Hot Roof Insulation If you're wondering whether you should get a hot roof insulation, read on. Hot roof insulation works by adjusting the temperature of the attic to within 10 degrees of the indoor temperature of your home. The warm air that would otherwise escape your home is then drawn up into the attic. There are two types of hot roof insulation: open-cell foam and closed-cell spray foam. Closed-cell foam is easier to apply and provides a more airtight seal. However, closed-cell foam does not block sound transmission and is more expensive. To decide which one to choose, you must measure the depth of the existing insulation and estimate its R-value. If your insulation has become damaged, discard it properly. There are several advantages to hot roof insulation, and you should definitely try it out. Besides preventing hot air from escaping from the attic, closed-cell foam can be installed directly under the surface of the roof. When used correctly, closed-cell spray foam makes the attic a part of the conditioned house space, essentially eliminating the need for roof venting. It should be installed by a certified spray foam contractor. In addition to this, you should get approval from your local building inspector, so make sure you choose a certified contractor.