Insulating attic to be finished
I have an unfinished attic that I’m working to finish and condition.
-True 6in roof rafters
-Soffit vents and ridge vent
-Roof will need to be replaced within 5 years
-Zone 5A (Ohio)
-Head-room is limiting the rafter depth I have to work with
I plan on installing 2in Sika Rmax Pro (R13 and foil faced) between the rafters and leaving a 1in air gap between the bottom of the roof decking and the foam board. I plan on having the reflective side face outward towards the roof decking.
I then plan on having 3in of closed-cell spray foam installed to bring it flush with the edge of the rafters.
-Should the reflective side face the roof decking?
-Is it okay to have the reflective side acting as a vapor barrier and then have closed-cell spray foam underneath it which also acts as a vapor barrier?
-All closed-cell contractors I’ve spoken to (5 well known within our area) will not spray more than 3in even though that only gives ~R21. They state that this is fine since it’s much more efficient. Adding the 2″in R13 foam-board will get me up to ~R33. Do people commonly run in to this problem with spray foam companies? How do these companies get around not meeting code?
-It seems mortgage companies in the UK are raising concerns and even refusing houses that have had spray foam installed due to rotting rafters and other issues. Is this not a concern in the US or is it starting to become one?
-I have also seen concerns about romex wiring becoming degraded by spray foam. My wiring is already in place and was assuming that the spray foam would just go over it. Do I need to avoid having the wiring encased by the foam?
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