Demilec Crawl Space Encapsulation & Vapor Barrier in Burbank: What to Know First
Demilec crawl space encapsulation and vapor barrier work in Burbank typically runs $2,800-$6,500 depending on crawl space square footage and whether the existing Demilec HFO spray foam or SEALECTION 500 barrier has degraded from our local clay-heavy soil moisture. Most jobs we can scope and price same-day, with work starting within 48 hours of written approval. As an independent Demilec service provider, we don’t represent the manufacturer, but we stock the full Demilec accessory line and have handled more failed vapor barriers in Burbank’s crawl spaces than any other insulation contractor in our service area.
This page is for homeowners who’ve found soft spots in their Demilec vapor barrier, noticed musty odors rising through floor registers, or pulled back insulation to find the white SEALECTION coating has turned chalky or delaminated from the concrete stem wall. If that’s your situation, call (213) 816-1699. A live person answers, and we’ll get a technician out to your Burbank property with a written price before any work starts.
How Demilec Products Fail - and How We Fix Them
- SEALECTION 500 delamination at the stem wall in Burbank’s clay soils. The hydrophilic primer that bonds SEALECTION 500 to poured concrete breaks down when seasonal moisture wicks upward through Burbank’s expansive clay subsoil, particularly in the hillside areas near Verdugo Mountains. We see this most in homes built 2008-2016 where the original installer skipped the moisture-cured polyurethane anchor strip. Our fix: mechanical fastening with Demilec-compatible termination bars, not just re-priming, because the substrate itself has become compromised.
- HFO Pro insulation sagging in vented crawl spaces. Demilec’s HFO closed-cell spray foam gains R-value per inch but adds weight. In Burbank’s older ranch homes with 24-inch on-center joist spacing, gravity wins over time, especially where the original pass was too thin to achieve the labeled density. We remove the failed sections, re-strap with galvanized wire and proper spacers, then reapply to Demilec’s specified 2-inch minimum pass thickness. The R-value is what the label says. The performance is what the blower-door test says. We care about the second number.
- Heatlok XT thermal drift in seasonal moisture cycles. Heatlok XT’s polyisocyanurate core can lose up to 15% of its R-value when subjected to repeated wet-dry cycles, which is exactly what happens in Burbank crawl spaces where summer irrigation oversaturation meets winter drying. We diagnose this with a calibrated moisture probe, not visual inspection alone. When we find Heatlok XT with moisture content above 19%, we replace it with a Demilec vapor barrier system rated for hydrostatic pressure, not just vapor diffusion.
- Demilec air barrier gaps at plumbing penetrations. The factory-cut sleeves in Demilec vapor barrier membranes rarely match the actual pipe layout in Burbank’s modified post-war homes, especially in the Magnolia Park neighborhood where homeowners have added bathroom vents and recirculation lines. We field-fabricate Demilec-compatible boot seals with EPDM collars and stainless-steel draw bands, then pressure-test the seal with a smoke pencil. This takes longer than a tape patch. It also doesn’t fail in three years.
- AgriThane 7520 degradation from soil-gas exposure. AgriThane 7520 was marketed for agricultural and light commercial use but appears in some Burbank residential crawl spaces from the 2010-2014 retrofit boom. The aromatic isocyanate formulation breaks down when exposed to methane and radon soil gases common in the Verdugo fault zone. We replace AgriThane with Demilec’s current HFO formulation or, for severe soil-gas conditions, a multi-layer system with a dedicated sub-slab depressurization port integrated into the vapor barrier.
Our Demilec Crawl Space Encapsulation & Vapor Barrier Process

- 1
Moisture mapping and material identification. We probe the existing Demilec product with a Delmhorst moisture meter, photograph the label codes, and document the installation pattern. You get these photos before we leave the site.
- 2
Blower-door and crawl space pressure diagnostics. We run a blower-door test to establish the home’s baseline ACH50, then isolate the crawl space with a temporary seal to measure pressure differential. This tells us whether the crawl space is acting as a return plenum or a pressure sink.
- 3
Written scope and price, no exceptions. Under Haven Standard Clause 1: flat price, written scope, written warranty before anyone lifts a tool. We specify OEM Demilec materials versus quality aftermarket alternatives where the original line has been discontinued.
- 4
Air sealing first, then barrier installation. We seal all penetrations with Demilec-compatible sealants, install mechanical termination at the stem wall, then lay the vapor barrier with welded seams, not tape. For HFO spray foam jobs, we achieve the full pass thickness in a single lift where possible, or timed multiple passes per Demilec’s cold-weather protocol.
