When it comes to your building or structure, there is usually a checklist of requirements needed for the roofing. One in particular that comes to mind? The roof’s insulation, which is an important feature year-round.
When it comes to the roofing assembly, it is important to have a high thermal value, which is a calculation of the roof’s ability to resist thermal loss. In other words, it measures how much the roof allows heat to pass through, thus keeping the hot air hot and the cold air cold. Insulation plays an important role when it comes to thermal value—the better the insulation, the higher the thermal value.
Local codes and the International Green Construction Code, instituted by the International Code Council, specify the required thermal values to reduce the loss of heat in the winter and to provide cooling from heat in the summer. Insulation is a perfect counterpart to any building’s HVAC system, for it aids in both the summer and winter months.
Insulation can be provided by a number of materials in a roofing assembly. The most widely-used insulation within the roofing system is polyisocyanurate, which is installed within the roofing assembly. Others include expanded polystyrene, which also is installed under the roofing membrane, and extruded polystyrene, which can be installed on top of the roofing membrane since it is able to withstand exposure to the weather. Insulation can be added in layers of various thicknesses, depending on the roofing structure. Along with most insulation materials is the use of cover boards, utilized to provide additional rigidity to the roof system.
A roof’s insulation is a necessary component of the overall building envelope. Keeping the building’s hot air hot and cold air cold is its job—and it certainly helps keep bills down and its thermal value up.