Johns Manville Attic Insulation Nationwide

Johns Manville Attic Insulation: The Los Angeles Owner’s Guide

We stock and install Johns Manville attic insulation products across Los Angeles, with most residential retrofits running between $1.80 and $3.20 per square foot installed depending on the assembly depth and whether the attic needs air sealing first. Same-day installation is available for standard R-30 through R-49 blown fiberglass jobs when we have your square footage and access details by 10 a.m. Most Los Angeles homeowners discover their Johns Manville insulation is failing when the second floor of their home won’t cool below 78 degrees even after sunset, or when they pull back a section in the attic and find batt strips that have compressed to less than half their labeled thickness.

Call (628) 226-1097

Which Johns Manville Models This Applies To

Johns Manville produces several attic insulation lines that circulate in the Los Angeles market, and the part you need depends on what was originally installed and what’s still performing. The Climate Pro blown fiberglass series, labeled R-30, R-38, or R-49 on the bag, is the most common retrofit product we see in homes built between 1985 and 2010 across neighborhoods like Leimert Park, Baldwin Hills, and the older ranch tracts of the San Fernando Valley. The batts, sold as Kraft-faced or unfaced R-13 through R-38, were frequently used in original construction and in knee-wall assemblies where blown product won’t hold position.

To identify what you have, check the paper facing on batts for the JM logo and density rating, or look for the white-and-green bag remnants if blown fiberglass was used. The critical compatibility gotcha in Los Angeles: Johns Manville blown fiberglass at R-38 requires a minimum settled depth of 12 inches, but many installers in the 2000s blew to 10 inches and called it done. That 2-inch deficit translates to a real performance loss you can feel in August. We source Johns Manville materials through standard distribution, same as Owens Corning, Knauf, and Rockwool, and we do not represent ourselves as affiliated with Johns Manville.

Signs Your Johns Manville Attic Insulation Is Failing

• Uneven temperature between floors. The upstairs runs 8 to 14 degrees warmer than downstairs by late afternoon. This happens when blown fiberglass has settled or migrated away from the eaves, creating thermal bypasses that your ductwork can’t overcome.
• Compressed or displaced batts. Original R-30 batts measuring 9.5 inches when installed have compressed to 4 inches or less after years of storage traffic, rodent nesting, or moisture weight. Once compressed, the R-value drops proportionally; a 50% compression roughly halves the thermal resistance.
• Visible dark staining on insulation surface. Gray or black streaks indicate filtered air leakage, the signature of an unsealed attic floor. Your conditioned air is escaping through cracks, carrying dust that deposits on the fiberglass. The insulation isn’t the problem; the air leaks are, and new insulation laid over the stains will fail the same way.
• Ice damming or moisture on roof sheathing in winter. Even Los Angeles sees enough cool nights for this: warm, moist interior air hits cold sheathing and condenses. Johns Manville fiberglass doesn’t rot, but the surrounding framing does, and the wet insulation loses effectiveness until it dries.
• Energy bills climbing year over year with no rate change. A 20% increase over three years, with usage patterns held constant, points to insulation performance degradation. We verify this with a blower-door test, a pressurization reading that shows, in one number, how much air your building envelope is losing.

Before

After

Replacement Cost & What’s Included

In Los Angeles, a full Johns Manville attic insulation replacement on a 1,200 to 2,000 square foot home typically runs $2,200 to $4,800 installed. That range breaks down as follows: removal and disposal of existing material, $0.60 to $1.10 per square foot; air sealing of top plates, can lights, and penetrations, $0.40 to $0.80 per square foot; and new Johns Manville Climate Pro blown fiberglass at your target R-value, $0.80 to $1.30 per square foot. Homes with extensive rodent damage, asbestos-containing vermiculite, or inaccessible vaulted ceilings land at the upper end.

We don’t start work without a written price. Under Haven Standard Clause 1, you get a flat price, written scope, and written warranty before anyone lifts a tool. The 365-Day Done Right Promise applies to all completed work, and every job closes with a Documented Photo Record showing the sealed attic floor before insulation goes in and the finished depth after.

DIY or Call Us?

There’s no high-tension danger in handling fiberglass insulation, but there are genuine health and performance reasons to be careful. An owner can safely check attic depth with a ruler, photograph any labels or bag remnants, and verify that soffit vents aren’t blocked. What goes wrong fast: disturbing older material without testing for asbestos first, blowing new insulation over unsealed air leaks and paying for R-value you can’t use, and missing fire-blocking requirements around chimney chases or recessed cans that Los Angeles building code still enforces.

Wes Okafor and our crew have been measuring, air-sealing, and blowing attic assemblies across Los Angeles for over two decades. We run a blower-door test before any insulation goes in, because sealing the holes first, then measuring the R-value, in that order, is the only way to get a result you can document. Call (628) 226-1097 for a written estimate with no work obligation.

FAQs