How Often Should You Replace Your Roof Shingles?



Any damage or signs of wear call for immediate action to keep water from seeping under the shingles and rotting the wood sheathing beneath. Ignoring a problem—even what appears to be a small one—will accelerate the need to reroof and can add hundreds of dollars to the cost of a new roof.

If your roof is more than 20 years old and most of the shingles are damaged or badly worn, it’s time to replace it. But if your roof is basically sound and is at a relatively shallow pitch that you’re comfortable working on, you can probably handle most repairs yourself.

Here, we’ll take you through the three most-common ones: replacing asphalt shingles; gluing down a badly curled shingle; and repairing shingles that have cracked.

1. Replacing Roof Shingles

If part of a shingle is missing, you’ll have to replace the whole thing. First see if you have any leftover shingles from the last time the roof was worked on (with any luck, the builder or the roofer who handled the job left some behind). If not, you’ll have to buy a bundle at a home centre or lumberyard ($15 to $20 per square—100 sq. ft.—of standard three-tab shingles). If you can’t find a perfect match, choose the closest one.

Replacing a damaged shingle requires a hammer, a flat pry bar, a utility knife and a handful of 11/4-in. roofing nails. Each shingle is initially secured with four nails; when the next shingle course above is installed, however, its nails also pass through the top edge of the shingles in the course below.

Begin removing the first row of nails by sliding the pry bar under the shingle immediately above the damaged one and gently lifting it to free it from the sealer strip. You’ll see the first row of nails beneath.

Slip the pry bar under the damaged shingle and pry upward. Once the nail pops up about 1/4 in., remove the pry bar, press the shingle down and pull out the nail. Repeat this procedure for the remaining three nails. Then push the pry bar under the shingle directly above the damaged one and remove the second row of nails the same way. After yanking all eight nails, pull out the damaged shingle.

2. Fix Curled Roof Shingle Corners with Caulking

As asphalt shingles get older, their corners often begin to curl downward or upward. If you notice a shingle starting to curl, you can forestall the inevitable curling by gluing down the curled section.

Use a caulking gun to apply a dab of roofing sealant (about $4 per 10-oz. tube) under the corner. Weigh it down with a brick (right); leave the weight in place for at least 24 hours until the sealant dries. That’s all there is to it.

3. Cracked Roof Shingles Repair

If a shingle is simply cracked or torn, you don’t have to replace it—just repair it. Start by applying a thick bead of roofing sealant under the crack. Press the shingle down and apply a second bead of sealant on top of the crack. Then spread the sealant with a putty knife.

The best part of this fix is that no one has to know you made it. It’s easy to camouflage: Check the gutter for an accumulation of colored granules that have washed down the roof from the shingles. Then gather some into a small cup and sprinkle them over the sealant to mask the repair.