If you do not identify any damage on your roof before it becomes a leak, there are several ways to identify water intrusion. If possible, head up to the attic and check the wood framing for signs of moisture such as dark spots or rot. You can also look at insulation to see if it is matted, damp, or eroding. All can be signs of a roof leak. During and after major rain storms, you can also walk through your home and look at the ceilings and walls for signs of staining, bulging or drips. Should you see any of these, call for professional assistance immediately.