Johns Manville Radiant Barrier Installation Nationwide

Johns Manville Radiant Barrier Installation: The Union City Owner’s Guide

We stock and install Johns Manville-compatible radiant barrier systems in Union City homes, with most attic installations running between $1,800 and $3,400 depending on square footage and whether your attic floor needs air sealing first. Same-day installation is available when we have your measurements, and we carry JM AP Foil-Faced and reflective insulation rolls on our trucks for Union City and the Decoto corridor. Most homeowners realize their radiant barrier is failing when upstairs rooms stay hot past 9 p.m. despite the AC running, or when their summer PG&E bill jumps 20-30% year-over-year without rate changes.

Call (650) 381-1512

Which Johns Manville Models This Applies To

Johns Manville makes several radiant barrier products, and the part number matters for fit and fire rating. We most commonly install JM AP Foil-Faced Polyiso (R-6 to R-9.6 depending on thickness, 4×8 sheets or rolls), ComfortTherm reflective batt wraps, and the Formaldehyde-free kraft-faced radiant barrier used in vented attics across Alameda County. Check the foil stamp on your existing material: JM prints a lot number and ASTM C1289 compliance mark on the reflective face. If that stamp has worn off, measure the thickness with a tape measure, not a guess, polyiso comes in ½-inch, ¾-inch, and 1-inch nominal thicknesses, and the wrong thickness leaves a gap at the rafter bay that kills the barrier effect.

OEM Johns Manville material runs 15-20% more than quality aftermarket equivalents like Reflectix, which we also stock. For Union City homes under Title 24 compliance review, we typically specify JM or another brand with the same Class A fire rating and emissivity value below 0.05. The compatibility gotcha: JM’s polyiso uses a foil facing bonded with a specific adhesive that can delaminate in high attic humidity, common in Union City homes near the bay where marine air gets pulled into vented attics. If your existing JM barrier shows foil peeling at the edges, we match the replacement to the substrate, not just the reflectivity.

Signs Your Johns Manville Radiant Barrier Is Failing

• Hot ceiling patches at midday. The radiant barrier’s job is to reflect solar heat back toward the roof deck before it radiates into living space. When foil facing oxidizes or collects dust (common in Union City after dry winters with little rain to wash roof vents), emissivity rises above 0.05 and heat penetrates in discrete bands where the barrier has degraded.
• AC runs continuously from 2 p.m. to 7 p.m. in summer. This is the solar load window for west- and south-facing roofs in Union City. A functioning JM barrier should drop radiant heat gain by 95% or better. When it fails, your ducts in the attic superheat and the system never catches up.
• Foil facing visible from below is dull, not mirror-bright. Oxidation happens faster within two miles of the bay due to salt air intrusion. We see this regularly in homes near Alvarado-Niles Road where attic vents face prevailing winds. Dull foil means the surface emissivity has shifted; the material still looks intact but performs like plain cardboard.
• Insulation below the barrier is compressed or moisture-stained. A failed radiant barrier doesn’t just stop reflecting; it can trap condensation if the facing delaminates and creates a vapor barrier in the wrong place. We find this in Union City homes with original 1980s JM installations where the kraft facing has degraded and trapped winter moisture against the drywall.
• Your PG&E bill shows a summer kWh spike with no rate change or thermostat adjustment. We keep a spreadsheet of customer bills, and a failed radiant barrier typically shows as a 300-500 kWh jump June through September for a 1,500-square-foot home in Union City. That’s real money, usually $60-$120 per month.

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Replacement Cost & What’s Included

Most Johns Manville radiant barrier replacements in Union City run $1,800-$3,400 installed. Here’s how that breaks:

• $1,800-$2,400: Single-story home, 800-1,200 sq ft attic, standard gable roof, existing barrier removal and disposal included, JM AP Foil-Faced or equivalent Reflectix installed to rafter bays with mechanical fasteners.
• $2,400-$3,000: Two-story or complex roofline, 1,200-2,000 sq ft, requires attic floor air sealing of top plates and can lights before barrier goes in (Haven Standard: sealed first, then insulated).
• $3,000-$3,400: Large home or full re-insulation package, includes before-and-after blower-door test, documented photo record, and written warranty.

What drives the range: roof pitch (steeper = more labor), whether we need to move existing storage, and whether your attic has active air leaks that make the barrier pointless without sealing first. We won’t install over an unsealed floor. Every job gets a Written Price Before Any Work Starts, flat, with scope and warranty delivered before anyone lifts a tool. The 365-Day Done Right Promise covers labor and material defects. We are an independent service provider, not affiliated with Johns Manville.

DIY or Call Us?

Here’s what you can safely check yourself: verify the JM part stamp if visible, measure attic square footage at the floor (not the roof, which overstates by 20-30%), and photograph any foil delamination or moisture staining for our review. What goes wrong with DIY radiant barrier: working in 140°F attics without hydration planning, stepping through ceiling drywall at joist bays, and installing barrier with the reflective side facing the wrong direction (it happens more than you’d think). The R-value on the bag is what the material does in a lab. The number on your blower-door report is what your house actually does, and those two figures are not always friends.

We carry JM-compatible material on our trucks for Union City. Call (650) 381-1512 and we’ll read your situation with you, no charge.

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