Why Do Asphalt Roof Shingles Curl?

I know you are going to have a hard time with this one, but would you believe that your roof, that bastion of protection from the elements (okay, maybe not so well against Midwest tornados and softball sized hail in Guilderland) actually has to breathe? Yes, it needs air and sometimes this can be a real problem. . . . → Read More: Why Do Asphalt Roof Shingles Curl?