How to Replace a Damaged Asphalt Shingle Without Harming the Ones Around It
Break the seal, pull the nails above, slide the new shingle in and nail it where the next course hides the heads.
- Advanced
- 30 to 60 minutes per shingle
- Updated
The short answer
To replace a damaged asphalt shingle, lift the shingles above to break their sealant strips, pull the nails holding the damaged shingle and the row above it with a flat bar, slide the damaged piece out, slide a matching shingle into place, nail it with four roofing nails just under the overlying course, then hand seal the tabs with dabs of asphalt roofing cement. Do this only in dry, mild weather.
A single cracked, torn or missing shingle exposes the felt underneath, and in the wet Fraser Valley winter that is enough to let water through to the deck. Wind, branches, hail and old age are the usual causes. Replacing one shingle sounds easy, but it is a job of careful lifting: the shingles around it are sealed down, and the nails that hold the damaged one are hidden under the course above.
Done carefully, the repair disappears and the roof sheds water as before. Done roughly, you tear the neighbours, which turns one repair into three. If the damage covers a wide area or the shingles are brittle with age, a patch is often not the best answer. Read how to check your roof after a windstorm to judge the extent first, and see how to reseal lifted shingles if the shingle is merely loose, not broken.
This guide covers standard asphalt shingles. Because the work is on the roof surface, it carries real fall risk, and the honest answer for a steep or high roof is to have a roofer do it. For weaving a larger new section into an old roof, see how to tie in new shingles.
Tools
- Flat bar (small pry bar)
- Roofing hammer
- Hook blade utility knife
- Caulking gun
- Extension ladder with stabilizer
- Roofing harness, rope and anchor if the roof is steep or high
Materials
- Matching replacement shingles
- Galvanized roofing nails, 1-1/4 inch
- Asphalt roofing cement in a cartridge
- Spare pieces of shingle for scrap cuts
Safety first
- Do not go up on a wet, frosty or mossy roof. Wet granules and moss are as slippery as ice, and shingles in cold weather crack when bent.
- WorkSafeBC requires fall protection where a fall could be 3 metres (about 10 feet) or more. A second-storey eave or any steep roof needs a harness tied to an anchor, not just careful footing.
- Work with a spotter and a ladder that extends 3 feet above the eave, secured at the top. Never carry shingles up a ladder with one hand.
- Check for power lines near the eave or service mast before setting up a ladder.
Step by Step
Step 1: Choose dry, mild weather and set up safely
Shingles are stiff and brittle in cold weather, and the sealant strips do not grip well below about 10 degrees Celsius. A mild, dry day in spring or early autumn is the best time. Morning dew or overnight frost makes the surface slick, so wait until it has burned off.
Set the ladder on firm ground, extend it about 3 feet above the eave, and tie it off at the top if you can. If the roof is steep or the eave is above the first storey, this is a job for a roofer with proper fall protection.
Watch out: Never step on a shingle that is lifted or loose. It can slide out from under your foot.
Step 2: Identify exactly which shingle is damaged and how it is nailed
Shingles are nailed along a line just above the tab cut-outs or in the nailing zone on laminated shingles. Those nails are covered by the course above. The damaged shingle is held by nails in its own course and by the nails of the course above it that pass through its upper edge.
Take a good look at the shingle type. A 3-tab shingle is replaced as a whole tab strip or a cut tab. A laminated shingle is one piece with overlapping layers. Take a cracked piece down with you to match colour and profile at a supplier. Weathered roofs rarely match exactly, so choose the closest tone.
Step 3: Break the seal on the shingles above
Hold the shingle above the damaged one up with one hand and slide the flat bar under to free the sealant strip. Work slowly. Old sealant may stay glued, and a hard pull will crack the tab. A small putty knife helps separate a stubborn bond.
Do the same for the shingles to the left and right if their tabs overlap the damaged piece. Lift only enough to get the bar and your hand under. Bending a cold shingle back more than about 30 degrees can crack it.
Tip: On a warm day, shingles are pliable. In the heat of summer afternoon, asphalt can scuff easily, so do repairs in the morning.
Step 4: Pull the nails holding the damaged shingle
Slide the bar under the damaged shingle close to a nail head and lever it up until the nail comes free. Then reach under the lifted shingle above and pull its nails that pass through the damaged piece. Some installers slip the flat bar flat and drive the nail back down with a hammer tap until the head clears the shingle above, then pull it.
Pull every nail that sits in the footprint of the damaged shingle. Leaving a nail behind will puncture the new shingle or stop it from sitting flat.
Step 5: Slide out the damaged shingle
If the shingle is torn, it may come out in pieces. Clear all bits. Check the felt underneath for tears or soft wet patches. A tear in the felt needs a patch of roofing felt slid in under the course above, or at least a bead of roofing cement.
Look at the deck if it is visible. Dark, soft or spongy wood means water has been getting in for some time, and the deck needs a roofer's attention.
Watch out: If the deck feels spongy or you can see daylight through it, stop. The leak is bigger than one shingle.
