Rigid insulation the rigid insulation method requires the utilisation of 150mm thick insulation in between the rafters along with a 50mm air gap in order to avert cold bridging.
Insulating dormer attic space.
Measure the dormer s ceilings for insulation with the tape measure if needed.
If the air distribution is in the attic space then consider insulating the rafters to move the distribution into the conditioned space.
Cut the ceiling s batt insulation to size with the knife.
1a attic access door.
If only the living space will be insulated wrap the insulation around the room s walls and ceiling and then continue along the floor of the non living space.
Staple the dormer s ceiling insulation s flaps to the roof trusses with the insulation s paper backing facing down.
If the attic kneewall spaces are used for storage then you ll have to insulate along the roof slope down to the eaves and create an air barrier at the rafters.
2d extend insulation into joist space to reduce air flows.
Do not insulate the dormer s ceiling when it connects to an uninsulated attic space.
In finished attic rooms with or without dormer insulate 2a between the studs of knee walls 2b between the studs and rafters of exterior walls and roof 2c and ceilings with cold spaces above.
Do dormer bungalows and houses with attics in the roof space need a different approach to insulation.
In this case the area behind the knee wall will be uncomfortably hot or cold.
There are two basic ways to insulate a finished attic.