Insolating The Attic Directly On The Roof Joints

If you re insulating the roof directly to insulate the roof itself you either use spray foam or retrofit with it with rigid foam board.

Insolating the attic directly on the roof joints.

The technically correct approach depends on a number of factors. Whether or not there is an inner roof lining and the total thickness of the roof structure. An advantage of spray foam is it s quick whereas foam board needs to be cut and measured which can be a chore. Essentially this system offers excellent insulation value because wood conducts heat and cold.

Place the plastic sheeting on top of the rolled insulation. An unfinished attic is an attic that is not considered part of the living space. With one inch extruded polystyrene foam board insulation between the drywall and the roof members the r value increases to r 25 with no thermal bridges. If there is a floor you will need to remove it to properly insulate the roof rafters.

When hvac equipment is in the attic insulation and an air barrier at the roof line brings that equipment within the conditioned enclosure envelope thereby allowing it to operate in more favorable temperature and humidity conditions without air leakage and heat loss gain directly to the exterior. Do not use plastic sheeting in this case. They are the easiest to insulate because the insulation is installed between the framing members or joints of the floor according to the university of tennessee extension.