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Common Roof Problems and How to Fix Them

Staying on top of these common issues will keep the water outside, where it belongs.

Roof shingles with garret house on top of the house among a lot of trees. dark asphalt tiles on the roof background. iStock

That roof over your head, the one that keeps you dry and protects you from the elements? It will weather storms, wind, sleet, and snow for decades, but it won’t last forever. There are a handful of potential issues—old or torn shingles, worn-out flashing, clogged gutters, and more—that will degrade the roof. It’s a gradual process—first a loose shingle or worn piece of flashing lets in a little water, then decay develops, and soon you have water ruining your house. The best thing to do is to fix these small problems before they grow into big, expensive ones. Here’s what you need to know.

Common Roof Problems

Signs you have a roof leak

Roof leakage, water damaged ceiling roof and stain on ceiling close-up iStock

A leak in your roof doesn’t have to present itself as a torrent or even a steady drip, drip, drip. If you suddenly find a wet spot on your ceiling or a stain on it that keeps growing, you may have a small leak. If you have access to your attic, look inside at the area above the leak. Do you see wet insulation or stained areas on the sheathing or rafters? You may even want to have someone soak targeted areas of the roof with a hose while you examine below. Once you’ve found the leak, you’ll have to find the corresponding problem on the surface of the roof.

Note: Many roof surfaces—especially tile, metal, and slate—can be very slippery, and, combined with a steep pitch, make for a hazard. They are best repaired by a professional who specializes in these particular roofing materials. With any roof repairs, always consider calling a professional—they have the equipment and the experience.

Common Roofing Repairs

Loose, torn, or missing shingles

If you need to replace shingles, you’ll need thee items:

  • Ladder
  • Hammer
  • Flat bar
  • New shingles
  • Roofing nails
  • Caulk gun
  • Roofing sealant

Pick a day that’s not too cold or too hot (shingles get brittle or soft, respectively), and start by using the flat bar to break the seal between the shingles. Slide the bar up beneath the first nail and hit the bar with the hammer until the nail pops out. Repeat until the bad shingles are out. Starting with the lowest course, nail the new shingles in place. At the last course, you’ll have to lift up the shingle above to drive in the nails. Squeeze a bead of roof sealant beneath the leading edge of each replaced shingle and the shingles directly above them.

Vent boots

The rubber boot around the plumbing vents can develop cracks or tears. If the aluminum flashing is not leaking, it may be possible to replace just the boot.

To replace the flashing, you’ll need to choose a boot that fits the vent pipe’s diameter. (You may be able to find flashing units with adjustable boots.) Pry up the exposed front edge of the old flashing with a flat bar, remove any nails, and lift the base and boot off the pipe. Apply a generous bead of roof sealant to the underside of the new flashing unit, then slide it over the pipe and under the shingle course just above the pipe. Replace the nails, sealing any exposed heads, or use nails with neoprene washers.

Other Common Roofing Problems

Leaks can also occur around other areas of the roof’s flashing, such as the counter flashing surrounding the chimney, or the step flashing at the base of a dormer or adjacent wall. If the counter flashing around your chimney is leaking, use roof sealant to repair cracks and glue individual pieces back down.

If you find a leak in the step flashing along a dormer, a sidewall, or around a skylight, there are two options. The first is to replace the flashing, which means you have to strip away the shingles and siding in that area, then reverse the process by installing new flashing and siding.

The second option is to repair the damaged flashing with a judicious application of roof sealant. The trick here is to keep the sealant’s surface relatively smooth—big beads or lumps of sealant can actually divert water, preventing it from draining properly. Nails used to secure flashing should not be exposed; if they are exposed, apply sealant to their heads. In some cases, repair is only a stopgap until the flashing can be replaced with the rest of the roof.

Ice dams

Long icicles and snow overhaning the roof and gutter of a building. iStock

If you live where the winters are cold, you may have experienced leaks caused by so-called ice dams. Warm air escaping from the attic through the eaves causes a freeze-and-thaw cycle at the edge of the roof. Ice builds up, hits the warm air, and as it melts, water finds its way under the shingles and into the house. Don’t try to chop the ice away—it just damages the shingles and doesn’t solve the problem. You can install a roof de-icing cable, but a more permanent solution involves blocking air leaks in your attic, increasing your insulation, and possibly having a roofer install a self-adhesive membrane and new shingles along the roof’s perimeter.

Gutters

If not routinely maintained, gutters can cause problems with your roof as well. A clogged downspout will cause the gutter to back up. Vegetation starts to grow in the gutter, promoting water damage of the fascia, which can result in rotting rafter tails. The overflow can also spill out onto the siding or windows and cause even more water-related problems.

The solution is to clean and inspect the gutters at least once a year. Again, you’ll need a ladder, along with a small garden trowel and bucket to scoop out dead leaves and twigs. It also helps to have a hose up there so you can flush away smaller debris with a stream of water.

If your gutters are older, you may find that repairs are in order. Make sure that the gutter’s attachment to the fascia is solid and replace hangers as necessary. Use a caulk gun fitted with a tube of roof sealant to patch leaky seams.

Moss

Moss growing on the roof of a building. iStock

If your house is even partially shaded, portions of the roof that don’t get any sun may grow patches of moss. If you’re a hobbit, you may think that’s a good thing, but for the rest of us, moss is a problem. It gets under shingles, breaking their seal and causing leaks. It promotes decay in all types of roofing materials, notably cedar and asphalt shingles.

There are several ways to rid the roof of moss. If you happen to be getting a new roof, strips of zinc or copper laid in between shingle courses will prevent moss from growing in the first place. If you’re stuck with your old roof, get a ladder, some slip-proof shoes, a hose (not a pressure-washer) and long-handled scrub brush and climb onto the roof. Standing above the mossy areas, direct a strong spray of water down onto the moss and then use the brush in a downward motion only to push the moss off. Repeat as many times as needed, but be careful not to damage the shingles.

There are commercial sprays such as Moss and Algae Cleaner or Safer’s Moss and Algae Killer that kill moss. Or if you’re more inclined, you can mix one part liquid laundry bleach and one part water, spray it on the moss, and then rinse it off with the hose twenty minutes later.