Step 6: Slide in the new shingle
Trim the replacement to fit if needed with a hook blade knife, cutting from the back. Slide it up under the course above until the butt edge aligns with its neighbours. The exposure should match the rest of the roof.
Make sure the new shingle is tucked all the way up. If it sits low, it shows as a crooked line, and if it sits too high, the nails will not be covered by the course above.
Step 7: Nail the new shingle
Lift the course above and set nails in the manufacturer's nailing zone, usually just below the sealant strip on a 3-tab shingle and in the marked nailing area on a laminated shingle. Four nails is common for a standard shingle, but confirm on the bundle wrapper. Drive them straight and flush. A nail left proud lifts the shingle above, and a nail driven too deep cuts through it.
Take the time to match the pattern of the nails in the rest of the roof. See shingle nailing placement, count and depth for the detail.
Step 8: Hand seal the tabs
The original sealant strips will not reactivate without sun and heat, and the shingles you have just disturbed are not sealed. Apply a dab of roofing cement about the size of a quarter under each lower corner and press the tab down. Use small dabs. Too much cement squeezes out, collects dirt and can blister the shingle.
If the weather is cool, the hand sealing is what holds the shingle against wind until the sun sets the original strips. See how to reseal lifted or unsealed shingles for more on this.
Repairing a Missing Shingle in a Laminated Roof
Laminated (architectural) shingles have two layers laminated together, so a single tab is not cut out like a 3-tab. If the damage is a torn corner, a roofer will often replace the whole shingle. If you only have a section missing, you can sometimes slip a new full shingle in. Because each laminated shingle is nailed through a double-thickness nailing zone, getting the nails in the right spot matters even more.
When a Shingle Will Not Match
Shingles fade and granules wear. A brand new shingle against a fifteen year old roof will stand out for a couple of years. A dark or medium colour hides that better than a light one. If the roof is older and the pattern is discontinued, a roofer can sometimes pull a matching shingle from a less visible slope, such as the back of the house, and replace that with new material.
Common Mistakes
- Working on a wet or frosty roof. The surface is slippery and shingles crack when cold, which turns a small repair into a fall or a larger repair.
- Leaving old nails in place. They puncture the new shingle from below or stop it lying flat.
- Nailing in the wrong place. Nails too high miss the nailing zone and the shingle blows off, and nails too low end up exposed to the weather.
- Too much roofing cement. A thick smear collects grit, looks poor and can blister the shingle. Use small dabs.
- Skipping the felt check. A torn underlayment under a new shingle is a leak waiting for heavy rain.
- Patching an old, brittle roof. The shingles break when lifted, and each repair makes the next one harder. That is a sign the roof is near replacement.
When to Call a Professional
Call a roofer if the roof is steep, more than one storey high, wet or mossy, or if you do not have proper fall protection. Call one too if the shingles crack as you lift them, the deck under the damaged shingle is soft or stained, or the damage is not limited to one or two shingles.
A roofer will also look at why the shingle failed. A single blown-off shingle may just be wind, but repeated failures in the same area suggest poor nailing, a ventilation problem or an aging roof.
Fraser Roofing does free roof inspections across the Fraser Valley, from Hope to Abbotsford. See our Emergency Roof Repair service or the towns we cover.
How to Replace a Damaged Shingle: Questions
Can I replace just one shingle on my roof?
Yes. One damaged asphalt shingle can be replaced without touching the rest. You lift the shingles above to break their sealant, pull the nails, slide out the damaged piece, slide in a new one, nail it and hand seal the tabs. The challenge is doing it without tearing the neighbouring shingles, which is harder on old, brittle roofs.
How many nails go in a replacement shingle?
Four nails per shingle is common for standard slopes, placed in the nailing zone marked on the shingle, but some manufacturers and steep or high wind areas call for six. Always check the installation instructions on the bundle wrapper. The nails must go straight and flush, through the nailing zone, so the course above hides the heads.
What temperature is too cold to repair shingles?
Below about 10 degrees Celsius, shingles become stiff and can crack when lifted, and the sealant strips will not bond well. A cool dry day can still work if you handle the shingles gently and hand seal them, but mild weather above 10 degrees is best. Never work on a frosty or wet roof.
Do I need roofing cement when replacing a shingle?
Yes, in most cases. You have broken the factory seal on the shingles you lifted, and the new shingle has not had sun to activate its own strip. Small dabs of asphalt roofing cement under the tab corners hold them against wind until the sun and heat reseal them. Use dabs about the size of a quarter, not a smear.
Will a new shingle match my old roof?
Rarely exactly. Sun and weather fade shingles and wear off granules, so even the same product looks brighter for the first year or two. Take a piece of the old shingle to the supplier to match colour and profile. If the roof is old and the pattern is discontinued, it may be worth taking a shingle from a hidden slope.
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This guide is general education. Always follow the product manufacturer's installation instructions, the BC Building Code and WorkSafeBC requirements, which take priority over anything written here.
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