Insulation Contractor FAQs

  • Introduction

    Insulation is a crucial part of the building construction or renovation process, and having the right insulation in a structure can increase comfort, reduce energy costs, and minimize your carbon footprint. Because insulation comes in a variety of materials and forms, it can be difficult to choose what’s right for your project. Understanding the basics of insulation materials, measurement, and installation can help you choose the right product and professional installer for your home or business.

  • What is an insulator?

    An insulator is a substance that doesn’t readily conduct electricity, heat, or sound. In construction, insulators help keep heated and cooled air from passing through walls, ceilings, and floors to control energy costs, so interiors stay warmer in the winter and cooler in the summer. Insulators may also be used to soundproof rooms or protect against electrical shocks.

  • What does asbestos insulation look like?

    The most common type of asbestos insulation is vermiculite. This lightweight material is typically silvery-gold or grayish-brown with a pebble-like appearance. However, asbestos insulation also comes in other forms, including sheet-like wraps for use on pipes and HVAC ducting, and lumpy or snow-like loose-fill insulation commonly installed in attics and wall cavities.

  • Is plastic an insulator?

    Yes. Plastics are poor conductors of heat and electrical currents, so they function well as insulators. This man-made material may serve as insulation in vinyl siding, and because it’s moldable, it’s commonly used for wrapping wires.

  • What does insulation do?

    Insulation minimizes the exchange of heat in a structure. It can improve a building’s comfort by keeping it warmer when outside temperatures are cold and cooler when outside temperatures rise. It can also improve the efficiency of HVAC systems to reduce heating and cooling costs.

  • Is insulation flammable?

    Whether insulation is flammable depends on its composition. Most common insulation materials are designed to be fireproof or fire-resistant, but there are some, including spray foam and cellulose, that are flammable. Insulation materials may also include paper or foil backings, which may be flammable and should be treated with a fire retardant.

  • How do you find out how much insulation you need?

    To determine how much insulation you’ll need for a project, measure the height and length of the exterior walls. Multiple those two numbers to determine the square footage for each wall and then add them together. Repeat the measurement process for windows and doors and subtract that from the total.

  • How do you cut insulation?

    Insulation that comes in batts or rolls needs to be cut. To do so, lay your insulation on a flat surface and use a small board as a straight edge. Using a utility knife with the blade fully extended, cut each roll to the dimensions you need.

  • What is insulation made of?

    Insulation may be composed of a variety of materials, including:

    • Fiberglass
    • Cellulose
    • Polyurethane
    • Polystyrene
    • Polyisocyanurate
    • Plastic fibers
    • Natural fibers
    • Mineral wool (rock or slag)
    • Foam beads
    • Foam boards or blocks
    • Polyethylene bubbles

  • How much does insulation cost?

    The cost of insulation is typically expressed per board foot, which is one square foot by one inch thick. Costs generally increase along with R-value and vary according to material type:

    • Radiant: $0.20 to $1
    • Rigid: $0.25 to $1
    • Batting: $0.30 to $1.50
    • Spray foam: $0.50 to $2
    • Blown-in: $1 to $2

  • What is thermal insulation?

    Thermal insulation refers to the process of preventing heat from transferring between objects or spaces through the use of a nonconductive barrier. Thermal insulation may also refer to the materials used as a barrier to prevent heat transfer between objects or places. 

  • Is fiberglass insulation flammable?

    No. Fiberglass is noncombustible and will melt when exposed to flames instead of burning. However, if the fiberglass insulation is formed into batts, it may include a Kraft paper or foil backing, which is flammable. 

  • Is Styrofoam a good insulator?

    Yes. Styrofoam, which is the trademarked name for polystyrene foam, is a good insulator. Because it traps air in small pockets, it effectively reduces the flow of heat. Styrofoam is often used to insulate the wall cavities of buildings. 

  • How do you tell the difference between cellulose and asbestos insulation?

    Cellulose and asbestos insulation often look similar, and the naked eye typically can't differentiate between the two materials. However, asbestos was commonly used as an insulator between the early 1940s and late 1980s, so if a building was constructed before 1940, or after 1990, the insulation is probably not asbestos.

  • How do you insulate outdoor water pipes?

    Outdoor water pipes may be insulated by using foam pipe sleeves or strips of pipe wrap. Insulation may also be placed in gaps created where water pipes penetrate a structure’s exterior walls. Faucet covers may provide additional protection for outdoor spigots.

  • What is an electrical insulator?

    An electrical insulator is a material that doesn’t let electrical impulses pass freely through it. Electrical insulators may be used to coat wires or cables to prevent electrical shocks. Effective electrical insulators include:

    • Rubber
    • Glass
    • Air
    • Plastic
    • Fiberglass
    • Porcelain
    • Quartz

  • Does fiberglass insulation burn?

    No. Fiberglass is nonflammable and doesn’t burn. If it’s exposed to an open flame or reaches a high enough temperature, it will simply melt. However, if backing materials such as foil or paper are attached to fiberglass insulation, they may burn.

  • What does R-value mean in insulation?

    The R-value of an insulating material refers to how well it prevents the flow of heat. The higher the R-value, the more effective a material is as an insulator. The R-value of insulation is typically expressed per inch of material thickness.

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