Johns Manville Crawl Space Encapsulation & Vapor Barrier in Round Rock: What to Know First
We provide independent Johns Manville crawl space encapsulation and vapor barrier service in Round Rock, with most jobs scheduled within 48 hours and completed in a single day. Our written price lands before any work starts - no exceptions - and every crawl space job closes with a Documented Photo Record you keep. If you’re seeing musty odors, sagging insulation, or standing water under your Johns Manville-protected crawl space, call (737) 259-7528. We’ll read your situation, name a flat price, and show up when we say we will.
How Johns Manville Products Fail - and How We Fix Them
- JM Formaldehyde-free fiberglass batts losing R-value in crawl floors. The Kraft-faced batts common in 2018-2022 Round Rock builds absorb ground moisture through torn facing, then compress from 6.25 inches to under 4 inches. We remove the degraded material, install a 6-mil or thicker polyethylene vapor barrier sealed at seams and piers, and replace with JM Spider or blown-in fiberglass that doesn’t rely on paper facing for its thermal rating.
- JM AP Foil-faced polyiso boards delaminating in vented crawl spaces. The foil facing acts as a vapor barrier on the wrong side when summer humidity hits 80% in Round Rock’s clay-heavy soils. Condensation forms between foil and concrete block walls, bubbling the adhesive. We strip the failed boards, apply closed-cell spray foam or a proper encapsulation liner to the walls, and reinstall only where the assembly is conditioned.
- JM ComfortTherm encapsulated batts wicking at staple penetrations. The plastic sleeve is punctured during sloppy installation, letting Williamson County’s alkaline groundwater wick upward through the slit. We pull the compromised runs, seal the subfloor with a continuous vapor barrier, and reinstall using support wire or friction fit - no staples through the sleeve.
- JM blow-in loose-fill settling over unsealed top plates in crawl-to-attic chases. The material migrates into the crawl space through gaps around plumbing and wiring, creating bare spots above and piles below. We blower-door test first - seal the leaks first. The insulation has nowhere to go until you do - then redistribute or supplement the blown-in.
- JM Linacoustic RC duct liner degrading in high-humidity crawl environments. The coated airstream surface breaks down when relative humidity stays above 70% for weeks, which happens in Round Rock spring and fall when homeowners forget to run their HVAC fan. We assess whether the ductwork belongs in the crawl at all; when encapsulation isn’t enough, we relocate or replace with JM ToughGard or metal ducting.
Our Johns Manville Crawl Space Encapsulation & Vapor Barrier Process

- 1
Call and scope. A live person answers 24/7. We ask about your home’s age, crawl access size, and what you’re seeing - mold, odors, cold floors, or energy spikes. We schedule a site visit, usually within 48 hours.
- 2
Site inspection and blower-door test. Wes or a named technician arrives in uniform, photographs the existing condition, and runs a blower-door test if the crawl connects to conditioned space. We mark air leaks, measure moisture content in wood framing, and identify which Johns Manville products are in place.
- 3
Written price and material spec. You get a flat price, a written scope of work, and a written warranty before anyone lifts a tool. Haven Standard Clause 1. If you have another estimate, we’ll read it with you - Free Second Opinion.
- 4
Air sealing first, then encapsulation. We seal rim joists, sill plates, and penetrations with appropriate sealant or foam. Then we install the vapor barrier or full encapsulation system - 6-mil minimum, 12-mil or 20-mil for storage-grade crawls, sealed to walls and piers, taped at seams.
- 5
Insulation replacement and conditioning. Only after sealing do we install or replace Johns Manville insulation products suited to the now-controlled environment. We document R-values and placement in the photo record.
- 6
Post-install documentation. You receive the Documented Photo Record, any before-and-after blower-door numbers, and the written warranty. The 365-Day Done Right Promise is active from that moment.
What Johns Manville Crawl Space Encapsulation & Vapor Barrier Costs in Round Rock
Most crawl space vapor barrier installations in Round Rock run between $2,800 and $5,200 for a 1,200-2,000 square foot footprint. Full encapsulation with dehumidification typically falls between $5,500 and $11,000. What moves the price:
- Access difficulty. A 24-inch crawl height in an older Fern Bluff home takes longer than a 36-inch new build in Behrens Ranch.
- Existing material removal. Saturated JM batts or mold-affected polyiso add labor and disposal.
- Conditioning requirements. Sealing vents, adding a dehumidifier, or routing HVAC into the crawl space.
- Vapor barrier thickness. 6-mil for basic moisture control; 12-mil or 20-mil if you plan to store anything down there.
Call (737) 259-7528 for a written estimate - there’s no charge, and we’ll read any competing quote with you.
Why Round Rock Homeowners Call Topside Attic Insulation Round Rock for Johns Manville Work

We’ve been independently owned and operated under The Haven Standard since 2016, and we’ve sealed and insulated over 9,000 homes - every one with a written price first and a documented record at the end. Our technicians are background-checked and uniformed; you get a name and a text when they’re on the way. We work with Johns Manville, Reflectix, Owens Corning, Knauf, and other major brands, so we’re not locked into pushing one product line that doesn’t fit your situation. Wes Okafor built this operation on sequencing: test, seal, insulate, document. That discipline matters especially in crawl spaces, where the wrong order traps moisture against structure and makes everything worse.
FAQs
No - our work as an independent Johns Manville service provider doesn’t void material warranties, though coverage for the original product remains with Johns Manville’s terms. We document what we find and what we install so any future warranty claim has clear records. If you’re unsure about your specific product’s warranty status, we can review the installation date and product line during our estimate. Call (737) 259-7528 to schedule.
Most inspections are scheduled within 48 hours, and encapsulation or vapor barrier work typically starts within a week of estimate approval. Emergency situations - standing water, active mold bloom, or compromised structural members - get prioritized. A live person answers our line 24/7 to assess urgency. Call (737) 259-7528.
Repair makes sense when the vapor barrier is mostly intact and the issue is localized - a torn section, one failed batt run, or a single leak point. Full encapsulation is the better investment when you’re seeing systemic moisture, multiple product failures, or energy bills climbing without explanation. We’ll show you both paths in the written estimate with flat prices for each. Call (737) 259-7528 for an exact recommendation on your crawl space.
We carry standard Johns Manville vapor barrier materials, seam tape, and compatible fasteners on our Round Rock trucks. Specialty items - 20-mil liner in non-standard widths, JM Spider custom blends, or specific foam board thicknesses - typically arrive within 2-3 business days from regional distribution. We never start work until all materials are on-site; no partial jobs left open to Round Rock humidity.
You get the numbers. On jobs where the crawl space connects to conditioned space, we run before-and-after blower-door tests - a pressurization reading that shows, in one number, how much air your building envelope was losing. We also photograph every stage and deliver a Documented Photo Record. Under our 365-Day Done Right Promise, if moisture returns or the seal fails, we make it right. That promise is in writing before we start.
Written by Wes Okafor, Owner, Topside Attic Insulation Round Rock at Topside Attic Insulation Round Rock, serving Round Rock and nearby areas.