CommunityInsulation Behind Knee-walls in Finished Attic

Insulation Behind Knee-walls in Finished Attic

My wife and I are buying our first money pit!  It's a 1.5 story stucco single family, and the upstairs attic has been finished into a bedroom.  We noticed behind the knee walls, in the unfinished portion of the attic, there doesn't appear to be any insulation.

How and where do we add insulation?  on the floor or under the roof?  If the floor, how do we maintain the area as storage at the same time?

Thanks in advance!!!

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3 Answers
Guest Staff answered 6 years ago

You need to understand where the line is between the conditioned and unconditioned space.  In a cape with a finished attic, the insulation is usually in the rafters down to the knee wall, and in the knee wall itself.  The floor below the finished 2nd floor is not insulated.

Also, it is important that the rafter insulation leaves room for ventilation.  If the rafters are 8 inches deep, the insulation should be 6 inches, and ridge vents be added to keep the air moving. 

kcitti answered 6 years ago

Thanks for the response Tom!


If I am understanding you correctly, insulation should be surrounding the finished portion of the attic only and within the walls of the finished area? No need for insulation in the unfinished portion on the floor or in the rafters is necessary?

Guest Staff answered 6 years ago

The rafters or ceiling above the finished are should be insulated, but not in the unfinished area.  If there's eat oin the other side of drywall, it should be insulated!