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Finishing Attic Space - Best Insulation Plan?

1750 Views 4 Replies 2 Participants Last post by  JMinMaryland

I'm planning to convert my unfinished attic space into an entertainment room. It has a cathedral ceiling, knee walls and flat ceiling. Spray foam would be too costly so I'm looking at fiberglass.

The current plan is:

Cathedral (2x10) - Vent baffles with R38 faced fiberglass batts
Flat Ceiling (2x8) - R-49 faced fiberglass batts
Exterior Walls (2x4) - R15 faced fiberglass batts
Kneewalls (2x4) - Roxul Safe n Sound (to keep noises from entering bedrooms below)

The attached plan shows it better.

I'm wondering if and where this plan could be improved. Maybe with rigid foam board or building exterior walls to 2x6 depth, preventing thermal bridging, etc.

I want this space to be comfortable. Thank you!


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Thanks for the quick response.

Good point on creating the rigid foam vents. So don't use foil faced rigid foam? If I use fiberglass batt Insulation it should still have face right?

My thought on the area behind the kneewall was to keep it like my garage. Insulated but not conditioned. So ductwork would be subjected to less extreme temps, but less work for my hvac.

Are you saying to not insulate the kneewalls and keep it all conditioned?

Thanks for the help!
Thanks for the help!
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