Advice on insulating Colorado garage/storage addition (to foam or not to foam)
I’m adding a third garage bay with storage above it to my SW Colorado home (~7,000 hcd days per year, Climate Zone 5). The plan for the roof calls for 4″ of closed-cell foam and 5 1/2″ batts between the rafters (9 1/2″ I-Joists); the plan for the exterior walls calls for 5″ of closed-cell foam (2×6″ walls). Both the walls and ceiling will be covered with 5/8″ sheetrock and painted.
I met with the insulation contractor last week and he suggests using open-cell foam rather than closed-cell foam to avoid the HFC propellant in closed-cell foam. He also likes the idea of a wall that can breathe to the interior.
I have two questions: 1) Is foam a good material for this project and location? If so, which of the foam options is best and why. 2) If foam is not a good option here, what would a better option be?
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