How to Repair Asphalt Shingles Roof Leaks – DIY Roof Repair Guide

repairing-a-roof-leak-in-the-valley Repairing a leaky roof is not as difficult as properly diagnosing and identifying the correct causes of a roof leak in the first place.

In fact, finding the cause of a roof leak is the most challenging aspect of any roof repair. In this guide, we will show you how to identify and diagnose the cause of a roof leak, and how to address it so that there are no more leaks in the future.

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First and foremost, it is essential to know the age of your roof. Most basic 3-tab asphalt shingle roofs will require a complete replacement after about 12 to 17 years of service life. If you roof has any missing or curling shingles, or lots of cracks in the shingles, then it is a sure tale sign that your roof is near the end of its service lifespan and needs to be replaced outright, rather than repaired.

However, if your roof is only a few years old, then you should definitely call the contractor who installed the roof, but if the contractor will not return your calls, then try to figure out the cause of a leak and repair it yourself.

Diagnosing the Cause of a Roof Leak:

If your asphalt shingle roof develops a leak following a heavy rain storm, or after being exposed to hurricane strength winds, then it is likely that your leak happened due to a missing or damaged shingle. If this the case, then your roof problem can be easily solved by replacing any missing or damaged shingles.

Basic Requirements for the Job:

Obviously, you need to be able to use a hammer to drive 6 to 8 roofing nails in, and you need to have a roofing ladder to get to the missing shingles. Make sure you get someone who is knowledgeable and experienced with using a ladder, which will need to be properly secured for you to work off of it safely.

You will also need a pry bar to remove the nails holding any damaged, or rotten shingles in place, or the nails left after any blown away shingles.

Steps to Replace a Missing Shingle:


  • Remove the nails and pull out any damaged or rotten shingles that require replacement.
  • Round off both upper corners and slide a new matching replacement shingle in place of the old shingle, underneath the shingles of the row above it.
  • Align the new shingle with the shingles to the left and right side, and make sure that its vertical lines match the established pattern for other shingles.
  • Apply and spread a bit of roofing cement (You can get it a home improvement store) with a putty knife underneath the corners of your replacement shingle. Lift up the shingles above it to make room for you to nail in your replacement shingle, securing it at the corners with galvanized roofing nails (these can be picked up at your local home improvement store).
  • Once you have secured the corners of your replacement shingle, put in four roofing nails across the nailing line of your replacement shingle at about 1/2 to 3/4 inches above the edge of an overlapping shingle from the row above.
  • Once your replacement shingle is fully secured in its place, cover the nail heads with the roofing cement, and you are all done!
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Identifying and Repairing Any Breaks and Gaps in a Roof Flashing:

If all of your roof’s shingles seem to be intact, then you will have to investigate further, which will require looking for any breaks or damages to your roof’s flashing including any vent pipes, chimney, and skylight flashing if applicable. You will need to get up onto your roof, and look for any damage or breaks in the flashing, especially around chimney and any other roof penetrations.

If you find any breaks anywhere in the roof flashing, or any gaps in the roof cement, then you know that you will have to either reinstall the flashing, or repair at the point of failure.

Normally, you can use a solar seal exterior grade caulk, or a roofing cement to repair any breaks in the roof flashing.

If you cannot find any problems with your roof’s shingles, and all the roof flashings seem to be intact, then check to see if your roof has a sufficient pitch for an asphalt roof. If your roof’s pitch is less than 3 to 12, then it is likely that your roof is subject to leaks due to a wind driven rainwater.

If your roof has a solid pitch of 5 to 12 and steeper, then be sure to also check the gables/side edges of the roof to see whether the gable flashing is installed underneath the shingles on all gable sides of your roof.

If there is no metal flashing in place, then it means that your roof was installed by a lousy crew, and needs to be redone. The cause of your roof leak, in this case, would be easily explained by the absence of a gable flashing, which makes your roof vulnerable to a heavy rain coming at an angle due to strong winds.

If your roof leaks due to ice dams, or due to a poor roof design such as when a dormer wall is covered with melting snow during winter, then you will need a professional correction to address the flaws in your roof’s structural design.

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  1. This is the first place I chose to look when I realized my roof was leaking. I just want to say that I found this resource very helpful and informative and I plan to follow this very sound advice! Thank you for posting this resource!

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