Demilec Crawl Space Encapsulation & Vapor Barrier in Leander: What to Know First
As an independent Demilec service provider, we handle crawl space encapsulation and vapor barrier work on Demilec-insulated homes across Leander, including the Crystal Falls neighborhood and the older ranch-style builds along Bagdad Road. Most Demilec crawl space jobs we see run two to four days from diagnostic to final walkthrough, and every one starts with a written price before any work starts - that’s Haven Standard Clause 1, no exceptions. If you’re seeing musty odors, sagging insulation, or moisture pooling on your vapor barrier and your crawl was originally insulated with Demilec product, this page is for you. Call (737) 252-7159 for a free estimate and we’ll read your situation with you.
How Demilec Products Fail - and How We Fix Them
- Demilec Heatlok HFO Pro separation from band joists in humid crawl spaces. The HFO Pro’s high closed-cell density can create a vapor-lock effect when applied directly to band joists without proper substrate prep. In Leander’s spring humidity spikes, we’ve seen this foam pull away from the wood, creating a gap that channels outdoor air straight into the floor cavity. We cut back the failed section, apply a masonry-compatible primer where needed, and reinstall with proper mechanical fastening at the bond line.
- Demilec Sealection 500 degradation from groundwater wicking in low-lying Leander areas. Sealection 500 is an open-cell formula, and open-cell foam acts like a sponge if the vapor barrier below it fails. Near the San Gabriel River floodplain, we’ve pulled saturated Sealection that weighed three times its dry mass. We remove the waterlogged foam, install a 20-mil reinforced polyethylene vapor barrier with sealed seams, then replace with closed-cell product or a hybrid system depending on the crawl height.
- Demilec Heatlok XT overspray onto existing vapor barriers, compromising seam integrity. Heatlok XT expands aggressively, and previous contractors sometimes let it lap onto poly sheeting. The cured foam creates hard points that tear the vapor barrier during seasonal soil movement. We map the overspray with a FLIR scan, trim it flush with an oscillating multi-tool, then lay new cross-lapped poly with butyl-tape seams rated for Texas clay soils.
- Demilec open-cell foam installed without ignition barrier in accessible crawl spaces. Code in Williamson County requires an ignition barrier on open-cell foam in crawl spaces over 22 inches in height. We’ve found Demilec open-cell jobs in Leander’s 1990s subdivisions with no barrier at all. We don’t just add the barrier; we verify the foam density with a core sample first, because some “open-cell” installs we’ve encountered were actually mislabeled low-density closed-cell that needs different treatment.
- Demilec retrofit jobs where new foam was shot over old fiberglass with no air sealing. This isn’t a Demilec product failure - it’s a sequencing failure we see constantly. A Leander homeowner near Vista Ridge had Demilec closed-cell sprayed directly over compressed R-19 fiberglass at the rim joist. The fiberglass was wet, the foam couldn’t bond, and the whole assembly was rotting the sill plate. We removed both layers, dried the joist bay with a desiccant dehumidifier for 48 hours, sealed all penetrations with acoustic sealant, then applied new foam to a clean, dry substrate.
Our Demilec Crawl Space Encapsulation & Vapor Barrier Process
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Call and schedule. A live person answers, or you can text. We ask about your home’s age, the original install date if you know it, and what you’re seeing - musty smells, cold floors, visible sagging. We schedule a diagnostic, not a sales pitch.
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On-site diagnostic with documentation. Wes Okafor or one of our techs arrives with a FLIR camera, moisture meter, and blower-door rig if the crawl connects to conditioned space. We identify the Demilec product line by visual inspection and core sample where needed. You get a Documented Photo Record starting at this visit.
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Written scope and price. Before any work starts, you receive a flat price, written scope, and written warranty - Haven Standard Clause 1. If you have a competing estimate, we provide a Free Second Opinion and read it with you line by line.
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Prep and air sealing first. Seal the envelope first. Then fill it. We seal all penetrations, top plates, and duct boots with acoustic sealant or two-part foam before any new insulation goes in. On applicable jobs, we run a blower-door test before and after so you can see the CFM50 change.
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Demilec-specific repair or replacement. We source materials from our supplier network including Demilec, Owens Corning, Johns Manville, and others - no proprietary lock-in. OEM when it matters for warranty continuity, quality aftermarket when the performance spec matches and the price serves you better.
