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TOPIC: General Discussion

To Sheath or not to Sheath

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I am building a cottage up north and have decided on metal roofing. I'm still in a state of sticker price shock after seeing the estimate for my building materials, and am looking for ways to reduce cost. I've heard that without roof sheathing, moisture on the inside of the metal roof will result in condensation, potentially damaging and rotting out the attic insulation. I've also heard that if you do a good job ventilating the attic, then sheathing is not required, allowing the metal sheets to be fastened to 1x4 strapping. Have you got an opinion on this matter? I'd appreciate it very much. Thanks
Tom Duane

5/12/2005
Some metal roof products can be installed on lathe boards. Other MUST be installed on solid decking. If you choose a product that can be installed on lathe, I suggest contacting its manufacturer to make sure they are agreeable to installations over lathe on jobs similar to your home. In either case (lathe or solid decking), I am a big proponent of good ventilation, with both intake and exhaust, to guard against condensation. As for my personal opinion, I'd prefer to see an installation done over solid deck and underlayment. Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/12/2005
Thanks for the tip. Regarding your comment on good ventilation, are you referring to the appropriate intake via soffit, and appropriate exhaust via roof venting? My plan is to use continuous ridge vent for the exhaust. Are there other ventilation techniques I should be implementing? I appreciate your help. Regards, Tom
Guest User

5/13/2005
Nope -- soffit vents as intake and ridge as exhaust has been proven to be more effective than other passive venting options. I think you're on the right track! Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/13/2005