Best bang for the buck: insulation choices in a story-and-a-half home in Zone 5
Hi there, I’ve got a 2500 sq. ft. home that I need to make some decisions on in the near future. I currently have the home gutted down the studs. The exterior walls are 2×6 and the ceiling joists in the roof are 2×6 as well. The house was insulated with open faced batts with a foil backed drywall used as a vapor barrier (I assume). The 2×6 attic joists in the second story were insulated with a combination of faced and unfaced batts. The kneewall was insulated and a plastic barrier was attached to the back side of the kneewall. I’ve since ripped all of that out. I’m looking at potentially insulating with spray foam (not sure whether or not to go with open or closed cell) in a ventless roof manner. I need to know the right way to go to not only do it right, but also to get the best bang for the buck. I can fir down the ceiling a little bit, but I’m going to be very hard pressed to get r-60 in the roof of this home based on the house design. Please help :).
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James,
Q. "I'm looking at potentially insulating with spray foam (not sure whether or not to go with open or closed cell) in a ventless roof manner. I need to know the right way to go -- to not only do it right, but also to get the best bang for the buck."
A. If you have already decided to use spray foam, then I advise you to choose closed-cell spray foam rather than open-cell spray foam. If you want to read more on this issue, see Open-Cell Spray Foam and Damp Roof Sheathing.
If you are open to considering other insulation options, you are likely to discover that other types of insulation are less expensive than spray foam. To learn how to insulate your cathedral ceiling with cellulose or other types of insulation, see How to Build an Insulated Cathedral Ceiling.