Insulating a finished attic there are two basic ways to insulate a finished attic.
Insulate attic roof or floor.
In this case the area behind the knee wall will be uncomfortably hot or cold.
Whenever possible do insulate the attic floor underneath the subfloor and final flooring materials.
Unless in air conditioned attics insulation is typically installed on the ceiling plane not on the sloped roof assembly.
This is the best way to conserve energy in the main part of the home especially if the attic is on its own zoned heating system or if it s used infrequently and its cooler warmer temperatures negatively impact the rooms below.
Plan to pull up the flooring and layer new insulation on top of the old.
Then you could simply insulate the pitched roof.
It s more effective and easier to install insulation on the attic floor than in the roof assembly.
Materials commonly used for the insulation of the roof deck include.
If you do need to install insulation in the roof assembly take into account some rules.
You may also insulate your roof to help regulate the temperature in an attic that is a part of your living space.
But if the floor is covered in plywood you can t stuff enough insulation beneath it to do the job sufficiently not even in warm climates.
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.
But the best solution is actually to insulate both the attic floor and the underside of the roof.
Insulating the roof is a priority if the ceilings of your home happen to be part of the roof deck as is the case with cathedral ceilings.
At the same time the areas below the roof benefit from increased comfort both during the winter and the summer.