How to Fix a Damaged Roof Shingle: Step-by-Step Guide

A single damaged or missing shingle is one of the best candidates for a DIY repair on a house. The job requires no special skills, costs $10 to $30 in materials, and can be completed in an hour.

A single damaged or missing shingle is one of the best candidates for a DIY repair on a house. The job requires no special skills, costs $10 to $30 in materials, and can be completed in an hour. Left unaddressed, even one missing shingle can allow water to reach the roof deck and cause rot, mold, and ceiling damage costing thousands to fix.

Assessing the Damage from the Ground

Before climbing onto the roof, do a ground-level inspection with binoculars or a zoom camera:

• Cracked or split shingle: Repair or replace depending on severity.
• Curling tabs: The shingle is drying out and nearing end of life. Reseal if isolated; plan for roof replacement if widespread.
• Missing shingle: Replace immediately — exposed felt and decking will absorb water with the next rain.
• Granule loss: Excessive granule loss (check gutters too — concentrated granule deposits indicate accelerating wear) means the shingles are aging out.
• Dark staining or sagging: Check from inside the attic — this indicates active moisture infiltration and may require more extensive repair.

What You Will Need

• Matching replacement shingles (bring a fragment for matching)
• Flat pry bar or shingle removal tool
• Hammer and 1-1/4 inch roofing nails
• Utility knife
• Roofing cement or asphalt mastic
• Caulk gun
• Rubber-soled shoes
• Safety rope and roof anchor (for pitches above 6:12)
• Chalk line or pencil

A roofing nail set of galvanized nails provides the corrosion resistance needed for long-term outdoor use.

Step 1: Safety Setup

Choose a day with no rain in the forecast and no frost on the roof surface. Wear rubber-soled shoes. Bring all materials in a bucket so you are not carrying items up and down the ladder.

On pitches above 5:12, attach a roof safety rope system to a ridge anchor point and attach your harness before ascending. This is non-negotiable for steep roofs.

Step 2: Remove the Damaged Shingle

Locate the nails holding the damaged shingle. Each shingle is nailed through the nailing strip, and the shingles above it are also nailed through the same strip — you will need to work around both.

Slide a flat pry bar under the damaged shingle and gently lift the tabs of the shingle above it to expose the nail heads. Remove the nails with the pry bar or hammer claw. Work carefully to avoid tearing the overlying shingles. Slide the damaged shingle out.

If the shingle is cracked but still fastened, it can sometimes be left in place and have the crack sealed with roofing cement rather than fully replaced — use this approach only if the shingle is otherwise in good condition.

Step 3: Inspect the Roof Deck

With the shingle removed, visually inspect the roof felt (tar paper) and the plywood or OSB deck underneath. The felt should be intact and dry. The deck boards should be firm — press firmly with your thumb and listen for any soft or spongy areas.

If you find soft decking (wood rot), cut out the damaged section with a circular saw and replace it before proceeding. Small rot areas can be treated with wood hardener if the decay is minor and the surrounding wood is solid.

Step 4: Slide In the New Shingle

Trim the new shingle to width if needed using a utility knife and straightedge. Slide it into position under the overlapping shingles above, aligning the lower edge with the course below. The shingle tabs should align with the offset pattern of the surrounding rows.

Step 5: Nail the Shingle

Drive four roofing nails into the nailing strip — the zone approximately one inch from the top of the exposed tab area. Nail placement should be near the four corners of the nailing strip. Drive each nail flush with the shingle surface — just until the nail head is flat. Do not overdrive (which breaks the surface) or underdrive (which creates a raised nail head that will catch on overlying shingles).

Step 6: Seal the Tabs and Nail Heads

Apply a small dab of roofing cement under each corner of the new shingle tab and press firmly. This bonds the adhesive strip of the overlying shingle to the new one and prevents wind uplift.

Apply a small bead of roofing cement over each exposed nail head. This prevents water from entering around the nail penetration.

Press the overlying shingles back down firmly. If the adhesive on the existing shingles has dried out, add roofing cement under those tabs as well.

Repairing a Cracked Shingle Without Full Replacement

For a shingle that is cracked but still in position:

1. Apply a bead of roofing cement under the crack, pressing the edges together firmly.
2. Apply a second layer of roofing cement over the top of the crack.
3. Sprinkle matching granules (save from old shingles or collect from gutters) over the wet cement to help the patch blend in and protect the mastic from UV degradation.

When to Call a Professional

• If you find water stains inside the attic directly below the repair area
• If multiple sections of decking are soft
• If the roof pitch is steep or the structure is more than one story
• If damage covers more than a small section — this signals the roof may need full replacement

Spot shingle repair is a genuine money-saver when executed on an otherwise sound roof. The key is catching the problem before a single missing shingle becomes a rot-damaged deck section.