How can wind-driven rain be a problem?
Wind driven rain can cause shingles to lift up and allow large amounts of water into the open areas of the roof. This can soak underlayment, felt, sheathing, and even insulation. Therefore, if you have loose shingles, wind-driven rain can be a big enemy. This is a big reason why it is so important that the roofing material is nailed down properly. We don’t want roofing materials to be doing the fan wave ever.
