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Replacing Shingles on a Composite Roof

by Lorenz Prem
published on August 31 2011 4:00 pm

Composite roof shingles are the most common roofing material in the United States. They are economical, easy to install, and easy to repair. During the life of your roof you will most likely have to replace one or two damaged shingles. Especially closer to the end of their life shingles are prone to tearing. What a lot of people don't know is how easy it is to replace individual shingles. Instead of spending time and money on hiring a roofer, you can do the work yourself. Let's take a look at what's involved.

Getting the materials

Individual shingles can be bought at the local home center. New shingles will inevitably be of a different color than the ones on your roof. After being exposed to the elements for many years, the shingles on your roof will have a unique color that is impossible to match. The best you can do is match the style and base color of your shingles and let the elements blend the repair into the rest of the roof. Patches are more common on older roofs. It might just be easier to live with a visible patch for a few years until it is time to replace the whole roof.

Working on your roof

The most difficult and dangerous part of this task is to work safely on your roof. You are responsible for your own safety. Make sure you understand how to work with ladders and how to gain access to your roof. No post can tell you how to do that on the roof of your own home.

If you feel comfortable working on your roof without putting yourself in danger, replacing shingles will be the easy part.

Removing shingles

In addition to being nailed in place, shingles stick to each other and the roof sheeting. The underside of each shingle holds two strips of tar that create watertight seals when the shingles are installed on the roof. Break these seal by carefully prying the ends of the shingle upward with your pry bar. Eventually the shingle will resist being pulled up. You have just found a roofing nail. These nails will have to be removed.

In addition to the tar strips, shingles create a watertight seal by using a system of overlapping rows. Each row overlaps the one below it sealing water away from the nails used to attach the lower row. In order to remove the nails holding a particular row in place you have to pry up the row above it and remove the nails you find.

Start removing nails with your pry bar around the shingles you want to remove. Don't worry about removing too many, or the wrong ones. Each nail can be reinstalled in the same hole it came from. Take a mental note of the nailing pattern on your roof. You'll have to replicate it when you nail down the new shingles. There are standard patterns to follow, but the one used on your roof is the one that has worked so far.

Eventually individual shingles will come lose. Remove them from the roof, and place the replacement shingles into place. You may have to cut the replacement shingles to size. Score the underside of the shingles with a utility knife and snap the waste off. The replacement shingles must match the ones they are replacing in size.

Installing the new shingles

With the new shingles in place, it is time to nail them down. Recreate the nailing pattern you found on the existing roof. Start from the bottom working up. If the shingles are lined up correctly, the edges of each shingle will line up with the center of the shingle in the next lower row.

Eventually you'll reach the last row. This row can only be nailed in place while prying shingles in the row above it out of the way. Do this carefully. As you may have noticed during removal, old shingles become very brittle. If you bend them too much, they will snap.

The last nail you pound in finishes the job. The shingles will settle in place given enough time. On the next warm day the tar seal will melt slightly. The new shingles will stick to the existing ones. Unless you are expecting wind-driven rain the next day, letting the shingles settle on their own time is save to do.

Shingles along ridges

The shingles along ridges are installed differently. Ridge caps are either cut from normal shingles, or they are a special kinds of shingles. The process for replacing these shingles follows the same steps as replacing general roof shingles.

  • Pry the damages shingle up so you can reach the nails
  • Remove the nails and memorize the nailing pattern
  • Replace the shingle.
  • Nail the new shingle into place
  • Replace all nails you have removed from other shingles

In some cases ridges require tar seals for the roof to be water tight. You will notice this as you are removing the exiting shingles. If you encounter shingles sticking together, you'll have to apply roofing tar to the new shingles as well. As long as you are applying the tar in the saw manner as it was applied on the existing roof, your patch will be watertight.


Replacing roof shingles is within the reach of every homeowner who feels comfortable working on his or her roof. Creating a waterproof repair is just a matter of installing the new shingles in the same manner as the existing ones were installed. You can learn how your roof was built as you are removing the old shingles. Then recreate that work when installing the new shingles. With just a pry bar and a hammer you can create watertight, long-lasting patches in your composite roof.

About the Author
"Lorenz is the founder of Hingmy. When he is not reviewing power tools or improving the site, he is building things in his workshop or playing hockey."