only works if the surface stays shiny. Attic dust settles on anything horizontal, and a dull, grey film cuts performance measurably. We can clean and re-staple in most of these cases cheaper than a full replacement.
• Upstairs rooms warmer despite working A/C. If your bedrooms are reliably five to ten degrees warmer than downstairs from 3 p.m. onward, the radiant barrier is doing less than it should. You feel it first in the rooms closest to the attic hatch.
• Visible condensation on the foil. In a coastal climate like Long Beach, a radiant barrier without the proper air gap can trap moisture against the foil. We have seen this near Belmont Shore homes, where wet air creeps into the attic from bathroom vents that terminate too close. Wet foil delaminates quickly.

Replacement Cost & What’s Included

Radiant barrier installation in Long Beach runs $1.85 to $3.10 per square foot installed, depending on roof pitch, attic access, and whether we are removing failing foil first. A 1,200-square-foot attic in the neighborhoods around El Dorado Park typically falls between $2,200 and $3,700. A tight attic with a low roof slope near Alamitos Beach might land closer to $4,000 because the crew works kneeling the whole time.

That number includes removal and disposal of the old foil, new Demilec or Reflectix perforated foil, staples rated for attic heat, and cleanup. You will see the itemized labor and material split in writing before we start, because that is how Neil runs every job. “Know what you’re getting before we touch a wall.” We back the installation with our 365-Day Done Right Promise. If the foil sags or tears in the first year, we come back and redo it. No debate.

DIY or Call Us?

Radiant barrier installation is one of the safer attic jobs. It is foil, not high-tension springs or electrical work. That said, the wrong direction of the foil, staple spacing that is too wide, or installing it flat against the roof deck instead of leaving an air gap will produce a product that does nothing except look shiny. You also need to be realistic about working in a Long Beach attic in summer. It is 120 degrees up there in July, and heat exhaustion on a ladder is a real risk.

What you can safely check yourself: look for the foil’s printing to read the brand and perforation type, measure the gap between foil and roof deck, and check for tears around the edges. What we do not recommend is spending four hours in a 120-degree attic wrestling a 100-foot roll on a Saturday. We do this all the time, we bring the right staples, we wear shoe covers into the house, and we leave a photo of the clean-up before we go. Call (562) 471-3972 and we will have someone out to look at your attic and give you a written number.

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