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Insulating roof in front of shed dormer

K_Buss | Posted in GBA Pro Help on

Hi,

I live in Iowa (Z6), and I’m wondering what is best to insulate the roof behind the knee walls/shed dormer (attic) on the front side of our one and half story house.  The knee wall attic on the front side of house goes the whole length of the house and in the middle is the shed dormer which is its own room.  I believe there is no soffit vent just gable end vents in the top attic.  I’m thinking about installing vented soffits.  The rafter is 2×6, and currently the small attic has 1″ foiled on both sides Balsam-wool insulation on the rafter. If I insulate the roof & vent (make the space conditioned) in the attic on both sides of the dormer then how should the roof be insulated in front of the dormer due to the roof going into a wall? 
1. Should I treat the whole attic space behind the knee walls & dormer as unconditioned attic so seal & insulate the walls and floor where needed (due to some of the attic has a porch under it)?  That way the whole space can be vented to the top attic.
2. Treat the roofs on the sides of the shed dormer has conditioned space and create unconditioned non-vented attic space in front of the shed dormer?  So in the attic insulate the dormer wall and attic floor only where the floor is above the inside of house?  
3. Treat the roofs on the sides of the shed dormer has conditioned space and create conditioned non-vented attic space in front of the shed dormer?Insulate between rafters with rigid board & seal and then put a 4″ rigid board on under side of rafters?

I just don’t want to create moisture issues, and a new roof was put on about 5 years ago.

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