Retrofit insulation of Mansard Roof
I have a 2 story house with mansard roof in Boston that currently has no insulation. The first 2 floors are going to get dense pack cellulose, but I’m wondering what are my options for the 3rd floor mansard roof. After reading tons of info here and at BSC site, I understand that my best best is vapor impermeable spray foam on the underside of the whole roof.
Of course I would like to avoid tearing down walls and the cost of spray foam.
Is something like dense pack cellulose in the vertical walls and roxul batts(while paying attention to air sealing penetrations) in the little attic of the mansard roof an option?
Are there any other options?
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