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Porch roof - need insulation and/or ventilation?

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Guest User
4/8/2008
I am building a porch roof over an existing patio. I am not planning on enclosing the porch. The rafters are fabricated I-beams. I plan on putting aluminum soffit under the I-beams. On top of the roof I would like to put down a metal roof. I already put down 3/4" OSB and a rain/ice barrier. Do I need insulation and/or ventilation on top of the rain and ice barrier, or can I get away without it? Won't the temperature changes cause a moisture problem on the underside of the metal roof?
Todd Miller
Isaiah Industries, Inc.
4/8/2008
The correct place to insulate in this case, if you wish, would be in the enclosed "attic" cavity but as long as you are venting this area you should be fine.
Guest User
4/8/2008
Thanks for the reply Todd. I plan on having a small area of vented soffit at the low end of the porch roof. The side at the house can't really be vented (It is lagged into the house at the ledger board). I take from your response that I can just lay down the OSB, ice & rain barrier, then the metal roof. Should I leave the ends of the seams open for some air to get between the ice & rain barrier and the metal roof? ...or won't I have any troubles with moisture between the steel and the barrier?
Todd Miller
Isaiah Industries, Inc.
4/27/2008
My concern would be more with moisture in the attic. Why don't you see if your metal roofing manufacturer can help you come up with a topwall vent?
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