- 5
Post-installation verification. We run a second blower-door test, provide the before-and-after CFM50 readings, and deliver a Documented Photo Record showing seam welds, termination details, and depth measurements. The 365-Day Done Right Promise applies from this date.
Before
AfterWhat Demilec Crawl Space Encapsulation & Vapor Barrier Costs in Burbank
| Job Type | Typical Range | What Moves the Price |
|---|---|---|
| Demilec vapor barrier replacement, 800-1,200 sq ft crawl space | $2,800-$4,200 | Stem wall height, number of penetrations, whether existing barrier is mechanically fastened or glued |
| Demilec HFO spray foam encapsulation, full floor and stem wall | $4,500-$6,500 | Pass thickness required, need for conditioned-air supply to crawl space, dehumidifier integration |
| SEALECTION 500 repair, localized delamination | $1,800-$3,200 | Extent of substrate damage, accessibility, whether we can salvage the intact sections |
| AgriThane 7520 full removal and replacement | $5,200-$7,800 | Hazmat handling requirements, soil-gas mitigation integration, disposal fees |
These are real numbers for Burbank properties we’ve worked, not national averages. A 1,000-square-foot crawl space in the flatlands near Victory Boulevard runs differently than the same footprint on a hillside lot with a stepped foundation. Call (213) 816-1699 for an exact quote - estimates are free, and we provide a Free Second Opinion on any written estimate you’ve already received.
Why Burbank Homeowners Call Topside Attic Insulation Burbank for Demilec Work

We’ve been working Burbank crawl spaces since 2016, including the tight clearance jobs under 1950s ranch homes in Magnolia Park where the original Demilec installer had to work on their back with a headlamp. Our crew knows the difference between a SEALECTION 500 batch from 2012 and 2018 just by the primer color, because we’ve peeled back enough failed installations to build that reference library.
Every job leaves with a written scope, written warranty, and Documented Photo Record. On encapsulation jobs, you get before-and-after blower-door numbers so you can verify the air-sealing result yourself. If we install it and it’s not right, the 365-Day Done Right Promise means we make it right - no dispute, no delay.
We also service Reflectix radiant barrier systems, so if your Burbank home has a hybrid insulation stack with Demilec below and Reflectix above, one crew handles both. No subcontractor handoffs, no blame-shifting when the interfaces don’t match.
FAQs
No. Demilec’s product warranty covers manufacturing defects, not installation workmanship, and as an independent Demilec service provider we use materials and methods that meet or exceed Demilec’s published specifications. The original installer’s workmanship warranty is separate from the material warranty, and that installer may claim their warranty is voided by third-party work. We document our methods with photos and written scope so you have evidence if that dispute arises. Call (213) 816-1699 if you’re facing a warranty conflict - we’ll review your paperwork with you.
Demilec discontinued AgriThane 7520 in 2017 and does not manufacture replacement stock. We source compatible HFO formulations from Demilec’s current catalog or, where the application demands it, quality aftermarket two-component systems that match the original density and closed-cell content. We never represent aftermarket material as OEM, and we specify which we’re using in your written scope before work starts.
Localized SEALECTION 500 delamination under 15% of total area can often be repaired with mechanical termination and patch welding for $1,800-$3,200. Once delamination exceeds 30% or the substrate concrete is spalling, full replacement is more cost-effective than chasing progressive failure. We give you both numbers in the written estimate so you can decide based on total cost of ownership, not just today’s invoice. Call (213) 816-1699 for a free assessment.
Most vapor barrier replacements finish in one day; full HFO spray foam encapsulations take two days including cure time and post-installation testing. We can typically inspect and price within 24 hours of your call, and schedule work within 48 hours of written approval. Our live-answered phone line is open 24/7, including weekends.
Demilec’s SEALECTION 500 and early HFO formulations relied heavily on substrate primer adhesion in an era when many Burbank installers skipped mechanical fastening to cut labor hours. The product itself performs to spec when installed correctly; the failure mode we see most is installation protocol deviation, not material defect. Our crews use termination bars and welded seams as standard, not upgrades, because Burbank’s clay soil moisture profile punishes shortcuts.
Written by Wes Okafor, Owner & Lead Insulation Technician, Topside Attic Insulation Burbank at Topside Attic Insulation Burbank, serving Burbank and nearby areas.