There are as many ways to do it as there are people who do it.
Insulate attic knee walls.
They are short walls usually no more than 3 feet high used to support the rafters in roof construction with attic space behind them.
If you re insulating an attic the knee walls are important.
Insulating knee walls other spaces in the attic.
This method can be made to work but the necessary air sealing details are demanding and fussy.
A better approach is to insulate the roof slope above the attic.
If you plan to insulate the roof deck of your attic then you would use spray foam or fiberglass batts.
Insulating only the attic roof rafters and the walls at the end of the attic is one method some use to insulate the knee wall area underneath but carson dunlop author of principles of home.
One of the best methods is rigid foam board with sealed joints over insulation in the knee wall.
Knee walls are found in many older houses where the ceiling on the top floor is an attic or.
The traditional approach is to insulate the kneewall and the attic floor behind the kneewall.
When it comes to insulating knee walls you will want to insulate this space using the same material and method as the rest of your attic.