Demilec Crawl Space Encapsulation Nationwide

Demilec Crawl Space Encapsulation: The Orange County Owner’s Guide

Demilec crawl space encapsulation in Orange County typically costs $3,800 to $8,500 installed, depending on square footage, existing moisture damage, and whether you choose Heatlok HFO or a closed-cell Demilec formula. We stock Demilec spray foam on our trucks and can usually begin encapsulation within 3 to 5 business days of your written estimate. Most Orange County homeowners discover a problem the same way: they smell must in the hallway, see condensation on the crawl space access door, or find a floor that feels damp through the carpet. The existing encapsulation liner has torn, peeled away from the foundation wall, or was never properly sealed at the sill plate. What started as a 12-mil vapor barrier from a previous contractor has become a moisture pump feeding humid air into every room above it.

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Which Demilec Models This Applies To

Demilec makes two spray foam lines that matter for Orange County crawl spaces: Heatlok HFO Pro (closed-cell, roughly R-7.4 per inch) and Sealection 500 (open-cell, roughly R-4.1 per inch, but vapor-permeable). If your existing encapsulation is failing, you need to know which was originally sprayed before anyone quotes a repair, because they do very different jobs in a crawl space. Closed-cell Heatlok is the vapor barrier itself. Open-cell Sealection needs a separate 12-mil liner over it to block ground moisture, and in Orange County’s marine layer humidity, skipping that liner is exactly why we see open-cell crawl spaces sweating through summer. The quickest way to identify what you have: look for the white or pale yellow foam with a fine cell texture (that’s Heatlok), or a softer, sponge-like foam you can press a thumb into (that’s Sealection). If the foam is crumbly, chalky, or pulling away from the stem wall, it’s failing. We also keep aftermarket equivalents from Johns Manville and CertainTeed on the truck for touch-ups, but for Demilec-specific warranties, OEM product matters. Aspen Attic Insulation Orange County is an independent installer, not a Demilec distributor or affiliate.

What We Stock on the Truck

• Heatlok HFO Pro kits – for full re-spray or gap sealing on existing closed-cell jobs
• Sealection 500 kits – for bonus-room and vented crawl space floors where vapor-permeable foam is correct
• 12-mil reinforced vapor barrier – taped and sealed to stem walls, piers, and the sill plate
• Demilec-compatible caulk and mastic – for sealing foam seams, plumbing penetrations, and rim joist gaps

Signs Your Demilec Crawl Space Encapsulation Is Failing

• Condensation on the crawl space door or vent covers. Warm Orange County air hits the cool metal access panel, and if the encapsulation is compromised, that air is carrying crawl space moisture with it. You’ll see water beads on the inside of the door in the morning.
• Musty smell in the living room or hallway. That’s ground moisture working through the floor assembly. Once the vapor barrier seam fails at the foundation wall, nothing stops soil gas from rising. Orange County’s clay-heavy soil in areas like Tustin and Mission Viejo holds moisture longer than sandy coastal soil, so inland homes usually smell it first.
• Floor feels damp through carpet or hardwood. Not wet to the touch, just cool and clammy. That’s humidity, not a leak. It’s the signature of a torn liner or foam that’s de-bonded from the stem wall.
• Insulation sagging or falling from the crawl space ceiling. Fiberglass batts were never right for a humid crawl space in the first place, and once they absorb moisture, they pull down from the floor joists. We replace them with closed-cell Demilec foam that won’t sag.
• Bugs, especially termites or roaches. Damp wood and soil contact invite them in. Orange County has active drywood and subterranean termite pressure year-round. Encapsulation that’s failing becomes a termite highway into your floor joists.

Replacement Cost & What’s Included

Here’s what a full Demilec encapsulation runs in Orange County, based on a typical 1,000 to 1,400 square foot crawl space. Your number moves with square footage, access difficulty, and how much old material needs removal.

Every job gets a written price before we touch the house. You’ll see the parts, labor, prep, and cleanup broken out line by line, and that price doesn’t change unless we find something you’ve approved in writing mid-job. The work is covered for 365 days by our Done Right Promise. If the encapsulation fails within that year, we come back and fix it at no charge. That’s labor and materials, in writing.

DIY or Call Us?

Some parts of this you can absolutely check yourself. Open the crawl space door, shine a flashlight at the stem wall, and look for foam pulling away from the concrete or a liner that’s ripped at the seams. Take photos. That gives you a reference point before anyone quotes you a repair. What you shouldn’t do is re-spray Demilec foam yourself. The two-part kits require proper mixing temperatures, a respirator, and a full Tyvek suit. Get the ratio wrong and the foam won’t cure properly, which means you’ve spent $900 on a kit and still need a professional. Orange County’s heat also makes summer application unforgiving: foam sprayed on a 95-degree stem wall cures too fast and loses adhesion. That’s a job for someone who has worked with the material enough to know when conditions are wrong before they pull the trigger. If you’re not sure whether your encapsulation can be salvaged, call (559) 249-4794 and describe what you see. We’ll tell you honestly whether you need a repair or a full re-spray, and what each costs in writing.

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