How to Insulate Knee Walls

Knee walls are such attic crawlspaces, half walls built into areas where a wall will not match. Unlike traditional walls with two finished sides, the back of a knee wall is frequently a triangular piece of attic space in which the roof tapers to satisfy the ground. Insulating this distance within the knee wall improves the energy efficiency of the house and prevents heat transfer from the attic.

Utilize an R-value map you need. The for your insulation you need for your home will depend on your area of the nation.

Cut unfaced batt insulation to match between the floor joists in the distance behind the knee .

Lay every unfaced strip of insulation between the floor joists.

Cover the floor joists using another layer of unfaced insulation vertical to the first layer. The next layer should stretch from 1 end of this knee wall area towards the other end.

Use a utility knife to cut strips of faced batt insulation 1 inch longer than the height of the knee wall to create a snug fit in the walls.

Insert every strip of insulation between the studs at the knee wall with the facing led toward the living area of the attic.

Staple the edges of the facing into each of the studs, overlapping the confronting from two pieces of insulation. Use staples every 6 to 8 inches so the insulation holds firmly in place.

Cut strips of unfaced batting.

Stuff each strip. The amount of bags used will depend on the period of the knee wall and the total amount of space below the wall you need to fill.

Insert bags into the area at the base of the knee wall where it meets the gap in the floor joists not covered with rolled insulation.

Caulk to seal around any gaps around power outlet boxes. Add the tube of caulk into the caulk gun and squeeze a bead of caulk to fill the gaps.

Finish the knee wall or wallboard as desired.

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