Knee Wall Attic Sealing

From inside the attic check for any openings holes or fenestrations into the knee wall surrounding area.

Knee wall attic sealing.

I can t use fluffy sprayed insulation on the floor because the ceiling below may be removed replaced one day. Properly sealing and insulating attic knee walls can significantly reduce air leakage and heat loss between the conditioned space and the unfinished attic. Once you have the materials you can begin to seal and insulate the knee wall access door through these steps. There are two ways to block off this air flow.

A better approach is to insulate the roof slope above the attic. It looks like they neglected to do the knee walls properly on the great room which has a tray ceiling which is 3 feet high see photo. Use spray foam to air seal these openings if they exist. The traditional approach is to insulate the kneewall and the attic floor behind the kneewall.

This method can be made to work but the necessary air sealing details are demanding and fussy. The best way to provide that sheathing is to use a rigid material. Hi i have a single family home in climate zone 5b the attic is ventilated. I had the attic air sealed and insulated to r50 with blown in cellulose 1 year ago.

Assuming styrofoam vent chutes are installed rough cut a foam block to fit between the rafters. The ceiling and knee wall drywall will act as your air barrier. There are two ways to insulate triangular attics behind kneewalls. Seal each of the six sides of each knee wall.

It also means sealing off all penetrations to the knee wall from drywall penetrations. The first point is sealing the soffit venting. And it might mean building a back to the wall. They just wrapped the knee walls with batt insulation and otherwise didn t do anything else.

If you choose to insulate along the horizontal and vertical walls you have four key air sealing points. Insulate vertical wall on shed dormer with roxul batt and rigid board. Outer attic floor behind kneewall. Apply weather stripping to the door to create a seal.

Georgia recognized this problem about a decade ago and started requiring all attic kneewalls to have sheathing on the attic side and to be insulated to at least r 18. I think i ll cut a piece of plywood a bit larger than the hole like you said and angle it into the kneewall then weatherstrip the inside wall and pull the plywood with foam on back tight against the it and secure with eyehooks to get a tight seal. It is important to choose an air barrier and insulation material that will reduce the air leakage and heat loss as much as possible.