A leaking roof can be a headache for many owners. In addition, a leaking roof can cause extensive water damage inside a home, potentially damaging the foundation. A shingle roof is simple to repair. Locate the damaged shingle on a rooftop, and pull back the shingles above it. Using a claw hammer, remove the nails holding in the damaged shingle. Check for any existing damage to the tar cover. If there is any damage, repair it with silicone or roofing tar. Place the new shingle under the existing roof shingles, and nail in place. Make sure no other shingles were dislodged.