Knee Wall Storage Insulation

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

Knee wall storage insulation.

Below are the components from the table that are applicable to sealing and insulating attic knee walls. If you go back and view the illustration above you ll notice there s an enclosed area behind the knee wall. Another alternative for knee walls conditions is to remove and reinstall the batt insulation to qii standards. Blown insulation in the knee wall and top attics.

Step 9 insert dresser photo by. In tight attics or odd shaped wall conditions i e. 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.

Walls the junction of the top plate and top of exterior walls should be sealed. We prefer cellulose but we use fiberglass sometimes too. The sloped roof creates a small space that can hardly be use. 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.

Use a hammer to remove any knee wall studs from the opening. Then cover that same area with an r 8 fsk affixing it using cap nails. Rake walls it s easier to handle than plywood or thermo ply and still gives you an r 19 r121 assembly. Build the supports out of 2x4s making sure they re flush with the sill of the cutout.

Knee walls also provide pockets for additional insulation in the attic. 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. We reduced the air leakage nearly 50 on this house in shaker heights without insulating the walls. Rather than leaving this space empty homeowners can fill it with insulation for additional thermal protection.

Step 8 install supports photo by geoffrey gross. Kneewalls short walls under sloped ceilings are common in story and a half homes and in bonus rooms above garages. Exterior thermal envelope insulation for framed walls should be installed in. Added bonus the floor of this knee wall leaked too so there is a line of foam just above the floor joist.

Screw two support braces to the attic floor right behind the knee wall.