Johns Manville Vapor Barrier Installation: The West Hollywood Owner’s Guide
Johns Manville vapor barrier installation in West Hollywood typically runs $1,800 to $3,400 for a standard crawl space, and yes, we can usually get it done same week. Most owners discover their vapor barrier has failed when they smell musty air rising through the floorboards or spot moisture beading on foundation walls. You’re not looking for a lecture on moisture science here. You’re looking for a crew that will show up, lay the right Johns Manville product correctly, and stand behind the work for life. That’s what we do.
Key Takeaways:
- We stock Johns Manville vapor barrier material in 6-mil, 10-mil, and 20-mil thicknesses and can have your exact spec on the truck the day we come out
- Installed pricing for West Hollywood crawl spaces runs $1,800 to $3,400 depending on square footage, access, and whether old barrier removal is needed
- Every installation is covered by our lifetime Done Right Promise, and every call is answered by a live person, 24/7
Which Johns Manville Models This Applies To
Johns Manville manufactures vapor barriers under a few different product lines, and the naming can trip people up. You’ll see it sold as JM VaporBlock, JM Duratuff, or simply listed as a poly vapor retarder. The practical distinction comes down to thickness: 6-mil is the minimum we’ll install in a West Hollywood crawl space, 10-mil handles most residential jobs, and 20-mil is what you want under a concrete slab or in a crawl space that doubles as storage. If you have the original packaging, look for the mil thickness printed on the label. If you don’t, measure the torn section with a micrometer or just call us and we’ll identify it on site.
We’re an independent service provider, not affiliated with Johns Manville, which means we recommend the product that actually fits your crawl space rather than whatever a franchise agreement tells us to push. That said, Johns Manville poly has held up better in California crawl spaces than most aftermarket rolls we’ve seen, largely because the virgin resin blend resists the kind of punctures you get from gravel and construction debris. We also stock Reflectix for reflective insulation needs, so if your project calls for a combination approach, we’re not running back to the supply house mid-job.
Signs Your Johns Manville Vapor Barrier Installation Is Failing
- Musty or earthy smell drifting up through the floor. Moisture is bypassing the barrier somewhere, usually at a seam or against a foundation wall where the poly wasn’t lapped far enough up and sealed.
- Visible rips, tears, or gaps along the edges. Rats and mice chew through poly, and in older West Hollywood homes near the hills, rodents are common. Once there’s a hole, moisture moves through freely.
- Standing water pooling on top of the barrier. This usually means the barrier was laid without proper grading or a sump pump in a high-water-table crawl space. A barrier can’t work if water collects on top of it.
- Condensation on ductwork or floor joists. If the barrier isn’t sealed at seams and edges, humid air still reaches the wood above, and condensation follows.
- The barrier has pulled away from foundation walls. In West Hollywood’s seismic activity, even minor ground movement shifts crawl space soil, and unanchored poly pulls back from the walls, exposing the exact perimeter where moisture enters.
Replacement Cost & What’s Included
For West Hollywood homes, here’s what we quote and what’s actually included.
| Scope | Installed Price Range |
|---|---|
| Small crawl space (under 800 sq ft), 10-mil | $1,800-$2,200 |
| Standard crawl space (800-1,500 sq ft), 10-mil | $2,200-$2,800 |
| Large or low-clearance crawl space, 20-mil | $2,800-$3,400 |
| Old barrier removal and disposal (if needed) | Included |
| Seam sealing, pipe boot sealing, perimeter fastening | Included |
| Lifetime Done Right Promise workmanship warranty | Included |
What drives the price: square footage, how much clearance the crawl space has (low-clearance work is slower and harder on the body), whether old barrier has to be cut out and hauled away, and whether we’re also re-taping duct joints or sealing rim joist gaps while we’re down there. We give upfront pricing before we start, not after we’ve finished. You’ll know the number when you approve the job.
DIY or Call Us?
Laying vapor barrier poly in a crawl space isn’t the most dangerous work we do, but it’s also not a Saturday project most West Hollywood homeowners enjoy. If you want to inspect before calling, you can check the seams with a flashlight and look for standing water, rodent droppings, or visible tears. That’s useful information for us. But installing Johns Manville vapor barrier correctly means working in tight, dark, sometimes wet conditions, overlapping seams by at least 12 inches, sealing every seam, cutting around every pier and pipe, and running the poly up the foundation walls at least 6 to 12 inches. Get one seam wrong and the whole system underperforms.
We do the job right the first time, because coming back to fix it isn’t good for either of us. If you want to talk through what you’re seeing, call (213) 527-4062 and you’ll get a live person. Walt Brenner or one of the crew can walk you through it.
FAQs
A properly installed Johns Manville 10-mil or 20-mil barrier typically lasts 15 to 20 years in West Hollywood conditions, though rodent damage and ground movement can shorten that. Our lifetime Done Right Promise covers the workmanship for as long as you own the home. Call (213) 527-4062 to have your current barrier inspected.
Yes, small tears and seam separations can sometimes be patched with the correct seam tape and additional poly, typically for a few hundred dollars rather than a full replacement. The catch is that if the barrier has multiple perforations from rodent traffic, patching becomes the more expensive option over time. Call us and we’ll tell you straight which one applies to your crawl space.
A standard West Hollywood crawl space vapor barrier installation takes one workday, including removal of old material where needed. Larger homes with low clearance or extensive pier work can take two days, and we’ll tell you up front before we schedule.
We keep 6-mil, 10-mil, and 20-mil Johns Manville poly on the truck along with seam tape, pipe boots, and fasteners, so we can typically install the same day we diagnose. If your project calls for an unusual width or a slab-grade product, we can have it in hand within a few days.
Written by Walt Brenner, Owner, Walt’s Insulation at Walt’s Insulation, serving West Hollywood and nearby areas.