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Perlite insulation is a type of insulation made from volcanic rock. The rocks used to make perlite insulation have a high water content, which helps to create large quantities of air pockets within the rock when heated. These air cells make perlite an excellent insulator, giving it a high level of thermal resistance. In its most basic state, this material has a white chalky appearance and typically comes in the form of small pellets or granules.
Many builders and homeowners rely on perlite insulation to block unwanted airflow in walls, roofs, and foundations. This material is particularly popular as a form of loose-fill attic insulation. In addition to improving thermal resistance, perlite insulation also blocks unwanted noise to keep the inside of the home quieter. Unlike alternative forms of insulation, perlite also offers a relatively high level of fire resistance, and helps to slow the spread of heat and flames.
The high thermal resistance of perlite insulation makes it an excellent option for those looking to improve energy efficiency ratings in a home or building. Properly-installed insulation can cut heating and cooling costs and help protect the environment by reducing wasted energy. Effective insulation also improves the overall comfort of occupants and helps to eliminate cold drafts.
Perlite insulation can be found in many forms. Perlite granules may be added to concrete mixtures to improve the insulation of the concrete as it dries. It may also be used as a loose-fill material within the cavities in masonry blocks. Some manufacturers even press perlite into sheets so that it can be used in place of rigid foam insulation in walls or ceilings. Perlite may even be added into the asphalt mixture on a standard asphalt roof to improve insulation and fire resistance.
Outside of the construction industry, perlite insulation is often used in very low-temperature applications. It may be used to line refrigerators for food storage, or to build trucks used for shipping frozen goods. Perlite also serves as a popular insulator in cryogenics and medical research applications.
One of the primary advantages to perlite is its light weight, which allows it to be used in a wide variety of applications. Unlike some other popular insulators, perlite contains only inorganic materials. This means it is resistant to moisture, rot, and even termites and other pests. Perlite's natural moisture resistance eliminates problems with mold and mildew that can often plague other types of insulation.