If you do need to install insulation in the roof assembly take into account some rules.
Insulating sloped attic ceiling.
Insulating unvented sloped ceilings here are your top insulation choices for unvented sloped ceilings.
It s more effective and easier to install insulation on the attic floor than in the roof assembly.
For attics with sloping walls formed by the roof s angle stapling the facing to the framing ensures it stays in place protecting both your family and your pocketbook.
Works well at flat sections of ceiling but has not settled evenly between rafters at the sloped sections has all fallen to the bottom of sloped ceiling.
Living under the roof in a 1 1 2 storey home with sloped ceilings at top floor.
You would not fill up the entire eight inches deep because you want to leave that extra two inch space between the end of the insulation and the underside of the roof sheathing so that you can flush air through that.
Unless in air conditioned attics insulation is typically installed on the ceiling plane not on the sloped roof assembly.
The horizontal ceiling accounts for around 40 of the total ceiling area and is insulated with glass fibre between the joists accessed via the loft hatch.
Install 4 inches of spray foam on the underside of the roof sheathing and fill the rest of the cavity with fiberglass batts.
Install 7 inches of spray foam on the underside of the roof sheathing and leave the rest of the rafter cavity open.
Insulating a sloped ceiling.
Previous owner blew celluose insulation in attic.