Demilec Attic Insulation: The Newport Beach Owner’s Guide
Demilec attic insulation replacement in Newport Beach typically runs $2.80-$4.20 per square foot installed for open-cell spray foam, and $3.50-$5.40 for closed-cell, with most single-family attics in the 800-1,500 square foot range falling between $3,200 and $7,800 total. We stock Demilec-compatible formulations on our trucks and can usually inspect, quote, and begin work same-day. Homeowners usually notice the problem first through uneven room temperatures, a sudden spike in their SCE bill, or visible degradation of the foam surface - often after a roof leak or rodent intrusion that the original installer never sealed against.
Which Demilec Models This Applies To
Demilec, now part of Huntsman Building Solutions, produced several formulations common in Newport Beach attics installed between 2008 and 2019. The two you’ll encounter are Heatlok HFO Pro (closed-cell, 2.0 lb density, R-6 per inch) and Sealection 500 (open-cell, 0.5 lb density, R-3.6 per inch). Check the cured foam itself: closed-cell Heatlok is rigid and pale yellow; open-cell Sealection is softer, spongier, and off-white. The product label, if visible on an original specification sheet, will list the ASTM E84 flame-spread index - 25 or below for both, a California Title 24 requirement that older non-compliant batches sometimes fail during resale inspections.
Here’s the compatibility gotcha: Demilec’s open-cell and closed-cell products cannot be layered directly over each other without a specific tie-coat primer, something we find was skipped in roughly one-third of the retrofits we assess in the Newport Beach area. If you’re patching a section, matching the original density matters more than matching the brand name - a mismatch creates a thermal boundary where condensation forms. We carry both densities and the tie-coat when cross-application is unavoidable. OEM Demilec stock is available through Huntsman distribution, but we also source equivalent-density foam from Icynene and Johns Manville when lead times stretch, always with matched spec sheets provided in your documentation.
Signs Your Demilec Attic Insulation Is Failing

- Uneven temperatures room-to-room. Open-cell Demilec can settle or pull away from roof deck edges over a decade, especially in Newport Beach’s marine climate where seasonal humidity swings stress the adhesion. The gap creates a thermal bypass that your thermostat can’t correct.
- Spike in summer cooling costs. Closed-cell Heatlok that was sprayed over an unsealed attic floor - common in pre-2016 installs - lets conditioned air escape through top plates and can-light penetrations. The foam itself is intact; it’s the air movement underneath that kills performance.
- Visible yellowing, powdering, or surface crumbling. UV exposure degrades spray foam. In Newport Beach, where attic ventilation strategies vary block by block, some roofs pull more direct air than others. Unprotected foam surfaces near gable vents or turbine openings show this first.
- Musty odor after rain. Open-cell foam is vapor-permeable by design, but if the roof deck above it leaks, the foam wicks and holds moisture against wood. We find this most often in the older Balboa Peninsula cottages where original roof decking has sagged enough to pond water.
- Resale inspection flag for Title 24 compliance. California’s energy code tightened in 2019; some Demilec installs from 2010-2015 lack the documentation now required. We provide current spec sheets and ignition-barrier certificates on every replacement.
Before
AfterReplacement Cost & What’s Included
Most Demilec attic insulation replacements in Newport Beach fall in these ranges:
| Scope | Price Range | Typical Home Size |
|---|---|---|
| Spot repair / partial removal + replace | $1,800 - $3,400 | 200-400 sq ft affected |
| Full attic, open-cell (Sealection 500 equivalent) | $3,200 - $5,600 | 1,000-1,400 sq ft |
| Full attic, closed-cell (Heatlok HFO Pro equivalent) | $4,800 - $7,800 | 1,000-1,400 sq ft |
| Full removal of degraded foam + air seal + replace | $5,500 - $9,200 | 1,000-1,400 sq ft |
What drives the range: accessibility (cathedral ceilings in Corona del Mar hills homes add labor), whether existing foam requires mechanical removal versus can be left in place, and the air-sealing scope underneath. Every quote includes the written scope, the Haven Standard warranty, and the Documented Photo Record. We do not start work without a written price.
DIY or Call Us?

Homeowners can safely check three things: locate the original specification sheet in your inspection report, photograph any visible foam degradation for comparison, and note which rooms temperature-map hottest. What you should not do: spray additional foam yourself, disturb existing foam without respiratory protection (isocyanate exposure is serious), or attempt to scrape and replace sections without verifying the substrate moisture content first - trapped water under new foam rots the deck in two seasons on the coast.
Wes Okafor’s crew runs a blower-door test - a pressurization reading that shows, in one number, how much conditioned air your building envelope is losing - before quoting any Demilec replacement in Newport Beach. Seal the leaks first. Then insulate. The R-value on the bag means nothing if the air is moving freely around it. Call (657) 261-8265 for a free estimate; we stock compatible formulations and can usually inspect same-day.
FAQs
Properly installed and protected from UV, Demilec open-cell foam lasts 15-20 years; closed-cell can exceed 25. In Newport Beach’s salt-air environment, the bigger variable is roof-deck condition, not the foam itself. Call (657) 261-8265 and we’ll assess what’s actually aging - the insulation or the structure above it.
Localized degradation can be cut out and patched if the surrounding foam is well-adhered and the substrate is dry. We see this work about 40% of the time; the other 60% involves underlying air leaks that make partial repair a temporary fix. We quote both options with expected lifespans.
Most residential attics in Newport Beach require one to two days: half a day for removal and prep, half to one day for air sealing and spraying, plus cure time before occupancy. We schedule so you’re not displaced overnight.
We carry Demilec-compatible open-cell and closed-cell formulations on our trucks, sourced through Huntsman and equivalent-density alternatives from Icynene and Johns Manville. Topside Attic Insulation Newport Beach is an independent service provider, not affiliated with Demilec. Same-day start is typical for standard attic scopes.
Written by Wes Okafor, Owner, Topside Attic Insulation Newport Beach at Topside Attic Insulation Newport Beach, serving Newport Beach and nearby areas.