Insulation for Cathedral Ceiling
I want to raise the ceiling to cathedral and is thinking of using rigid EPS board as insulation. But what is the actual R value for such application in zone 4 (northern NJ), since the chart gives different numbers for the wall, attic, etc? The rafters are 2×6. The 2-inch board gives R-10, and perhaps I can use two pieces of them? By the way, when using the EPS board, is ventilation space no longer an issue compared to the traditional insulation?
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