Another alternative for knee walls conditions is to remove and reinstall the batt insulation to qii standards.
How to insulate attic knee walls.
The ceiling and knee wall drywall will act as your air barrier.
Now that the kneewall is.
Knee walls leak heat in at least 2 ways.
Install an air barrier on the exterior of attic knee wall insulation and to block open floor joist cavities under attic knee walls.
Install a top and bottom plate or blocking at the top and bottom of all knee wall cavities.
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.
Lay each unfaced strip of insulation between the.
Assuming styrofoam vent chutes are installed rough cut a foam block to fit between the rafters.
The first point is sealing the soffit venting.
Install insulation without misalignments compressions gaps or voids in all knee wall cavities.
There are two main methods to insulate attic knee walls.
Cut unfaced batt insulation to fit between the floor joists in the space behind the knee wall.
The specific r value for the insulation you need.
In tight attics or odd shaped wall conditions i e.
Through the floor joist.
Attic knee wall insulation.
If you choose to insulate along the horizontal and vertical walls you have four key air sealing points.
How to insulate knee walls 1.
The best materials for the attic and thus the knee wall are spray foam fiberglass and cellulose.
If you plan to insulate the roof deck of your attic then you would use spray foam or fiberglass batts.
This is the obvious part especially if there is no insulation in them.
Then cover that same area with an r 8 fsk affixing it using cap nails.
Any cracks or holes between the insulation material and the knee wall should be carefully caulked.
Use an r value map to determine the amount of insulation you need.
One involves the insulation of the rafter space along the sloping ceiling.
Rake walls it s easier to handle than plywood or thermo ply and still gives you an r 19 r121 assembly depending on the original batt insulation installed.
The top plate of the knee wall should also be properly sealed.
More details online 1.
Keep the attic outside insulating a kneewall and the attic floor behind the kneewall is possible but tricky.