I am building an enclosed porch using native lumber. The underside
of the roof will be visible from inside so instead of using 2x6
and plywood, I am using using rough sawn 3x6 rafters spaced at
30", and 1x12 pine smooth on one side for the roof decking.
My question is will the 1x12 ( 7/8 x 11 3/4) be sufficient
at 30" spacing? The roof will be covered with asphalt shingle.
Thanks,

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Jeff