How To Air Seal Attic Knee Walls

Video done by arlington home energy efficiency team during a weatherization barnraising in march 2010.

How to air seal attic knee walls.

Square hole that s acting like a chimney drafting expensive heated. Installing batt insulation that extends into the attic past the 2 4 studs making sure it doesn t flop over into the attic by adding some kind of bracing and then adding a 2 piece of rigid board insulation on the non attic side of kneewall. Small air leaks into uninsulated attic space are a major source of heat loss in many homes. I watched the gba video.

Adding a rigid foam air barrier to the cold side of the batt is a great way to take care of this issue on a knee wall between finished and. This will help reduce the wind damage on the insulation to keep it in good shape as well as increase its effectiveness. 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. Improving attic knee wall insulation install rigid foam for added energy efficiency.

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. But then for the knee wall it s important to air seal the wall with tyvek or foamboard. Air sealing an attic kneewall the approach used in the video is opposite to what i am thinking of doing. We want to air seal any penetrations or top plates as we do in all attic spaces.

Continue the insulation along the roofline to the roof edge figure 1. Properly sealing and insulating attic knee walls can significantly reduce air leakage and heat loss between the conditioned space and the unfinished attic. How to air seal knee walls along the roofline. The only air leakage in the stud cavities is typically the outlets light switches and access panels.

How to air seal a knee wall in a cape. Here s how to locate the leak spots and plug them without spending a lot of money. Air seal an attic series. Insulate and air seal the ceiling of the attic room.

Fiberglass batts work best if they re enclosed and air sealed on all 6 sides. Chances are your ceiling has the equivalent of a 2 ft. Cover the insulation with a sheet material drywall or rigid foam insulation that is caulked where it meets the plywood floor sheathing which is extended to the outside wall.