Building Walls In An Attic

Staple insulation between the wall studs and ceiling joists image a.

Building walls in an attic.

Knee walls are short wood framed walls that install between the ceiling joists and rafters in an attic. Framing basics for attic knee walls along the sides of your loft or attic space. At the bottom points of the triangles the rafters meet the top plates of the exterior walls. Use r 30 insulation for the ceiling and r 13 for the walls.

To build your walls to the correct length measure the angle of the rafter by laying a piece of 2x4 inch lumber against the side of the rafter in a vertical position. When insulated and covered with drywall the walls improve the thermal envelope of an attic. Knee walls are not found in all attics and they are not absolutely necessary. Don t mash or compress the insulation into the space.

Step 1 measure the attic. Mark the line that the angle forms along. Consult your local building code and inquire about any necessary permits before beginning any such project. If building a knee wall for storage like karl did with this project make sure to insulate that area as well.

Footnote 12 building envelope assemblies including exterior walls and unvented attic assemblies where used shall comply with the relevant vapor retarder provisions of the 2015 international residential code irc. If your attic space is framed with rafters and is unfinished it has a triangular shape. It needs a certain amount of loft to work properly.