The shingles at the peak of a roof are called cap shingles. (Tim Carter)

Dear Tim: I was inspecting my asphalt shingle roof the other day. At the top of the roof where the peak is, I noticed some defects. My shingles are only six years old so I was shocked to see deterioration. The shingles covering the peak of the roof do not look like all the other shingles on my roof. The color is the same, but they have a strange shape. How can I replace the defective ones without damaging adjacent shingles? What is causing the shingles to go bad so fast? — Sheila P., Waynesville, Ohio

Sheila: Congratulations on doing that roof inspection by yourself. Not many have the nerve to get up and walk on roofs. Just last week I was up on my friend’s steep roof helping to remove a tree that had fallen on his home. The only mistake I made was wearing nice work boots that have a fairly stiff sole. My sneakers that have a more flexible sole would have given me much better traction on the asphalt shingles.

Seven months ago I published a small book that speaks to what you discovered. It’s called “Roofing Ripoff.” I was inspired to produce the book after my own 30-year-warranty asphalt shingle roof began to fall apart in just 10 years!

I did extensive research into why asphalt shingles are failing so fast. In my opinion, the evidence points to too much air being blown into the liquid asphalt as the shingles are being made. This extra oxygen pre-ages the shingles. I cover this in great detail in my short book.

The shingles at the peak of your roof are commonly called cap shingles. If your shingles are standard three-tab shingles, the caps are made by cutting one shingle into three separate parts. It’s very simple to do, and if you’re lucky enough to have some spare shingles left over in your garage or shed, you can make replacement caps in just minutes.

Dimensional or architectural shingles have special cap shingles. You buy bundles of the cap shingles at the same time you buy the regular shingles. Both types of cap shingles are applied the same way.

The overall size of most cap shingles is 12 inches by 12 inches. The shingles overlap one another at the ridge like feathers on a bird. This overlap creates a watertight covering.

The cap shingles often are installed on top of a continuous ridge vent. The vent manufacturers make their products to match the size of the cap shingles so the caps cover the vent material, leaving a 3/4-inch shadow line up at the ridge.

A standard pry bar is required to replace a cap shingle. You also need some warmer weather. If it’s cold outside, there’s a good chance you’ll crack good cap shingles as you try to install new ones.

You need to gently pry up the overlapping cap shingle next to the cap you want to replace. Back about 1 inch you’ll see a roofing nail. Slide the pry bar under the nail head and gently pry the nail from the wood roof deck.

Often you need to go to the second overlapping shingle and pull up those nails, too, as they may be passing through the top edge of the cap you’re trying to replace.

Roofers frequently use nails that are too short when installing cap shingles. You’ll discover in a hurry there’s lots of roofing material up at the ridge. You’ll need nails that are at least 2 inches long to secure the caps. It’s not uncommon to use 2 1/2-inch nails!

If it’s cold and you must do the work, try to work in the sun, as even on a cold day the shingles can soak up enough heat from the sun to make them pliable. Don’t be surprised if you crack failing brittle shingles working in temperatures below 45 degrees F.

Your best bet may be to patch any bad cap shingles with roofing cement for now. Who cares what it looks like for a few months? If you have gutters, you’ll probably discover tens of thousands of colored granules from your shingles in the gutters. Collect some, wash and dry them.

Dab on the gooey roofing cement over the bad areas and immediately cover the sticky cement with the granules to disguise the black blobs. This will work until the air temperature is about 75 degrees F and you can get up and do the job properly.

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