Johns Manville Crawl Space Encapsulation & Vapor Barrier Nationwide

Johns Manville Crawl Space Encapsulation & Vapor Barrier in Boerne: What to Know First

We provide independent Johns Manville crawl space encapsulation and vapor barrier service in Boerne, with most jobs completed in one to two days and a written price delivered before any work starts. As an independent Johns Manville service provider, we carry the full line of JM vapor barrier and encapsulation materials, including the PermaR products and CleanSpace-compatible retrofits we see in Hill Country homes. Most Boerne crawl spaces we encounter run 1,200 to 2,400 square feet, and a complete encapsulation with vapor barrier, sealed vents, and dehumidification prep typically falls between $4,200 and $8,500 depending on access, existing damage, and whether the foundation needs seam welding or mechanical fastening. Call (830) 529-7780 for a free estimate with a written scope.

Call (830) 529-7780

How Johns Manville Products Fail - and How We Fix Them

• PermaR 10 mil vapor barrier embrittlement in Boerne’s limestone crawl spaces. The alkaline soil moisture wicking through limestone foundation walls attacks the polyethylene over time, causing the barrier to craze and split at fold points. We see this most in older homes near the Cibolo Nature Center where the water table shifts seasonally. Our fix: pull the compromised sheet, treat the walls with a pH-neutral masonry sealer, then install a reinforced 20 mil cross-laminated barrier with mechanical fastening at stress points rather than adhesive alone.
• CleanSpace liner delamination at the sill plate in homes with negative grade. When runoff flows toward the foundation, hydrostatic pressure pushes water behind the liner at the sill plate junction. The adhesive bond fails, and you get a bubble of trapped water that looks like a liner defect but is actually a drainage problem. We install a dimpled drainage mat and interior perimeter channel before re-securing the liner, so the water has somewhere to go.
• JM fiberglass batt degradation in vented crawl spaces. Standard Kraft-faced batts installed in Boerne’s humid crawl spaces absorb moisture, compress, and drop from the floor joists. The facing becomes a mold substrate. We remove the fallen, degraded batts, seal the vents, and replace with JM formaldehyde-free batts only after encapsulation is complete, or spec closed-cell spray foam if the budget allows.
• PermaR seam tape failure at temperature extremes. The pressure-sensitive adhesive on JM seam tape can release when crawl space temperatures swing from 45°F in January to 95°F in August, which is standard in unconditioned Boerne crawl spaces. We double-seam critical junctions with JM-approved tape plus a mechanical batten strip at the perimeter, and we specify butyl-based tape on jobs where the homeowner wants the longest possible service interval.
• Inadequate mil thickness spec’d by original builders. We regularly find 6 mil JM vapor barrier installed by tract builders in 2015-2019 Boerne subdivisions. Six mil tears on the gravel during installation and punctures within three to five years. We upgrade to 12 mil minimum for storage crawl spaces and 20 mil for conditioned or high-traffic applications, with a written mil spec in the scope so there’s no confusion about what was promised.

Our Johns Manville Crawl Space Encapsulation & Vapor Barrier Process

1. 1
   Site survey and moisture mapping. We measure relative humidity at three points, check for standing water, and photograph existing JM materials and their condition. You get the photos before we leave.
2. 2
   Blower-door and pressure-differential testing. We run a blower-door test on the living space to quantify how much conditioned air is being pulled through the crawl space via stack effect. The number goes on paper in pascals.
3. 3
   Written scope with line-item pricing. Under Haven Standard Clause 1, you get a flat price, written scope, and written warranty before anyone lifts a tool. No work starts without it.
4. 4
   Prep, removal, and air sealing. We remove degraded materials, seal sill plates and penetrations with JM-compatible sealants, and address drainage before any new barrier goes down. Seal the envelope first. Then fill it.
5. 5
   JM vapor barrier or encapsulation system installation. We specify the exact JM product line, mil thickness, and fastening method. OEM materials or quality equivalents per your approval.
6. 6
   Post-work documentation. Final blower-door reading, updated pressure-differential report, Documented Photo Record of completed work, and the 365-Day Done Right Promise in writing.

What Johns Manville Crawl Space Encapsulation & Vapor Barrier Costs in Boerne

What moves the price: access clearance (some Boerne hillside homes have 18-inch crawl space height), existing mold or pest damage requiring cleanout, and whether the foundation perimeter needs interior drainage. We also carry Reflectix radiant barrier products when a hybrid system makes sense for the application.

Call (830) 529-7780 for a free estimate - we’ll read any competing written quote with you as part of our Free Second Opinion.

Why Boerne Homeowners Call Topside Attic Insulation Boerne for Johns Manville Work

We’ve sealed and insulated over 9,000 homes since 2016, and the ones in Boerne taught us something specific: the Hill Country’s combination of limestone substrate, seasonal humidity swings, and negative-grade lots means a crawl space solution that works in San Antonio often fails here. Wes Okafor runs a blower-door test before and after every job, then hands you a printed pressure-differential report in pascals so the performance change is documented, not claimed. Our technicians are background-checked and uniformed, calls are answered by a live person 24/7, and every job carries the 365-Day Done Right Promise backed by a written scope and warranty delivered before work starts. We source materials from Johns Manville, Owens Corning, Knauf, Rockwool, and others - no proprietary lock-in, so we spec what’s right for your house.

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