jimmy

in a attic open is the way to go i insulate with closed for a living and you need atleast an r 40 in your attic it use to be a r 38 but the closed cell is more for walls

foam or batt only ive done insulation for 20 years and depending on the foam it can cause condensation

retro fit is what you need foam in insulation i do the job your talking about every day we drill a 2 inch hole outside under siding and fill it with foam we also do brick

11 inchs of celloulose is an r 38 it might look profesional but it isnt