Demilec Crawl Space Encapsulation & Vapor Barrier in Tustin: What to Know First
We provide independent Demilec crawl space encapsulation and vapor barrier service in Tustin, typically scheduling within 48 hours and completing most jobs in a single day. Most Tustin crawl space encapsulation projects run between $2,800 and $6,500 depending on square footage, existing moisture damage, and whether the Demilec foam needs partial removal before we can seal the envelope properly. We are not affiliated with or authorized by Demilec - we are an independent service provider - which means we work with what is actually in your crawl space, not what a factory manual says should be there.
This page is for Tustin homeowners who have Demilec spray foam or insulation in their crawl space and are dealing with moisture intrusion, odor, deteriorating foam, or a failed vapor barrier. If you are seeing white foam turning yellow or brown, smelling a chemical off-gas in humid weather, or finding standing water on your polyethylene sheeting, the fix is not more of the same product. Call (657) 286-7673 for a free written estimate - we will read your crawl space with you, show you what we found on our tablet, and leave you with a flat price before any work starts.
How Demilec Products Fail - and How We Fix Them
- Demilec Heatlok HFO Pro yellowing and surface degradation in Tustin crawl spaces. The HFO blowing agent in this closed-cell series is hydroscopic under sustained humidity above 70% RH, which Tustin sees regularly from June through October when marine layer moisture gets trapped against foundation vents. We have pulled down Heatlok HFO Pro in the Tustin Legacy area that looked intact from above but had turned to a crumbly, water-absorbing mass on the underside facing the dirt. Our fix: remove the compromised foam back to clean substrate, dry the cavity with commercial dehumidification, then install a proper vapor barrier and replacement insulation - often Rockwool or a different foam chemistry - with a continuous 6-mil polyethylene ground cover sealed at all seams.
- Demilec Sealection 500 open-cell foam holding moisture in rim joists. Open-cell foam is vapor-permeable by design, which is fine in an above-grade wall but problematic in a crawl space where it is sprayed directly against rim joists without a vapor barrier backing. In Tustin’s older homes near Old Town, we regularly find Sealection 500 that has become a sponge for soil moisture, promoting mold on the joist face and compromising the wood. We cut away the affected foam, treat the joist if structurally sound, then install a rigid vapor barrier with sealed edges before any new insulation goes in.
- Demilec Heatlok XT separation from concrete or block foundations. The XT series uses a higher-density formulation that can delaminate from damp concrete when applied without proper primer or when the foundation was not fully cured. In Tustin’s post-2000 construction, we see this where builders sprayed foam directly on foundation walls that were still releasing construction moisture. The gap becomes a convection channel - air and moisture loop behind the foam. We remove the detached sections, apply a foundation-grade waterproofing primer, then reinstall with mechanical fastening at the top edge and a dimpled drainage mat if hydrostatic pressure is present.
- Demilec spray foam applied over an existing failed vapor barrier, trapping water. This is not a product defect but an installation error we see repeatedly: a contractor sprayed Demilec closed-cell foam directly over torn or improperly lapped 6-mil poly, essentially laminating the moisture problem in place. In one Tustin Ranch job, we found a full inch of standing water between the poly and the foam, with anaerobic bacterial growth causing a sulfur smell. We strip the entire assembly, dry the soil with forced air and desiccant dehumidification, install a new 12-mil reinforced vapor barrier with sealed perimeter piers, then reinsulate. Seal the leaks first. Then insulate. The R-value on the bag means nothing if conditioned air is moving through the gap around that recessed can.
- Demilec foam degradation from rodent activity in unsealed crawl spaces. Rats and mice tunnel through open-cell foam for nesting material; closed-cell is less vulnerable but not immune if they are determined. Demilec does not contain pest deterrent additives. In Tustin’s hillside homes near Peters Canyon, where rodent pressure is higher, we remove contaminated foam sections, install rodent-proofing at all penetration points with 1/4-inch hardware cloth, then reinsulate with materials the customer can inspect and maintain. Every job gets a Documented Photo Record so you have evidence for insurance or future sale disclosure.
Our Demilec Crawl Space Encapsulation & Vapor Barrier Process
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Call and scope. A live person answers 24/7. We ask about your home’s age, crawl space access dimensions, what you are seeing or smelling, and whether you know the Demilec product line installed. We schedule a site visit, usually within 48 hours in Tustin.
