Insolating The Attic Directly On The Roof Joints

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.

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. Insulating the pitched roof if your attic is often used or perhaps you plan to convert it in the future you will need to insulate the inner surfaces of the roof. Place the plastic sheeting on top of the rolled insulation. Insulating an unfinished attic can be a simple diy project.

An advantage of spray foam is it s quick whereas foam board needs to be cut and measured which can be a chore. 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. Essentially this system offers excellent insulation value because wood conducts heat and cold. If the plastic sheeting is in pieces overlap the pieces by 8 inches and staple it in place directly to the roof rafters and the wall.

If there is a floor you will need to remove it to properly insulate the roof rafters. An unfinished attic is an attic that is not considered part of the living space. The technically correct approach depends on a number of factors.