Replace a Single Damaged Shingle

A single torn or missing shingle compromises the entire waterproof membrane protecting your roof deck. Left unaddressed, that one gap invites water into the sheathing, where it spreads sideways under adjacent shingles and eventually drips into your attic. The good news: replacing one shingle is straightforward if you work carefully and understand how shingles overlap. Asphalt shingles lock together in a layered pattern where each course covers the nails of the course below. To remove one damaged shingle, you need to lift the ones above it without tearing them, extract the hidden nails, and reverse the process with a replacement. The work takes twenty minutes on a calm day with the right tools. The key is working gently and knowing exactly where those nails hide.

1. Pick the perfect temperature window. Choose a day between 50°F and 80°F to work. Shingles become brittle in cold weather and too flexible in extreme heat, both conditions making them prone to tearing when you lift them. Mid-morning on a mild day gives you pliable shingles that bend without breaking.
2. Break the adhesive seal gently. Gently slide the flat pry bar under the shingle directly above the damaged one, breaking the adhesive seal. Work slowly to avoid tearing. Lift just enough to expose the nails securing the damaged shingle — typically four nails in a line about six inches up from the bottom edge of the damaged piece.
3. Extract every single nail. Slide the pry bar under each nail head and lever it up while holding the overlapping shingle away with your other hand. You may need to lift the shingle two courses above to access the top row of nails. Pull each nail completely free — leaving broken shanks causes problems when you install the replacement.
4. Pull out the damaged piece. Once all nails are removed, pull the damaged shingle straight out from under the overlapping course above. If it resists, check for additional nails or adhesive. The shingle should slide free with steady, even pressure.
5. Slide the replacement into place. Round the back corners of the replacement shingle slightly with tin snips to help it slide under the course above. Slide it into position, aligning the bottom edge perfectly with the adjacent shingles on both sides. The vertical slots between tabs should line up with the pattern.
6. Secure with four perfect nails. Drive four roofing nails through the new shingle in the same position as the original nails, about one inch from each edge and six inches up from the bottom. Nail just until the head sits flush — overdriving creates dimples that collect water and underdriving leaves gaps.
7. Reactivate the waterproof seal. Lift the shingle above your replacement and apply a quarter-sized dab of roofing cement under each tab where it overlaps the new shingle. Press down firmly to reactivate the seal. Check the shingle two courses up and reseal any spots where you broke the adhesive.
8. Catch problems before they spread. Walk the roof section around your repair, checking for lifted tabs, exposed nails, or other damage you may have missed. Press down any loose edges and add small dabs of roofing cement where needed. Clear any debris from valleys and flashings.