Demilec Insulation Removal in San Francisco: What to Know First
Demilec insulation removal in San Francisco typically runs between $3,100 and $7,800 depending on attic square footage, foam type, and how thoroughly the original install bonded to the framing. Most Demilec jobs we handle are completed in one to two days, with same-week scheduling available for homeowners who call (559) 245-9792. We’re an independent Demilec service provider, not a factory-authorized shop, which means we tell you straight what the foam is doing and what it’ll take to get it out. This page is for San Francisco homeowners with Demilec open-cell or closed-cell spray foam in attics, rim joists, or crawl spaces who need it removed because of moisture problems, poor curing, failed adhesion, or a renovation that’s exposing old foam. Bryce Holloway and our crew have pulled failing foam out of enough Sunset District Victorians and Richmond District Edwardians to know exactly what we’re walking into before the first ladder goes up.
How Demilec Products Fail – and How We Fix Them
- Heatlok HFO shrinkage and delamination. Heatlok HFO is Demilec’s closed-cell line, and in San Francisco’s cool, damp climate we see it pull away from sheathing when it was sprayed too cold or too thick in a single pass. The foam cures with internal stress, then shrinks over two to three seasons. You’ll see gaps at the top plates and around roof decking. Fix: full mechanical removal with oscillating scrapers and wire brushing back to clean wood, then either re-insulation with an open-cell product or air sealing and batt, depending on the cavity depth.
- Sealection 500 open-cell holding fog moisture. Sealection 500 is a low-density open-cell foam that’s common in San Francisco attic rooflines. The problem here is the marine layer. Fog pushes under ridge vents and open-cell foam is vapor-permeable, so it absorbs moisture and holds it against the roof deck. We see this in the Sunset and Outer Richmond more than anywhere else in the city. The foam feels damp to the touch and the decking starts to gray. Fix: removal down to the sheathing, a moisture assessment, and if the decking is sound, re-foaming with closed-cell or switching to a ventilated insulation strategy.
- Demilec APX off-ratio spray leaving sticky or friable foam. APX is Demilec’s mid-range closed-cell product, and when the A and B sides drift off ratio, the foam never fully cures. It stays tacky or crumbles when you touch it. That’s a chemical problem, not a weathering problem, and it never corrects itself. We’ve seen this in homes sprayed between 2018 and 2021 by contractors running worn proportioning pumps. Fix: complete removal of the off-ratio foam. You can’t spot-fix this one; the uncured material off-gasses and keeps degrading.
- B-Side separation in rim joist applications. In San Francisco basements and crawl spaces, Demilec closed-cell foam sprayed on rim joists sometimes separates from the concrete or the band joist because the substrate was never properly dried or primed. The foam looks fine from two feet away, but pull back the face and it’s hanging free. That void is where conditioned air escapes. Fix: cut out the affected sections, remediate moisture at the source, and reapply with proper substrate prep. We match the re-insulation to the original R-value spec when possible.
- Re-roofing exposure forcing removal. When a San Francisco homeowner gets a new roof on an older home, any Demilec foam against the underside of the roof deck usually has to come out so the decking can be inspected and replaced where needed. If the roofer finds rot under foam, that’s a repair that started inside the attic. We coordinate directly with the roofing crew so the deck is clear on their schedule, not ours.
Our Demilec Insulation Removal Process
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Call and assessment. You call (559) 245-9792 and we ask the questions that matter: What year was the foam sprayed? Which Demilec product is on the invoice? Is the attic vented or sealed? Where are you seeing the problem? That tells us whether we’re doing a surgical removal or a full gut.
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Site walk and written price. Bryce or a senior tech comes out, gets into the attic, probes the foam in three or four spots, checks decking moisture, and photographs everything. You get a written price before any tool leaves the truck. That number is the number on the invoice.
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Containment setup. We seal off the work zone, run negative air, and lay floor protection. Demilec removal generates fine foam dust and we treat it accordingly. No dust in the living space, period.
