Dormer Attic Insulation

The depth of your rafter will determine what size of insulation should be used and in turn what size of plasterboard slab should be fitted to achieve current building regulations.

Dormer attic insulation.

Fiberglass batts are the worst possible insulation to use in rafter bays because of all insulation types fiberglass is the most permeable to air. Dormer roofs are roofs that contain rooms and can present considerable challenges when it. Knee walls are found in many older houses where the ceiling on the top floor is an attic or there is a dormer window. This method requires the use of 150mm thick insulation between the rafters and a 50mm air gap to prevent cold bridging occurring.

According to the oak ridge national labratory the open joist ends below the knee wall should be sealed with rigid foam high density cellulose or batt insulation. In an existing dormer or 1 5 storey home icynene spray foam insulation can be easily fitted to the difficult to insulate areas such as crawl spaces and closed sloping attic sections using our unique cannon tip application method and in areas totally inaccessible icynene can be injected through the plasterboard. 1 the first method is to use rigid insulation. If interior air gets into the rafter bays the fiberglass batts do nothing to prevent the warm moist air from contacting the cold roof sheathing.