Johns Manville Crawl Space Encapsulation & Vapor Barrier Nationwide

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

Johns Manville crawl space encapsulation and vapor barrier work in Inglewood typically costs between $1,800 and $6,500 depending on square footage, access clearance, and whether we’re doing a clean install or a retrofit around existing ductwork and piers. Most jobs are completed in a single visit, and we’re an independent Johns Manville service provider, which means we work on the materials already in your home rather than pushing a rip-and-replace you may not need. If you’re seeing standing water, mold on floor joists, or a musty smell rising into your living space, this page explains exactly what we’ll do about it. Call (424) 622-5846 and a live person answers, 24/7.

Call (424) 622-5846

This page is for Inglewood homeowners who already have Johns Manville insulation or vapor barrier products in their crawl space, or who are considering them for a new encapsulation project. We’ll cover how these materials behave in our coastal-inland climate, what fails and why, and what an honest fix costs.

Key Takeaways

• We service Johns Manville crawl space systems as an independent provider, never voiding your manufacturer coverage.
• Inglewood’s marine-layer humidity and clay-heavy soil create specific problems for crawl space assemblies.
• Most Johns Manville encapsulation jobs finish in one day and carry our 90-Day Done Right Promise.
• We also work with Reflectix for radiant barrier needs in the same crawl space project.

How Johns Manville Products Fail - and How We Fix Them

Johns Manville makes solid insulation products, but no material is immune to what a Southern California crawl space throws at it. Here are the failure patterns Neil Ashford and our crew see most often in Inglewood homes, from Morningside Park over to the blocks near SoFi Stadium.

• Johns Manville ComfortTherm batts wicking moisture from exposed earth. ComfortTherm is a kraft-faced batt meant for wall cavities, but in older Inglewood homes we find it stapled under floor joists with the facing pointing the wrong direction. In a vented crawl space, the kraft paper acts like a sponge. Once it saturates, it sags, loses R-value, and starts feeding mold on the subfloor above. Our fix is removal, then installing a continuous Johns Manville vapor barrier on the ground and switching to an unfaced or encapsulated product rated for below-floor use.
• Perforated radiant barrier foil degrading in high-humidity crawl spaces. Some Inglewood homes built in the 1990s and early 2000s have perforated reflective insulation stapled under the floor. The perforations that allow moisture to pass through in normal conditions become a liability when the crawl space floods seasonally. We see the foil delaminating from its scrim and flaking onto the soil. We remove it and assess whether the home needs a vapor barrier retrofit with a Johns Manville poly liner or a full encapsulation.
• Johns Manville AP Foil-Faced polyiso board absorbing water at cut edges. When rigid polyiso board is cut to fit between floor joists, the exposed cut edges are open-cell foam. In an Inglewood crawl space with 70%+ relative humidity much of the year, those edges slowly take on moisture, and the board’s R-value drops from roughly R-6 per inch to far less. We always seal cut edges with compatible tape during installation, and we check existing boards for soft spots before recommending replacement.
• Missing or torn 6-mil ground liner letting soil moisture load the entire assembly. The single most common issue in Inglewood crawl spaces is no ground vapor barrier at all, or one that’s been torn by plumbers, electricians, or rodents. With clay-heavy soil holding water through the rainy season, an unlined crawl space can push gallons of moisture into your floor system daily. We install or replace the liner as the foundation of any Johns Manville encapsulation job, running it up piers and sealing seams.
• Compressed Johns Manville fiberglass losing its loft from repeated foot traffic. In crawl spaces that double as storage, we see batts crushed flat under boxes, Christmas decorations, and old furniture. A compressed R-30 batt performs closer to R-12. We remove the damaged sections, and when the homeowner wants to keep using the space for storage, we recommend either raised decking or transitioning to a closed-cell spray foam that holds its shape.

Our Johns Manville Crawl Space Encapsulation & Vapor Barrier Process

1. 1
   Inspection and moisture mapping. We start by measuring relative humidity at multiple points, checking joist moisture content with a meter, and mapping where water enters. In Inglewood, that often means a low corner near a downspout or a foundation crack on the home’s uphill side.
2. 2
   Cleanout and prep. We remove debris, old insulation if it’s compromised, and any rodent nesting material. We also trim back any plastic sheeting that’s blocking vents or wrapping ductwork.
3. 3
   Ground vapor barrier installation. We lay a Johns Manville poly liner across the soil, overlapping seams by 12 inches and sealing them with contractor-grade tape. We run the liner up foundation walls and piers, securing it with mechanical fasteners so it won’t sag.
4. 4
   Encapsulation or insulation decisions. If the home calls for a full encapsulation, we seal vents, insulate the perimeter walls with Johns Manville rigid board or closed-cell spray foam, and condition the space. If it’s a vapor barrier retrofit, we install fresh below-floor insulation rated for the application.
5. 5
   Air sealing and pest exclusion. We seal rim joist bays, pipe penetrations, and any gap larger than a pencil where rodents enter. This step alone cuts the musty smell most Inglewood homeowners complain about.
6. 6
   Verification and cleanup. We re-check humidity, confirm the liner is secure, and photograph the finished work for your records. Then we walk you through everything we did, and the 90-Day Done Right Promise goes into effect before we leave the driveway.

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

Honest numbers for Inglewood homes, based on the jobs we’ve completed here over the last decade:

• Ground vapor barrier only, 1,000 sq ft crawl space: $1,800 to $3,200
• Full encapsulation with vapor barrier, wall insulation, and vent sealing: $4,500 to $6,500
• Insulation removal and replacement above an existing vapor barrier: $1,400 to $2,800
• Edge sealing and humidity correction for a partially finished crawl space: $900 to $1,700

The price moves based on access clearance (some Inglewood crawl spaces under older bungalows are 18 inches or less), whether we need to remove failed insulation, and the condition of existing ductwork. The 5% Senior & Veteran discount applies to every quote, and estimates are free. Call (424) 622-5846 and we’ll give you an upfront number, not a range that doubles later.

Why Inglewood Homeowners Call Warmline Insulation Co. for Johns Manville Work

We’ve been crawling under Inglewood houses since 2011, and we’ve seen what happens when the wrong contractor touches a Johns Manville system. The wrong tape on a vapor barrier seam, the wrong facing direction on a batt, a vent left open during encapsulation - all of it shows up on your energy bill or your subfloor within a season. The work should speak for itself - and so should your energy bill. Our techs are background-checked, uniformed, and trained on Johns Manville materials specifically. When a home also needs Reflectix radiant barrier for a hot attic above the crawl space, we handle that too. Most jobs are completed in a single visit, and if anything isn’t right, our 90-Day Done Right Promise means we come back and make it right at no charge. Neil Ashford has been diagnosing air-sealing problems other contractors walk right past for the better part of two decades.

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