Demilec Radiant Barrier Installation: The San Francisco Owner’s Guide
Demilec radiant barrier installation in San Francisco typically runs $1.50 to $3.00 per square foot installed, with most attic jobs landing between $1,800 and $4,200 depending on square footage and access. We stock Demilec-compatible radiant barrier rolls on our trucks and can install within the same week in most San Francisco neighborhoods. Homeowners usually discover their radiant barrier has failed when summer attic temperatures climb back into the 130s or winter heating bills tick up despite adequate insulation below.
Radiant barrier isn’t insulation. It’s a reflective foil layer that bounces radiant heat back out of the attic before it soaks into your insulation and living space below. When it sags, tears, or delaminates from the rafters, it stops reflecting. In San Francisco’s coastal climate, that’s most visible during the September and October heat spikes, when west-facing attics in the Sunset and Richmond absorb direct afternoon sun.
Which Demilec Models This Applies To
Demilec produces radiant barrier under their Heatlok and Barrier line names, most commonly installed as a foil-faced component paired with their spray foam systems rather than as a standalone Demilec-branded roll product. What homeowners actually have in a Demilec-insulated San Francisco attic is often a Demilec foam application with a separately sourced foil radiant barrier stapled to the rafters. We match the existing barrier by measuring the perforation pattern and foil gauge, not by hunting for a Demilec SKU that may not exist on the roll itself.
The compatibility question that trips up San Francisco homeowners: Demilec open-cell and closed-cell foams cure at different rates, and staple penetration into cured closed-cell is the most common source of barrier detachment we see. If your barrier is pulling away from the foam, the fix isn’t a new roll. It’s re-securing with the right fastener depth and coverage for the foam type beneath. We carry both perforated and solid foil radiant barrier to match existing ventilation profiles, and we’ll tell you if an aftermarket roll performs identically to what you had, which it usually does at a better price than chasing a branded match.
Signs Your Demilec Radiant Barrier Installation Is Failing
- Attic temperature spikes on sunny days. A functioning radiant barrier keeps attic air within 10-15 degrees of outside temperature. When it climbs higher, the reflective surface has lost contact with the air gap that makes it work.
- Sagging or drooping foil between rafters. This is structural failure, usually from staples backing out of cured foam or thermal expansion cycles. The foil loses its flat reflective plane and stops bouncing heat.
- Visible tears or punctures near roof penetrations. Plumbers, electricians, and satellite installers put holes in radiant barrier without knowing it. A torn barrier still blocks some heat, but performance drops sharply once more than 10% of the surface is compromised.
- Dust buildup on the foil surface. Radiant barrier works by reflectivity, not resistance. A layer of dust cuts reflectivity measurably. In older San Francisco homes near the ocean, salt air accelerates surface dulling on exposed foil.
- Discolored or peeling foil facing. Foil delamination from its substrate is the end stage. If you can peel the reflective layer with a fingernail, it’s done.
Replacement Cost & What’s Included
Installed Demilec-compatible radiant barrier replacement in San Francisco runs $1.50 to $3.00 per square foot. A 1,200-square-foot attic typically lands between $1,800 and $3,600. The range is driven by three things: attic height and access (crawl-in attics with 3-foot clearances cost more than stand-up attics), how much of the old barrier requires removal versus overlay, and whether existing insulation needs to be pulled back to reach rafter bays.
Our written quote breaks out material, labor, and disposal separately before any work starts. That’s The Garrison Standard: you approve a number, and the invoice matches it at the end. Every install includes the 365-Day Done Right Promise in writing. If the barrier fails within a year, we return at no charge and make it right. That covers detachment, tearing from normal settling, and fastener failure.
We install radiant barrier from Demilec-compatible sources and Reflectix for retrofit applications where a branded match matters to the homeowner. Both go up the same way, and we’ll show you the spec sheet before we staple the first foot.
DIY or Call Us?
Radiant barrier installation is not a high-tension or electrical hazard, but it lives in the same attic as two things that are: recessed lighting housings and bare wiring. Radiant barrier is conductive. Stapling foil over or across live wiring is a real fire risk, and the wrong placement around can lights creates heat traps. We carry insulated staples and follow clearance codes around electrical fixtures, which is where most DIY radiant barrier jobs in San Francisco go wrong.
What you can safely do: inspect your existing barrier from the attic access point with a flashlight, note where foil is sagging or torn, and check your attic temperature on a sunny afternoon. What we recommend against: crawling through an attic with exposed wiring and a staple gun if you don’t know the clearance codes. The job itself is straightforward for a trained crew with the right fasteners. If you want to see the attic before deciding, call (559) 245-9792 and we’ll walk you through what we’d look at.
FAQs
A properly installed radiant barrier in San Francisco lasts 15 to 25 years, with coastal salt air on the west side shortening that toward the lower end if the attic vents directly to ocean air. Foil dulling from dust and salt is the main degradation path, not mechanical failure.
Small tears under 6 inches can be patched with foil tape and restored to near-full performance, but sagging or detached sections larger than a few square feet usually need re-stapling across the whole bay to sit flat again. We’ll tell you honestly which one your attic needs before quoting either path. Call (559) 245-9792 for a straight answer.
Most San Francisco radiant barrier replacements finish in one day, with larger or multi-level attics taking two. We schedule a specific arrival window, not a half-day range, and the crew shows up uniformed and background-checked.
We stock Demilec-compatible perforated and solid radiant barrier rolls plus Reflectix for retrofit jobs, so most replacements start and finish the same day we arrive. If your attic needs a specific size we don’t have, we source it and return inside the week.
If your Demilec radiant barrier is sagging, torn, or just not keeping the attic cool anymore, call (559) 245-9792. We’ll give you a written price before work starts, install it right, and stand behind it for a full year. Good insulation doesn’t announce itself. You just stop noticing the cold.
Written by Bryce Holloway, Owner, Alden Insulation San Francisco at Alden Insulation San Francisco, serving San Francisco and nearby areas.