What is the best way to insulate 2×6 walls without exterior insulation?
I currently undergoing some remodeling and I have new construction second floor walls with 2×6 studs 16″ OC. I am in climate zone 5. We are in the proccess of having Hardie board installed and exterior insulation is not an option right now. I am also hesitant to build and second interior wall as discussed in other answers. I know exterior is the best option but that ship has sailed. What can I do to maximize my insulation from the interior with both value and performance. Do I flash and batt to stop air flow? Do I use rigid and batt? Is my best option just rockwool batt? Is there anything I an do to help mitigate the thermal bridging in the 2×6 studs. I get so many mixed answers and contradicting answers I’m not sure where to begin. Or if someone can point me in the right direction of some articles that would be great as well.
I also have a second question about how I should insulate my attic which has HVAC/insulated mechanical room. I was planning on insulating with blown in but others have suggested I use closed which would clearly be costly.
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