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Inspection and diagnostics. We enter the crawl space with moisture meters, thermal imaging, and a borescope for tight spots. We identify the Demilec series if possible - Heatlok HFO Pro, Sealection 500, Heatlok XT - and document failure mode, moisture source, and structural condition. You get the photos on our tablet before we climb out.
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Written price and scope. Under Haven Standard Clause 1: flat price, written scope, written warranty before anyone lifts a tool. No work starts without it. If you have a competing estimate, we offer a Free Second Opinion - we will read it with you line by line.
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Removal and preparation. We remove compromised Demilec foam with controlled methods - no grinding that releases isocyanate dust into your HVAC return. We dry the space with commercial dehumidification, treat mold-affected framing if present, and repair or replace the vapor barrier.
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Reinsulation and air sealing. We seal all penetrations, rim joists, and the sill plate before installing replacement insulation. On applicable jobs, we run a blower-door test - pressurizing the house to 50 pascals to measure air leakage in CFM50 - before and after, so you have a number for what changed.
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Documentation and closeout. You receive a Documented Photo Record, written R-value report, before-and-after blower-door readings if applicable, and the 365-Day Done Right Promise in writing. We leave the crawl space clean enough to store holiday decorations.
Before
AfterWhat Demilec Crawl Space Encapsulation & Vapor Barrier Costs in Tustin
Most Demilec crawl space remediation jobs in Tustin fall between these ranges:
- Partial vapor barrier replacement with localized Demilec foam removal: $2,800-$4,200
- Full encapsulation with complete Demilec removal, new 12-mil reinforced barrier, and replacement insulation: $4,500-$6,500
- Complex jobs with foundation drainage, sump pump, or structural drying: $6,500-$9,500+
What moves the price: crawl space square footage and headroom (tight access adds labor), extent of Demilec degradation, whether the foam is closed-cell requiring mechanical removal versus open-cell that can be scraped, presence of standing water or mold requiring remediation before encapsulation, and whether we are also air-sealing the floor system above. We also service Reflectix radiant barrier products if your crawl space has a hybrid insulation system.
Call (657) 286-7673 for a free written estimate - we will give you the flat price before any work starts, and estimates are always free.
Why Tustin Homeowners Call Topside Attic Insulation Tustin for Demilec Work
We have been independently owned and operated under The Haven Standard since 2016, and we have sealed and insulated more than 9,000 homes - every one with a written price before work started and a documented record when the crew left. Wes Okafor and our technicians know Demilec’s product line from hands-on removal and replacement, not from a distributor brochure. We carry materials from Owens Corning, Johns Manville, Knauf, Rockwool, CertainTeed, Icynene, Demilec, and GreenFiber - no proprietary lock-in means we choose what performs for your specific crawl space condition.
Our 365-Day Done Right Promise applies to all completed work. Calls are answered by a live person 24/7. Background-checked, uniformed technicians arrive on schedule with a text when they are on the way. And we publish before-and-after blower-door numbers on every applicable job so you can verify the air-sealing result in a single figure.
FAQs
Demilec’s product warranty covers manufacturing defects, not installation errors or environmental degradation, and it does not extend to third-party modifications. As an independent Demilec service provider, we document the condition of the foam before removal with photos and moisture readings so you have a record if a manufacturing claim is relevant. Call (657) 286-7673 and we will review what warranty coverage might still apply to your installation.
We can source Demilec products through distribution when appropriate, but we often recommend alternative chemistries - particularly in crawl spaces with chronic moisture - because the original formulation failed in that environment. We explain the trade-off: OEM maintains material consistency for small repairs, but a different product may perform better long-term. Your written scope specifies exactly what we will install and why.
Partial repair is cheaper only if the failure is localized and the remaining foam is dry, well-adhered, and accessible for inspection. In most Tustin crawl spaces we enter, the moisture problem has spread beyond what spot repair can address, and full encapsulation with a new vapor barrier is the more cost-effective 10-year solution. We will show you both options in your written estimate.
Most Demilec crawl space encapsulation jobs in Tustin are scheduled within 48 hours and completed in one to two days. If standing water or active mold requires drying before encapsulation, add 24-72 hours for dehumidification. Call (657) 286-7673 for availability - estimates are free and we will give you a written timeline with the price.
Yes. We encounter Reflectix radiant barriers in hybrid systems where a previous installer layered products without proper air sealing. We can remove, replace, or integrate Reflectix with a proper encapsulation system depending on your crawl space condition and goals.
Written by Wes Okafor, Owner, Topside Attic Insulation Tustin at Topside Attic Insulation Tustin, serving Tustin and nearby areas.