Do dormer bungalows and houses with attics in the roof space need a different approach to insulation.
Dormer attic insulation.
1 the first method is to use rigid insulation.
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.
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.
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.
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.
There are a number of options for insulating a new dormer roof.
Dormer roofs are roofs that contain rooms and can present considerable challenges when it.