Johns Manville is a major U.S. insulation manufacturer owned by Berkshire Hathaway

Johns Manville manufactures fiberglass, mineral wool, and foam insulation products sold through building supply retailers and contractors. The company is based in Denver, Colorado, and has been making insulation since 1858. Berkshire Hathaway acquired it in 2001. You will encounter Johns Manville products when you shop for insulation by R-value, material type, or process — attic, wall cavity, basement, or pipe insulation.

The company does not sell directly to homeowners. You buy Johns Manville insulation through home improvement retailers like Home Depot and Lowe's, or through contractors who source materials themselves. The products carry the Johns Manville brand name on the packaging, so you can identify them at the point of purchase.

Johns Manville competes with Owens Corning, Knauf, CertainTeed, and regional manufacturers. The choice between brands often comes down to what your local retailers stock, what your contractor prefers to install, and the specific R-value and form you need for your project.

Key Takeaways

  • Johns Manville makes fiberglass batts and rolls, mineral wool products, and spray foam insulation in a range of R-values for different building applications.
  • You purchase Johns Manville insulation through retail stores or contractors, not directly from the manufacturer.
  • The company's products are priced competitively with other national brands and vary by material type, thickness, and whether they include a vapor barrier.
  • Johns Manville insulation is made in multiple U.S. facilities and meets building codes and fire safety standards in all 50 states.

Main product lines and what they are used for

Johns Manville's largest product category is fiberglass batts and rolls. These are blankets of compressed fiberglass with a kraft paper or foil facing on one side. They come in standard widths (16 inches or 24 inches) to fit between wall studs and ceiling joists. R-values range from R-3.2 to R-38 depending on thickness. Homeowners and contractors use these for attic insulation, wall cavities, and basement rim joists.

The company also makes mineral wool insulation, which is made from rock or slag and comes in batts, rolls, and rigid boards. Mineral wool has a higher melting point than fiberglass, so it is often chosen for fire-rated applications and areas near chimneys or furnaces. It also provides some sound dampening. Mineral wool costs more per square foot than fiberglass.

Johns Manville manufactures spray foam insulation under the brand name Corbond. This is a two-part polyurethane foam that expands when sprayed into wall cavities, attics, or crawl spaces. Spray foam seals air leaks as it expands and achieves higher R-values per inch than batts or rolls. Installation requires a licensed contractor with spray equipment.

The company also produces rigid foam boards (extruded polystyrene and polyisocyanurate) for basement walls, foundation insulation, and exterior sheathing. These are sold in standard sheet sizes and thicknesses.

R-value options and how they compare to other brands

Johns Manville fiberglass batts are available in R-values from R-3.2 to R-38. An R-3.2 batt is roughly 1 inch thick and is used for pipe insulation or supplemental coverage. An R-38 batt is about 12 inches thick and is standard for attic insulation in cold climates. The R-value you need depends on your climate zone and whether you are insulating an attic, wall, or basement.

Owens Corning and CertainTeed offer the same R-value range in fiberglass batts, so the choice between brands usually comes down to availability and price at your local retailer. Mineral wool batts from Johns Manville and competitors like Rockwool achieve the same R-values in slightly thinner profiles, which can be useful in tight spaces.

Spray foam insulation from Johns Manville (Corbond) achieves R-6 to R-7 per inch, compared to R-3.2 to R-3.8 per inch for fiberglass. This means spray foam takes up less space to reach the same R-value, but costs significantly more and requires professional installation.

Facing options and vapor barriers

Johns Manville fiberglass batts come with three facing choices: kraft paper, foil, or unfaced. Kraft paper facing is a vapor retarder that slows moisture movement and is standard in most climates. Foil facing reflects radiant heat and is used in hot climates or where you want additional moisture protection. Unfaced batts have no facing and are used when you are installing a separate vapor barrier or in applications where moisture is not a concern.

The facing you choose depends on your climate, whether the wall or attic already has a vapor barrier, and building code requirements in your area. Installing the wrong facing can trap moisture and lead to mold or rot. If you are unsure, ask your contractor or check your local building code.

Price range and where to buy

Johns Manville fiberglass batts cost between $0.30 and $0.60 per square foot, depending on R-value and facing. A standard roll of R-19 unfaced fiberglass for a 16-inch cavity costs roughly $40 to $60 at Home Depot or Lowe's. Mineral wool batts cost 20 to 40 percent more. Spray foam costs $1.00 to $2.00 per square foot installed, making it the most expensive option per square foot.

You can purchase Johns Manville insulation at Home Depot, Lowe's, Menards, and local building supply stores. Prices vary by location and current promotions. Contractors often buy directly from wholesale distributors and may pass on volume discounts to you. If you are hiring a contractor, ask whether they source Johns Manville or another brand and whether the price includes labor and disposal of old insulation.

Manufacturing locations and certifications

Johns Manville operates manufacturing plants in multiple U.S. states, including Colorado, Georgia, Kansas, and others. The company publishes a list of plant locations on its website if you want to know where a specific product was made.

All Johns Manville insulation products meet or exceed the fire safety standards set by the American Society for Testing and Materials (ASTM) and comply with building codes in all 50 states. Fiberglass and mineral wool batts are non-combustible or fire-resistant. Spray foam is treated with fire retardants. Check the product label or data sheet for the specific fire rating if you are installing near a furnace, water heater, or chimney.

How Johns Manville compares to Owens Corning and other competitors

Owens Corning is the largest insulation manufacturer in the United States and offers a nearly identical product range to Johns Manville: fiberglass batts, mineral wool, and spray foam. Prices and R-values are comparable. The main difference is brand availability — some retailers stock more Owens Corning, others stock more Johns Manville, depending on regional distribution agreements.

Knauf and CertainTeed also make fiberglass and mineral wool insulation at similar price points. Rockwool specializes in mineral wool and is often chosen for fire-rated or sound-dampening applications. Spray foam is available from multiple manufacturers, including Corbond (Johns Manville), Icynene, and regional contractors who use generic polyurethane formulations.

The choice between brands rarely matters as much as choosing the right material type and R-value for your climate and process. If your contractor or retailer recommends one brand over another, ask why — it may be because of local availability, their experience with installation, or a specific product feature you need.

Frequently Asked Questions

Is Johns Manville insulation safe to handle without a mask?

Fiberglass and mineral wool insulation can irritate skin and lungs if fibers are inhaled. Wear a dust mask, long sleeves, and gloves when handling or installing batts or rolls. Spray foam should only be installed by a licensed contractor wearing protective equipment. Once insulation is installed and covered, it poses no ongoing risk.

Can I install Johns Manville batts myself, or do I need a contractor?

Fiberglass and mineral wool batts can be installed by homeowners with basic tools and safety precautions. Spray foam requires professional equipment and licensing. If you are unsure about vapor barriers, facing direction, or building code requirements, hire a contractor to avoid costly mistakes.

What is the difference between kraft paper and foil facing?

Kraft paper is a standard vapor retarder used in most climates. Foil reflects radiant heat and provides additional moisture protection in hot or humid climates. Check your local building code or ask your contractor which facing is appropriate for your climate zone and wall assembly.

Does Johns Manville insulation contain asbestos?

Modern Johns Manville insulation products do not contain asbestos. The company stopped using asbestos in the 1970s. If you are removing old insulation from a home built before 1980, have it tested for asbestos before disturbing it.

How long does Johns Manville insulation last?

Fiberglass and mineral wool batts last 80 to 100 years if kept dry and undisturbed. Spray foam lasts 80 years or longer. Insulation degrades if it gets wet, compressed, or exposed to pests. Proper installation and ventilation extend the life of any insulation product.