Johns Manville Crawl Space Encapsulation Nationwide

Johns Manville Crawl Space Encapsulation: The Burbank Owner’s Guide

We stock and install Johns Manville crawl space encapsulation materials throughout Burbank, with most vapor barrier replacements running $2,800-$5,400 installed depending on square footage and access. Same-week scheduling is typical, and we carry the common Johns Manville liner widths on our trucks. Most Burbank homeowners discover the problem the same way: a musty smell drifting up through the floorboards, or standing water under the house after a heavy rain. The plastic liner that should be keeping moisture out has torn, pulled away from the foundation wall, or was never properly sealed in the first place.

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Which Johns Manville Models This Applies To

Johns Manville doesn’t sell crawl space encapsulation as a single pre-packed kit the way some manufacturers do. Their system is built from separate components: the vapor barrier liner (most commonly the 10-mil or 12-mil reinforced poly in 10-foot and 12-foot roll widths), seam tape, and fastening pins. The liner product most Burbank homes use is spec’d under the Johns Manville crawl space liner line, and the key compatibility detail is the reinforcement layer. The reinforced poly has a white or gray woven scrim sandwiched between two poly layers, and you can identify it by the grid pattern visible when you hold it up to light.

One compatibility gotcha we run into in Burbank regularly: not all seam tapes bond to Johns Manville’s reinforced poly the same way. The liner has a slightly textured surface from the scrim layer, and cheap off-brand tape will fail at the seam within a season or two. We use the JM-specified tape or a proven equivalent tested for this exact surface. If you’re deciding between OEM Johns Manville liner and a quality aftermarket equivalent, the honest answer is that the aftermarket options from brands like Raven or Americover perform comparably at 10-mil thickness and above. The difference is usually warranty documentation and roll-to-roll consistency. For the liner itself, we install both, but we don’t install anything under 10-mil in a Burbank crawl space. Below that, it tears too easily during installation and doesn’t survive the first time someone has to crawl under the house to check a pipe.

We’re an independent contractor, not affiliated with Johns Manville, so we can install whatever liner spec actually fits your crawl space rather than pushing one brand regardless of the job. We also stock Reflectix radiant barrier for crawl space wall applications where heat gain from the foundation is contributing to the problem.

Signs Your Johns Manville Crawl Space Encapsulation Is Failing

• Musty odor in the living space. When a seam opens or the liner tears, soil moisture evaporates directly into the crawl space air and migrates up through floor penetrations. If you smell it most strongly in the morning or after rain, the liner is the first thing to check.
• Visible standing water or damp soil under the house. A properly sealed liner keeps ground moisture below the plastic. If you see pooled water on top of the liner or wet patches at the foundation wall edge, the seal has failed or was never mechanically fastened correctly.
• Floor feels cold in winter. Burbank crawl spaces stay cool, and when the liner fails, that cold, damp air infiltrates the floor system. Rooms over the crawl space run noticeably colder than rooms over a slab or garage.
• Mold growth on floor joists or subfloor. This is the late-stage symptom. Once you can see mold or mildew staining on the wood under the house, the barrier has been compromised for months. You need the liner fixed and the wood treated, not just covered up.
• Insulation falling from between floor joists. When fiberglass batts get wet from crawl space moisture, they sag and pull away from the subfloor. If you see drooping insulation in the crawl space, the vapor barrier above it isn’t doing its job.

Replacement Cost & What’s Included

For a Burbank crawl space replacement of an existing Johns Manville liner, expect to pay $2,800-$5,400 installed. Small crawl spaces under 800 square feet with easy access run at the low end, while larger footprints, tight clearance, or failed liners that require old material removal push toward the high end. Every job we quote includes removal of the old liner (even if it’s torn and buried under debris), full coverage of the dirt floor with 10-mil or 12-mil reinforced poly, mechanical fastening to the foundation walls, seam taping with compatible tape, and sealing around piers and plumbing penetrations. The 90-Day Done Right Promise covers the installation, and the liner material itself carries the manufacturer’s warranty, which for Johns Manville reinforced poly runs 15-20 years when properly installed.

DIY or Call Us?

The crawl space liner itself isn’t dangerous to install the way a garage door spring or electrical panel is, but the honest reality is that most DIY encapsulation jobs in Burbank fail for the same reason: the homeowner can’t physically access the far corners of a 24-inch-tall crawl space, and a liner that isn’t mechanically fastened to the walls will pull back within months. What you can safely do yourself is inspect: go under the house with a good flashlight, look for tears, check the wall fasteners, and note where any water is pooling. What we’d recommend against: buying a roll of poly at the hardware store, laying it over the old failed liner, and calling it done. That traps moisture between the two layers and makes the original problem worse. If you’ve got the time and don’t mind crawling around under your house, replacing a small, simple liner is possible. But if the space is tight, the old liner is failed, or you’re seeing mold on the joists, call us at (747) 837-5834 and we’ll get it assessed and fixed properly.

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