Roof Insulation

Thermal insulation is a material used to reduce heat flow. It works best when installed outside of the structure to allow walls, floor, and ceiling to take on room temperature. By inhibiting the flow of heat energy, roof insulation helps to keep the home warm in the winter and cool in the summer. It conserves the energy by reducing the heat loss or gain of a structure.

Types of Roof Insulation

There are five forms of insulation for roofs: blankets, blown-in, foamed-in-place, rigid insulation, and reflective insulation systems. Blankets, made from mineral fibers, are made into the form batts or rolls. The widths are set according to standard spacing of wall studs and attic or floor joists. Blown-in insulation consists of loose-fill insulation, including loose fibers that are blown into building cavities or attics using special equipment. The blown-in material provides additional resistance to air infiltration. Foamed-in-place is polyurethane foam insulation that is sprayed into place. Polyurethane can help to reduce air leaks. Rigid insulation is made from plastic foams or fibrous materials. It is pressed into board-like forms to provide thermal and acoustical insulation. Reflective insulation systems are made from aluminum foils and they are most effective in reducing downward heat flow. They are typically located between roof rafters and tend to be more effective in hot rather than cold climates.

Thermal Insulation Materials

There are three common types of insulation materials: fiberglass, polymer, and cellulose. Fiberglas has R-values ranging from R-2.2 to 4.0 per inch, while Cellulose has an R-value of approximately 3.8 per inch. Polymer offers the highest insulating value per inch at R 6.0-7.4. Cellulose and fiberglass insulation provide the most cost-effective performance. Other less common insulation materials include adobe bricks and straw bales. Straw bales are generally tightly bound with wire or twine, and finished with plaster. Adobe bricks are made of water, straw, and sandy clay. They are shaped into bricks using wooden frames and dried in the sun. Adobe bricks and straw bales are best suited for tropical climates and are also commonly used in passive solar homes or designs.

Benefits of Roof Insulation

As stated earlier, roof insulation helps reduce space heating and cooling. It reduces requirements for heating and cooling system capacities, increases occupant comfort, and even eliminates condensation on roof surfaces in cold climates.

Costs and Installation

Roof insulation should always be installed by a professional. The cost for insulation material is minimal and depending on the size of the project. Labor costs may be minimal as well.