Insulating A Finished Attic With Knee Walls

Although kneewalls can help turn attics into living space they often present insulation challenges most builders install fiberglass batts between the studs and some type of blown insulation between the floor joists.

Insulating a finished attic with knee walls.

We reduced the air leakage nearly 50 on this house in shaker heights without insulating the walls. A job we finished last week dropped from 4060 to 2150 cfm50 just with knee wall air sealing we were able to get 8 of one wall that had no top plate. In these designs take out attic floor insulation only below the finished space from knee wall to knee wall and insulate the knee walls themselves. In this case the area behind the knee wall will be uncomfortably hot or cold.

Kneewalls short walls under sloped ceilings are common in story and a half homes and in bonus rooms above garages. Despite all the bad publicity reflective insulation is getting lately i like to use it quite a bit on knee walls. Knee walls are half walls built into areas where a full sized wall will not fit such as finished attic crawlspaces. How to insulate knee walls.

If only the living space will be insulated wrap the insulation around the room s walls and ceiling and then continue along the floor of the non living space. Insulating the floor and kneewall requires more careful air sealing but is sometimes easier to insulate since you can use blown insulation. Insulate across the top of flat attic. There are two basic ways to insulate a finished attic.

1a attic access door. Blown insulation in the knee wall and top attics. We prefer cellulose but we use fiberglass sometimes too. Unlike traditional walls with two finished sides.

If you want the attic to be outside then using foamboard on the attic side of the knee wall is a good idea. In finished attic rooms with or without dormer insulate 2a between the studs of knee walls 2b between the studs and rafters of exterior walls and roof 2c and ceilings with cold spaces above.