Coop/run roofing

[Sefirothe]

I'm still in the mad planning stages for my coop/run build and am reading everything I can get my hands on.

I'm planning to roof my run and probably the coop with plain 31 gauge galvanized steel roofing from Home Depot. But what I'm not sure of and have no one to ask, is if I need to support under it with plywood. Or can I attach the metal sheets directly to the rafters?

Where I live, the winters have been progressively getting milder, but we have had snow storms in the recent past that dumped 2-3 feet of snow in one go. Last thing I want to have happen is to get another one of those and have the roof collapse.

 

[DobieLover]

You still get freezing weather in Scranton. One of the risks of using a metal roof in freezing weather is vapor condensing on the metal surface and dripping back down on the birds. The only way to stop that is to put insulation up that blocks the air from contacting the bottom surface of the metal. But if you want to use it that's fine. Just be aware of the risks which are quite high when you have a poorly ventilated coop.
You don't attach directly to the rafters. You have to attach purlins running parallel to your ridge beam and fascia every two feet along the rafters. And then you attach the metal roofing to the purlins screwing through the tops of the corrugations. Not the bottom. You have to use special screws for it as well.

 

[aart]

You still get freezing weather in Scranton at. One of the risks of using a metal roof in freezing weather is vapor condensing on the metal surface and dripping back down on the birds. The only way to stop that is to put insulation up that blocks the air from contacting the bottom surface of the metal. But if you want to use it that's fine. Just be aware of the risks which are quite high when you have a poorly ventilated coop.
You don't attach directly to the rafters. You have to attach purlins running parallel to your ridge beam and fascia every two feet along the rafters. And then you attach the metal roofing to the purlins screwing through the tops of the corrugations. Not the bottom. You have to use special screws for it as well.

What she said^^^
...and make sure your framing underneath it all is sturdy enough to hold the snow load.

 

[Sefirothe]

Hmm, did not think of that. Maybe standard shingle roof on the coop. And metal on the run which should have more than enough ventilation.

That would at least allow for using the couple sheets of reclaimed metal panels I have! There wasnt enough for the coop and run so I was going to buy all new so it would match.

 

[3KillerBs]

Another way to prevent condensation on a metal roof is to have generous ventilation at the top and bottom of the roof slope so that the warm, moist air is carried of by the air current (well above the birds' heads), instead of hitting the underside of the roof.

Whether or not this is adequate depends on the exact nature of your climate -- just what combination of temperatures and humidity you see at the same time. Some areas are so prone to condensation that roof insulation is a necessity. Others will never see it at all even without adequate ventilation.