Attic Knee Wall Sheathing

The death of the 8 sheet one of the biggest items when sheathing a wall vertically is that the sheathing has to be continuous 602 10 4 5 which meant that an 8 sheet wouldn t cut it in many places so longer ones were required.

Attic knee wall sheathing.

Old school roof vents which look like rectangles on the roof work pretty well too. Cover the whole wall. Sheathe the kneewall during framing for new construction. In an ideal world we install soffit vents as intakes make sure the slopes can breathe with ventilation baffles and exhaust through a ridge vent.

It is recommended that insulation be encapsulated on all six sides with a rigid air barrier like sheathing or foam board. Seal all the edges penetrations and seams. Radiant barrier wall sheathing can be attached to the attic exterior side of a knee wall to cut down on radiant heat gain or heat loss in the winter. Sometimes though there are no soffits.

So companies like norbord started creating tallwall windstorm panels to help alleviate this. The best way to handle a knee wall area is to move the thermal barrier to the roofline left and stand up the knee walls after the ceiling has been drywalled. 1 a continuous air barrier can be installed on the exterior of the kneewall framing from the top of the knee wall down to the attic floor including the spaces between the attic floor joists from the bottom of the knee wall to the ceiling deck below or 2 a continuous air barrier can be installed along the underside of the attic roofline from the top of the knee wall to the top plate of the home s exterior wall. Here are the three keys to sheathing an attic kneewall properly.

Seal all the edges penetrations and seams. There are two ways to insulate triangular attics behind kneewalls. There is bare insulation just hanging between the 2x4 s so an air barrier looks to be needed. This helps keep the supply air coming into the room nice and warm.

There are two ways to block off this air flow. On one wall that is partially exposed to the outside but mainly in the attic the original builder used fiberboard. Cover the whole wall. Ventilating knee wall attics is challenging.

The traditional approach is to insulate the kneewall and the attic floor behind the kneewall. For production builders who may have less control in scheduling trade partners the knee wall can serve as the thermal barrier right as long as sheathing is installed on the back side. So after we seal up the insulated air barrier for the bonus room knee wall we install a thick blanket of cellulose insulation around the duct. Sheathe the kneewall during framing.

The airflow in the ducts suffers from friction losses and the air loses heat to the cold attic space as it makes its way to the room.