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Community and Q&A

Is insulation required for an unvented exterior 12’x25′ portico roof in climate zone 7B?

Ed Cabler | Posted in Energy Efficiency and Durability on

New barn construction is using an unvented roof (metal shingles over underlayment and 5/8″ plywood) with closed cell spay foam in the interior cathedral ceiling.

The exterior portico entrances and shed roof over a deck are also unvented and will have 1×4 T&G cedar covering the rafter bottoms.

Is insulation required in the exterior areas? If yes, what would be recommended?

Thank you, Ed

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  1. GBA Editor
    Martin Holladay | | #1

    1. Is this a barn or a house? Here in Vermont, most barns aren't insulated.

    2. Roofs over exterior areas don't need insulation.

  2. Ed Cabler | | #2

    Hi Martin,

    Thank you for the feedback. It is a 2 story barn (which looks more like a house using stick construction). The 1st story tack room, feed room and lab will be heated.

    The second story floor is 12" engineered wood I joists covered with 1-1/8" T&G plywood. The unheated 2nd story will be used for hay storage. Part of the second story may be heated in the future.

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