Knee Wall Storage Insulation

Anytime i conduct an energy audit of a cape cod or 3 story colonial or a salt box i know that a good chunk of the homeowner conversation and audit report will deal with the knee walls.

Knee wall storage insulation.

Then cover that same area with an r 8 fsk affixing it using cap nails. In tight attics or odd shaped wall conditions i e. Knee walls are among the biggest air leakage and heat loss sources in home in part because they are such a pain in the rear to insulate and air seal properly. Build the supports out of 2x4s making sure they re flush with the sill of the cutout.

If you go back and view the illustration above you ll notice there s an enclosed area behind the knee wall. Blown insulation in the knee wall and top attics. Also be sure to remove any insulation. Although kneewalls can help turn attics into living space they often present insulation challenges most builders install fiberglass batts between the studs and some type of blown insulation between the floor joists.

Kneewalls short walls under sloped ceilings are common in story and a half homes and in bonus rooms above garages. We reduced the air leakage nearly 50 on this house in shaker heights without insulating the walls. If the attic is not insulated insulate the attic rafter. Screw two support braces to the attic floor right behind the knee wall.

Knee walls also provide pockets for additional insulation in the attic. Below are the components from the table that are applicable to sealing and insulating attic knee walls. Step 8 install supports photo by geoffrey gross. Step 9 insert dresser photo by.

We prefer cellulose but we use fiberglass sometimes too. Another alternative for knee walls conditions is to remove and reinstall the batt insulation to qii standards. Rather than leaving this space empty homeowners can fill it with insulation for additional thermal protection. Rake walls it s easier to handle than plywood or thermo ply and still gives you an r 19 r121 assembly.

Walls the junction of the top plate and top of exterior walls should be sealed. The sloped roof creates a small space that can hardly be use. The knee wall storage unit must be insulated similarly to the attic space or the room will suffer from infiltrating air leaks. While they can be an ideal storage spot knee walls can t do much without being properly insulated fiberglass is layered down on the floor of the knee wall but since fiberglass doesn t stop airflow it doesn t do anything to insulate the area.

R402 4 1 1 n1102 4 1 1 air barrier and insulation installation table.