Roofing?

[wildorchid053]

if you let your shingles hang over the edges a bit then the water won't get onto the wood.. it should drip away

 

[Quadzilla32]

Would it be recommended to put down roof felt if you aren't using shingles? Right now my roof is plywood with metal roofing on top. Would it be overkill or needed to put down some roof felt between the two as another barrier for moisture?