Spray foam and batt insulation combination
We are renovating our 2nd floor bedrooms due to moisture problems and are seeking the most efficient and cost effective means to insulate. We live in the lower thumb area of Michigan and the the rooms have 2×6 cathedral ceilings. The previous method used was 6″ R-19 kraft faced batts with durovent baffles(improperly installed/long story), with soffet and ridge vents. I do not wish to add to the 2×6’s and shrink the rooms so I need to maximize the use of the 2×6’s. I would like to use 2-3″ of closed-cell spf and fill the rest with either 3.5″ r-15 batts or 2.5″ rigid foam board. I know I will only max out at approximately r-31 but I’ve made my peace with that. I was told not to use kraft faced batts with the foam. Would 2″ of spf against the sheathing plus the 3.5″ batt do the job or would I be better served to put the 2.5″ rigid foam against the sheathing and fill the rest with spf? Or would another method work better. The long story above drained our savings so we are on a tight budget but we don’t want to have to deal with this issue again so we want it done right. Additionally, I read that applying spf in cold weather could be prolematic for the spf. Any truth to this? The insulated area will not be accessible once the work is complete so I won’t know until it’s too late. Trying to sidestep that landmine this time around. Thank you for your thoughts and input.
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