Warning signs include cracked caulk or rust spots on flashing; shingles that are buckling, curling, or blistering; and worn areas around chimneys, pipes, and skylights. If you find piles of colored grit from asphalt roof tiles in the gutters, that’s a bad sign—those sand-like granules cover the surface of roof shingles and shield them from the sun’s damaging ultraviolet rays. Black algae stains are just cosmetic, but masses of moss and lichen could signal roofing that’s decayed underneath.
Any loose, damaged, or missing shingles should be replaced immediately. Check for popped nails that need to be hammered back in place. Metal flashing around chimneys, skylights and attic vents that has separated needs to be resealed with caulk.
Plumbing vent pipes are often flashed with a simple rubber collar that can deteriorate in the hot sun. Check closely for cracks and gaps. Make sure a chimney cap is present and properly installed. “Caught early, these are easy repairs,” says Beahm. “Left alone, they can turn into very costly problems.”
If you’re comfortable working on a roof, then it’s not too difficult to replace shingles and caulk flashing yourself. Cost: $24 for a bundle of shingles, $5.75 for roofing caulk. Allow a half-day to make a few repairs.
Be alert to early signs of a roof leak
Check the condition of your roof at least once a year, and plan in advance for necessary repairs. Early signs of trouble include dark areas on ceilings, peeling paint on the underside of roof overhangs, damp spots alongside fireplaces, and water stains on pipes venting the water heater or furnace.
If you’re inspecting on your own and find worrisome signs, especially if the roof is old or there’s been a storm with heavy wind or hail, get a professional assessment. Some roofing companies do this for free; specialized roof inspectors, like those who work through the National Roof Certification and Inspection Association, charge about $175.
Remove leaves from the roof
If you have a simple peaked roof surrounded by low landscaping, your roof probably stays clear of leaves on its own. But if the roof has many intersecting surfaces and dormers, or if towering trees are nearby, piles of leaves probably collect in roof valleys or near chimneys. If you don’t remove them, they’ll trap moisture and gradually decompose, allowing wind-blown seeds to take root.
If you have a low-slope roof and a one-story house, you may be able to pull the leaves down with a soft car-washing brush on a telescoping pole. Or, you can use a specialty tool like a roof leaf rake, which costs about $20. A leaf blower gets the job done too, especially on dry leaves, but you’ll need to go up on the roof to use it. If leaves are too wet or too deep, you might need to wash them off with a garden hose. Don’t use a pressure washer, which can force water up under the shingles.
Trim overhanging branches
A little prevention in the form of tree-trimming goes a long way toward keeping leaves and moss off your roof, and it can also keep squirrels and other rodents from gnawing into your roof or siding. To keep critters away, remove branches within 10 feet of the roof.
If that’s not possible, wrap a 2-foot-wide sheet-metal band around nearby tree trunks, 6 to 8 feet above the ground, so squirrels can’t climb up. Trimming branches that hang over the roof is a job for a pro, though, or you might cause more damage than you prevent.
Prevent ice dams
If you’re plagued by ice buildup on the roof, removing some or all of the snow between storms might forestall leaks into your house. Don’t try to pry off ice that’s already formed, since that could damage the roof. Use a roof rake to dislodge snow within 3 or 4 feet of the gutters. Get a telescoping pole and work from the ground, if possible.
If you must be on a ladder, work at an angle so the falling snow doesn’t push you over. Inadequate insulation and air leaks into your attic greatly increase the risk of ice dams, so once the storms pass, address those problems, too.
An alternative is to hire a roofing company to remove the ice buildup. Technicians will steam away the ice and remove any remaining snow. Expect to pay around $500 and up for the service.
Clean the gutters
When leaves collect in the gutters, the rainwater-collection system becomes clogged and roof runoff spills over the side. That can damage your siding and cause basement flooding. Worse, the water can back up into the structure of your home, where it leads to rot, infestations of wood-destroying insects, and interior paint damage.
Forget about the various screens and covers marketed to keep leaves out—they don’t work and can actually worsen problems, says according to engineer Victor Popp, a home inspector in Hingham, Mass. Instead, just keep your gutters clean by reaching gloved hands into them and scooping out the muck—or hiring a gutter company to do the job (around $100 to $200). Clean gutters at least once each fall, plus once in the spring, depending on how leafy your property is.
Clear the roof of moss
“Neglecting moss can shorten the life of your roof by several years,” warns Jim Katen, a home inspector with Associated Master Inspectors in Gaston, Ore. “Moss keeps the body of an asphalt shingle soaked so it tends to get more freeze-thaw damage in the winter.” Added to that, it produces organic byproducts that make the shingles more brittle. Nor are shake roofs immune from moss damage. Moss holds moisture against the wood, speeding rot. Moss can even crack cement or ceramic tiles.
Moss eradication should begin in the fall by applying a moss killer intended for roofs (granules for lawn use contain iron which will stain a roof). In the spring, use a broom to remove remaining dead moss. Spread moss killer along the ridge of the roof and on any remaining green patches. Cost: $20 for moss killer to treat 3,000 square feet of roof. Allow about 3 hours to sweep the roof, clear the gutters, and apply the granules.
Replacing the roof
If your asphalt roof is 15 years old or more, it may be due for replacement. The national average cost for a new asphalt shingle roof is $18,488, according to Remodeling magazine’s 2013 Cost vs. Value Report, of which you’ll recoup $11,633 at resale (62.9%). For high-end materials, such as standing-seam metal, the cost jumps to as much as $33,880.