How to fix roof leaks

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Asphalt shingles are the most popular roofing material for homes today, accounting for nearly 70 percent of domestic roofing installations, according to Tom Bollnow, senior director of technical services at the National Roofing Contractors Association (NRCA). And for good reason: Asphalt shingles are lightweight, durable, attractive, and priced well compared to competitive roofing materials.

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While most asphalt shingles are manufactured with the latest advancements in weather- and wind-resistance, fire safety, and long-lasting performance, even the best of them can develop problems over time. The good news is that an asphalt shingle roof is probably the easiest type to repair, since curled shingles can be flattened and re-secured, and old shingles can simply be replaced. Plus, asphalt shingles make the warning signs of a serious roofing problem readily perceptible. Follow the four steps to repairing a leaky roof outlined ahead, and you may find your problem short-lived.

1. Find the roof leak.

If you discover that your roof is leaking—most likely evident by water stains on the ceiling—note the leak’s location, then go outside with a good pair of binoculars to find the roof leak. Look to see if there are any curled, cracked, or missing shingles. Leaks can occur at any point where shingles butt, or where caulking and flashing have been compromised. End caps, the tent-shaped shingles that cover the angular peaks of the roof, can also be the source of leaks, so check those as well.

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2. Secure curled shingles.

Curled-back shingles, for example, can be re-secured by brushing on a coating of asphalt roofing cement or finding its equivalent compound in tubes for use with a caulk gun (like Henry Rubberized Wet Patch, available in a 10.1-ounce cartridge at The Home Depot). When repairing a leaky roof, you’ll want to apply a generous amount of roofing cement to the underside of the shingle to make certain that the edge and corners are secured. Then press firmly to set.

Note: Shingles will be more pliable in warm weather than when it’s cold, so consider that factor when resolving problems.

3. Replace damaged or missing shingles.

If shingles are cracked, missing, or rotten, replacing them may be another simple fix for repairing a leaky roof (provided you have the replacement shingles). To remove a damaged shingle, lift the edges of the surrounding shingles and carefully remove nails with a pry bar. Once the nails are removed, the shingle should slide out. Scrape away any of the residue cement from the roof and level or remove protruding nails.

Before you attempt to replace a new shingle, round the back corners with a utility knife. This will make it easier for you to slide the shingle under the one above and align it with those on either side. Once you have it in position, lift the corners of the overlapping shingles and fasten the top of the new replacement with 6d galvanized roofing nails (like these 2-inch options from The Home Depot). Be sure to secure with nails in each corner. Last, cover the nail heads with roof cement and smooth down the overlapping shingle edges.

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4. Fix flashing.

To repair leaks caused by metal flashing around chimneys and dormers, simply reseal joints using a caulk gun filled with roofing cement. If you see damage to joints previously sealed with a line of roof cement, apply a fresh new coat with a putty knife.

If it’s necessary to replace an entire row of shingles, or if you find that shingles lift off from the roof too easily, it may be time to call in a professional roofer to inspect the situation. Spot repairs will not extend the life of a roof in need of replacement.

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Expert DIY advice on how to find, troubleshoot, and fix a roof leak, including how to keep the water from getting in during a roof leak emergency.

The source of most roof leaks is hard to find because it originates away from where the leak shows up. In order to find the source of a leak, follow a roofer’s advice and “think like water.”

Water typically comes in through worn, broken, or missing shingles; where nails have worked loose; or through corroded or poorly sealed roof flashing around vents, skylights, or chimneys or along the intersections of roof planes.

Once water passes the roofing, it flows along the sheathing, roof rafters, or topside of ceilings until it finds a place to drip down—inevitably onto your favorite piece of furniture.

Look for a roof leak during the day. Go into the attic with a bright flashlight; step only on secure framing members and never on the insulation or topside of the ceiling below—neither of these will support you! Start above the place where the drip has occurred and work your way uproof, looking for wetness along the framing members.

If the weather has been dry for a while, look for water marks, stains, or discolorations on the wood made by moisture. Then switch off the light and try to find a hole where daylight shows through the roof. (With a wood-shingle roof, you’ll see many such places, but while the overlapped shingles let light show through they shed water.) If it’s still raining, put a bucket under the leak in an area with proper support. Let the bucket collect the drips and fix the leak when the weather clears.

HomeTips Pro Tip: For safety’s sake, don’t go onto a roof that is steeply pitched, don’t step on the plastic sheeting (particularly if it’s wet), and never go onto the roof during a thunderstorm.

Water-Testing for Roof Leaks

If you can’t find the cause of a leak from the attic or by visual inspection on the roof surface, wait for dry weather and ask a friend to help you do a water test. To do this, one person goes onto the roof with a garden hose; the other person goes inside the attic with a bucket and a strong light.

The person in the attic watches carefully while the one on the roof floods the roof with the hose, starting at the bottom (the eaves) and slowly working uproof until water from the leak appears in the attic. Once the leak is found, push a nail up through the hole to mark its location for rooftop repair. Mark the surface of the roof with chalk, if necessary.

The exact methods for repairing the roof leak will depend upon the roofing material and the roof’s construction. Based on your roof, please refer to the following articles that offer step-by-step directions:

• Asphalt Shingle Roof Repairs
• Built-up (Flat) Roof Repairs
• Metal Roofing Repairs
• Tile & Masonry Roof Repairs
• How to Repair Wood Shingle Roofing

Roof Leak Emergency

Here is how to make an emergency cover for your leaking roof from plastic sheeting and 2 by 4s:

1 Partially unroll or unfold enough heavy (6-mil) polyethylene sheeting to cover the leaking section of roof, from eaves to peak; add about 4 feet extra, and cut it with a utility knife. Wrap one end around a 2 by 4 that is as long as the plastic’s width; staple the plastic along the 2 by 4. Sandwich the assembly with a second 2 by 4, and nail the boards together with three or four 3-inch or 3 1/4-inch common nails.

2 Place the sandwiched end of the plastic along the eaves. Stretch the sheeting from eaves to ridge, running it over the top of the ridge and down the other side a few feet.

3 Sandwich the top end of the sheeting with another pair of 2 by 4s so the wind will not carry it away. Do not nail any part of this assembly to the roof.

Fast Fix for a Roof Leak

If you know that a roof leak is being caused by a hole, sometimes you can temporarily fix it with a 12-by-12-inch piece of galvanized sheet metal flashing, available at almost any home improvement center or hardware store.

Lift the damaged shingle with one hand, and push the sheet metal flashing up underneath the shingle so the sheet metal covers the hole. It may be necessary to pry up one or more roofing nails in the row above the damaged shingle so you can push the flashing all the way up under the course of shingles above the leak so water will be shed over the metal.

About Do-It-Yourself Roof Repair

Working on top of a roof can be difficult and dangerous. Unless your roof’s pitch is relatively low and you have the necessary experience, tools, and confidence to get the job done safely, you should leave this work to a professional. In this case, please see our affiliate partner, HomeAdvisor, to receive free bids from local asphalt shingle roof repair pros.

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