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Final test, photo record, and walkthrough. We verify insulation depth with a calibrated ruler card on every job. You leave with a written report, before-and-after readings where applicable, and the 365-Day Done Right Promise in writing.
Before
AfterWhat Demilec Crawl Space Encapsulation & Vapor Barrier Costs in Leander
Most Demilec crawl space jobs we complete in Leander fall between these ranges:
- Vapor barrier replacement only (20-mil reinforced poly, sealed seams): $1,800 - $3,200 for a typical 1,200-2,000 sq ft footprint
- Partial Demilec foam removal and reinstallation (band joists or rim area): $2,400 - $4,500
- Full crawl encapsulation with new vapor barrier, closed-cell foam at rim, and dehumidifier prep: $5,500 - $9,800
- Remediation with water-damaged structural repair (sill plate, band joist replacement): $8,000 - $14,000+
What moves the price: crawl height (less than 18 inches requires specialized equipment), extent of water damage to structural members, whether the existing Demilec product requires full removal versus localized repair, and accessibility - some Leander crawl spaces off Crystal Falls Parkway have HVAC ducts hung at 14 inches that we have to work around or temporarily relocate. Every estimate is free, every price is written before work starts, and we never upsell a full encapsulation when a targeted repair will solve it. Call (737) 252-7159 for your exact number.
Why Leander Homeowners Call Topside Attic Insulation Leander for Demilec Work
We’ve sealed and insulated over 9,000 homes since 2016, and a growing share of our crawl space calls in Leander involve Demilec product that was installed correctly but failed due to moisture management issues, or was installed poorly and needs sequencing correction. Our techs know the difference between Heatlok HFO Pro and Sealection 500 by sight and density, and we carry both OEM Demilec materials and compatible alternatives from Reflectix and other manufacturers so you’re not locked into a single supplier. The 365-Day Done Right Promise applies to every job, backed by a written scope you receive before anyone lifts a tool. Calls are answered by a live person 24/7, and our technicians are background-checked, uniformed, and named - you’ll get a text when yours is on the way.
FAQs
Demilec’s material warranty covers defects in manufacture, not installation or subsequent modification. The installer’s workmanship warranty is what typically governs encapsulation and vapor barrier work, and that warranty travels with the original contractor. We provide our own written warranty on all work performed, and we document the existing Demilec product condition with photos before we start so there’s no dispute about what was pre-existing versus what we addressed. Call (737) 252-7159 and we’ll review your specific install documentation with you.
Most targeted repairs - vapor barrier replacement, localized foam removal and reinstallation - take one to two days. Full encapsulations with dehumidifier integration run three to four days. We don’t quote timelines without seeing the crawl space first because Leander’s clay soils can slow vapor barrier seam work when we hit unexpected moisture patterns. Estimates are free and include a realistic schedule.
If the Demilec foam is dry, well-bonded, and at proper density, we repair around it and save you the removal cost. If it’s waterlogged, delaminated, or contaminated with rodent activity, removal is the only durable option - and we say so directly. We’ve walked away from jobs where a homeowner wanted a cheap repair on foam that was structurally compromised. The written price we give you reflects what will actually last, not what sounds easy. Call for a free diagnostic and we’ll show you what we found.
Yes. We source from Owens Corning, Johns Manville, Knauf, Rockwool, CertainTeed, Icynene, Demilec, and GreenFiber. R-value is a measured thermal resistance, not a brand-specific property. We match or exceed the existing assembly’s performance and document the spec in your written report. The choice of material depends on your crawl space conditions - closed-cell for rim joists in high-humidity areas, open-cell only where proper vapor management and ignition barriers are in place.
We answer calls live 24/7 and typically schedule diagnostics within 24-48 hours for active water intrusion or structural concerns. We don’t manufacture urgency, but we also don’t leave homeowners with saturated foam against sill plates any longer than necessary. If you’re seeing standing water or smelling mold, call (737) 252-7159 now - we’ll get a tech out and give you a written price before any work starts.
Ready to get your Demilec crawl space sorted? Call (737) 252-7159 for a free estimate. We’ll arrive on schedule, diagnose what you actually have, and leave you with a written price, a written scope, and a clear picture of what fixed looks like.
Written by Wes Okafor, Owner, Topside Attic Insulation Leander at Topside Attic Insulation Leander, serving Leander and nearby areas.