Q: How do you know when an asphalt shingle roof needs replacement? Are there clues to look for before telltale water stains appear on our plaster ceilings?
—Pat, Plymouth, Minn.
A: Tom Silva replies: There are several clues, and the biggest one is age. If your roof is more than 20 years old, there's a good chance it's due for replacement. But younger roofs can fail too, so it's a good idea to inspect a roof at least once a year. Don't use a ladder, though. Binoculars are easier and a lot safer, and you can spot most problems from the ground.
Here's what to look for: numerous shingles that are lifting up, cracked or missing, with curled edges, or with smooth dark areas, which indicate that the protective granules have worn off. Also, go into the attic on a sunny day and, with the lights off, check the underside of the chimney and the stack vent. If you see little pinhole spots of light, the flashing is shot—another indication that the roofing might not be in good shape.
While you're in the attic, scan the underside of the roof sheathing for any new signs of water staining since the last inspection, as well as any soft or moist spots, which tend to show up after a heavy rain. If these problems are widespread, it's a sure sign that you need to call a roofer.