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Mechanical removal. We scrape, cut, and pull foam back to clean substrate using hand tools and oscillating blades. No heat guns, no open flame, no chemicals that’ll gas off into your house. Demilec foam is mechanically bonded and it comes out mechanically.
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Substrate inspection and prep. Once the foam is out, we check the decking or framing for moisture damage, rot, or mold. If we find something structural, we flag it and give you a straight assessment. If the wood is sound, we prep it for whatever’s going back in.
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Re-insulation and written guarantee. We install the replacement insulation (air sealing, batt, blown-in, or new foam) and you get the 365-Day Done Right Promise in writing. If the work fails within a year, we’re back at no charge.
What Demilec Insulation Removal Costs in San Francisco
Most Demilec removal jobs in San Francisco fall into three pricing bands. A partial removal (failed section of rim joist or a single slope of roofline) runs $3,100 to $4,500. A full attic roofline removal on a typical 1,200 to 1,600 square foot San Francisco home runs $4,800 to $6,500. A full attic with crawling-height access, heavy cross-bracing, or extensive moisture damage runs $6,500 to $8,500. What moves the price: attic access (scuttle hole versus stairs), foam thickness, whether the foam is open-cell or closed-cell, how much decking needs replacing underneath, and whether we’re coordinating with a roofing crew on a deadline. Every quote includes disposal, containment, and the written guarantee. Call (559) 245-9792 for a free estimate. We’ll give you the number in writing before we start.
Why San Francisco Homeowners Call Alden Insulation San Francisco for Demilec Work
We’re an independently owned and operated shop, part of the Garrison Partners family since 2002, and every job we take runs under The Garrison Standard: written prices, written guarantees, and a background-checked, uniformed crew that arrives inside the window we promised. We install and remove insulation from eight brands you can research on your own, including Owens Corning, Johns Manville, Knauf, Rockwool, CertainTeed, Icynene, Demilec, and GreenFiber. If a Demilec product isn’t the right call for what your attic actually needs, we’ll tell you that before we sell you anything. And if you’re looking at Reflectix for a radiant barrier application, we work with that too. Good insulation doesn’t announce itself. You just stop noticing the cold.
FAQs
Demilec’s manufacturer warranty covers foam that fails due to manufacturing defects, but it generally does not cover removal labor, and claims require documentation that most San Francisco homeowners don’t have on file. As an independent Demilec service provider, we don’t process warranty claims for the manufacturer, but we’ll give you a straight assessment of what failed and why, and the written documentation you’d need to pursue a claim yourself. Call (559) 245-9792 if you want us to take a look before you file.
Yes, when the foam was applied to a clean, dry substrate and cured properly. Our removal is mechanical, not chemical, and we test adhesion in several spots to determine whether the foam will release cleanly or whether it’s bonded hard enough to pull wood fibers with it. In some San Francisco homes, especially older Victorians with softer redwood decking, the foam bonds harder than the wood’s own structural integrity, and some decking replacement is unavoidable. We’ll tell you that risk before we start, not after.
If the foam is dry, adhered, and doing its job, removal is usually unnecessary. If it’s wet, off-ratio, or blocking access to damaged decking, leaving it costs more in the long run. Wet foam against a roof deck in San Francisco’s climate will rot the decking faster than an uninsulated attic dries it out. We’ll give you a price for removal and a price for working around it, and we’ll tell you which one we’d do on our own house. Call (559) 245-9792 for an exact quote.
Most Demilec removal jobs are completed in one to two working days. Partial removals, like a failed rim joist section or a single roofline slope, are often done in a day. A full attic roof deck removal with disposal and substrate inspection takes two days. We schedule by appointment and we show up inside the window we give you.
We remove Demilec foam in attics, crawl spaces, and rim joist cavities. Rim joist foam in San Francisco basements is often the most water-damaged foam in the house because it’s sprayed against concrete or foundation walls that wick ground moisture. We handle the removal, the moisture source, and the re-insulation as one job.
Written by Bryce Holloway, Owner, Alden Insulation San Francisco at Alden Insulation San Francisco, serving San Francisco and nearby areas.