Roof Nosing installation

I always have a question on roof nosing. The metal edge used in roofing. Now I know on the downward slope of the roof that the tar paper goes over the metal roof edge. And the shingles go on the paper. Now on the sides, and up the rake along the facia, does the metal go over the paper or under the paper or does it really matter. I have always been under the impression that metal needs to be isolated from wood too by tar paper or some other form of separation. Since metal gets cold and sweats, it keeps the wood from getting continuously wet. So does that mean the metal edging on a roof needs to be isolated by paper first, and then covered over by the first layer of tar paper. I guess I have over thought this whole process, and worry too much.
I am re-roofing my shop and garage and trying to make sense out of what steps to follow when I re-roof.
john
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I just found info. on a web search. (dah) Metal edging goes under tar paper underlayment on lower edge of roof but along rake it is recommended on top of underlayment although under and over is acceptable. The reason it is better over is to protect wind driven rain from getting under the paper. They still do not address the idea that isolating the edging from the wood is a good idea. Now whenever I install metal windows we always separate the window from the wood frame by paper or a barrier.. too much thought on this subject. john
"jloomis" wrote in message
I always have a question on roof nosing. The metal edge used in roofing. Now I know on the downward slope of the roof that the tar paper goes over the metal roof edge. And the shingles go on the paper. Now on the sides, and up the rake along the facia, does the metal go over the paper or under the paper or does it really matter. I have always been under the impression that metal needs to be isolated from wood too by tar paper or some other form of separation. Since metal gets cold and sweats, it keeps the wood from getting continuously wet. So does that mean the metal edging on a roof needs to be isolated by paper first, and then covered over by the first layer of tar paper. I guess I have over thought this whole process, and worry too much.
I am re-roofing my shop and garage and trying to make sense out of what steps to follow when I re-roof.
john
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There's so little mass of metal that it's essentially the same temperature as the roofing. There has to be a temperature differential between the two materials for differential condensation.
R
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Makes sense. That is why we do the windows. The heat interior, and the cold exterior. I am not isolating the metal on the roof. Just wondering. John
"RicodJour" wrote in message wrote:

There's so little mass of metal that it's essentially the same temperature as the roofing. There has to be a temperature differential between the two materials for differential condensation.
R
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