Johns Manville Crawl Space Encapsulation Nationwide

Johns Manville Crawl Space Encapsulation: The Cedar Park Owner’s Guide

We stock and install Johns Manville-compatible crawl space encapsulation systems in Cedar Park, with most complete installs running $3,200-$5,800 depending on crawl square footage and existing moisture damage. Same-day service is available when we have your liner spec in stock, which we do for the common JM 10-mil and 12-mil woven polyethylene grades. Most Cedar Park homeowners discover their encapsulation has failed when they notice a musty smell returning after months of absence, or when their dehumidifier starts running continuously in a crawl space that was supposed to be sealed tight.

Call (737) 245-6428

Which Johns Manville Models This Applies To

Johns Manville produces crawl space liners under their CrawlShield and ComfortTherm product families, with the 10-mil white woven polyethylene (SKU prefix JM-CSW) and 12-mil reinforced cross-laminated (JM-CSR) being the two we encounter most in Cedar Park homes built between 2005 and 2020. The label is usually printed along the seam edge every four feet; if yours is buried, measure thickness with a micrometer at a cut edge, woven JM liners read 9.5-10.5 mil under caliper, not the 6-mil hardware-store vapor barrier that fails within two seasons in Central Texas clay soil.

We also stock Reflectix radiant barrier products for crawl space ceiling applications where the original install paired a JM liner with reflective insulation.

OEM Johns Manville liner carries the full factory spec and matching warranty documentation. Quality aftermarket equivalents from Poly-America and Raven Industries match the mil rating and ASTM E1745 Class A vapor-retarder certification at 15-25% lower material cost, though they won’t carry the JM brand warranty card. For resale or builder-warranty situations in Cedar Park’s newer developments like Buttercup Creek or Ranch at Brushy Creek, we typically recommend staying OEM. For older homes where the original warranty has expired, the aftermarket Class A equivalent performs identically in our blower-door and moisture-meter verification.

Topside Attic Insulation Cedar Park is an independent service provider, not affiliated with Johns Manville.

Signs Your Johns Manville Crawl Space Encapsulation Is Failing

• Return of musty odors in the living space. The JM liner’s taped seams have separated or the wall attachment has pulled free, letting soil gases and moisture bypass the barrier. In Cedar Park’s expansive clay, seasonal soil movement works tape loose at the perimeter faster than in sandy regions.
• Dehumidifier running more than 12 hours daily. A properly sealed JM system should hold relative humidity below 60% with intermittent dehumidifier cycling. Constant operation means the envelope is leaking faster than the unit can extract.
• White mineral deposits (efflorescence) on the liner surface. This indicates moisture is migrating through or around the barrier, carrying dissolved salts from the concrete or soil. On JM 10-mil woven product, efflorescence usually starts at seam gaps where the polyethylene has delaminated from the scrim.
• Sagging or ponding on the liner floor. The original install may have used insufficient overlap (JM spec calls for 12-inch minimum seam overlap, taped) or the liner has been punctured by stored items or rodent activity. Standing water above the liner means it’s no longer shedding to the perimeter drain.
• Insect or rodent activity in previously dry crawl space. Once the JM seal is compromised, humidity rises and pheromone trails reactivate. We find this frequently in Cedar Park homes near Williamson County greenbelt corridors where armadillos and field mice already pressure the foundation.

Replacement Cost & What’s Included

In Cedar Park, a full Johns Manville-compatible crawl space encapsulation replacement typically runs $3,200-$5,800 installed, with the spread driven by three factors: crawl square footage (800 sq ft vs 2,000+ sq ft), whether the existing liner removal reveals mold remediation needs, and whether the perimeter wall seal requires new mechanical fastening into block or poured concrete.

Every encapsulation job includes our Documented Photo Record, a written scope signed before work starts, and the 365-Day Done Right Promise. We don’t charge separately for the moisture-meter verification we perform 48 hours after install.

DIY or Call Us?

There’s safe reconnaissance and there’s work that belongs to a crew. A homeowner can verify the failure by checking the dehumidifier runtime, shining a flashlight along seam lines for gaps, and confirming the liner is still mechanically fastened at the perimeter walls. What you should not do: crawl under a pier-and-beam with compromised structural supports, attempt to remove a liner that may be hiding active mold colonies without respiratory protection, or re-tape seams with consumer-grade duct tape that off-gasses and fails in 90 days.

The JM 12-mil liner is heavy, 45-60 pounds per roll for a typical Cedar Park crawl, and cutting it to fit around piers and HVAC plenums without leaving gaps takes experience. We’ve replaced three DIY encapsulations this year in Cedar Park alone where the homeowner’s seam overlap was insufficient or the wall attachment used adhesive that failed in the first summer heat cycle. Call (737) 245-6428 and we’ll read your situation with you, no charge for the assessment.

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