Rigid roof insulation is the term for a number of different insulators grouped together due to their predefined shape and panelized construction. Many different types of rigid roof insulation of varying materials and construction types exist. These insulators are made of materials ranging from rock to polystyrene. In most cases, these insulators come in precut panels called ‘batts,’ but it is generally very easy to recut them to fit a project of any size. In addition to roofs, rigid insulation may be found in the walls and ceilings of a building.
In general, people prefer using rigid roof insulation to other types for three reasons. They provide more insulation, based on capacity per square inch (square meter), than other forms. They resist rot, water damage and pest infestation better than other materials. Even natural rigid roof insulation has received extensive processing in order to make it a viable insulator, and this processing makes it resistant to many natural age effects. Lastly, it is typically much easier to install than soft or blown insulation.
There are a wide variety of different types of rigid roof insulation, but several more common types exist. Wood fiber insulation is common in buildings that have flat roofs. These panels are made of a pressed wood fiber, often a cane or vegetable byproduct, that is coated with asphalt. The protective value of these panels is very high, but their insulating factor is low.
Perlite and gypsum board are both made of rock. These materials are very strong, but will shatter or crumble under enough pressure. Both of these types of rigid roof insulation are typically implanted with glass and asphalt, although they are occasionally used in their natural form. Perlite is generally used on its own, but gypsum board is typically paired with a synthetic insulator both to improve its structure and to provide additional insulation.
Cellular glass boards are made of a mixture of glass and several other materials. Crushed glass and several binding chemicals are heated until the glass melts and mixes with the rest of the materials. When it cools, the glass is a strong and lightweight form of rigid roof insulation that resists cracking.
The last common type of rigid roof insulation is polystyrene. There are dozens of different types of polystyrene insulation, each with its own properties. In general, this material is inexpensive, extremely light and insulates as well or better than any other insulation. These materials often have a layer of aluminum foil on one side that helps reflect heat. This small addition improves polystyrene's insulation qualities.