How to Replace Blown-Off or Damaged Ridge Cap Shingles
Start at the downwind end and lay toward the wind, nail where the next cap covers the heads, and seal the last one.
- Advanced
- 2 to 4 hours
- Updated
The short answer
To replace blown-off ridge cap, remove the damaged caps, check the ridge deck and the field shingles below, start at the end of the ridge away from the prevailing wind and lay toward it, bend each cap over the ridge, fasten with two nails per cap about 1 inch above the exposure line and 5/8 to 1 inch in from each side, and hand seal the final cap with roofing cement. Only work on a dry, calm day with fall protection.
Ridge caps are the small shingles that bend over the peak of the roof and cover the top edge of the field shingles on both sides. They take the strongest wind on the whole roof, and in the Fraser Valley, a strong storm is often enough to lift or tear off a few at the end that faces the wind. With the caps gone, the top of the roof is open to rain, and the ridge is also where the last rows of shingles end, so water can easily get in.
Repair is a matter of removing the damaged caps, fitting new ones in the right sequence, and fastening them so the wind cannot lift them again. The sequence matters: each cap covers the nails of the one before it, so you start at the end away from the prevailing wind and lay toward it, which leaves the wind blowing over the laps, not into the exposed edges. If you have a ridge vent, the caps also cover it, see how to install a ridge vent.
Because the work is at the peak, a fall is a serious risk. If you cannot work with proper fall protection, hire a roofer. Start by checking the damage from the ground, see how to check your roof after a windstorm.
Tools
- Roofing hammer
- Flat bar
- Hook blade utility knife
- Caulking gun
- Chalk line
- Extension ladder with stabilizer
- Roofing harness, rope and roof anchor
Materials
- Hip and ridge cap shingles, matched to the roof
- Galvanized roofing nails, long enough to penetrate the deck, commonly 1-1/2 inch or longer
- Asphalt roofing cement
- Ridge vent material, if the ridge is vented, per the manufacturer
Safety first
- The ridge is the most exposed part of the roof. WorkSafeBC requires fall protection where a fall could be 3 metres (about 10 feet) or more, and on a ridge you need a harness tied to an anchor, not just a ladder.
- Do not go on the ridge in wind. A gust at the peak can knock you off balance, and cap shingles in the air are hard to control.
- Work on a dry roof only. The ridge is steep on both sides, and a slip has nowhere to stop.
Step by Step
Step 1: Assess the damage and choose a calm, dry day
Count the missing and damaged caps and note where the damage starts. Also look for exposed nails, torn field shingles next to the ridge and any bare wood. Plan for the work to take longer than you expect, since setting up safe access is part of the job.
Do not work if rain or wind is forecast, because the ridge will be open while you work.
Watch out: If you do not have a harness and a proper anchor, this job is for a roofer.
Step 2: Get up safely and anchor yourself
Set the ladder with a stabilizer and climb with three points of contact. Install a roof anchor into the rafters on the slope, following its instructions, and connect your harness. Work from the slope, not by straddling the ridge. See how to install a roof anchor and how to fit a fall arrest harness.
Step 3: Remove the damaged and loose caps
Lift each cap gently to release its seal and pull the nails that hold it. Remove caps back to a point where they are sound and still well sealed. Do not leave a loose cap in place, since it will catch the wind again.
Keep the pieces in a bucket so they do not slide down the roof, and so you can check the size and type of the old caps for matching.
Step 4: Inspect the ridge and the field shingles below
Look for torn or missing field shingles near the peak, rusted nails and gaps. Replace any damaged shingle first, see how to replace a damaged shingle. Check that the deck at the ridge is solid and that any ridge vent material is in place and undamaged.
Step 5: Choose the starting end and snap a guide line
Each cap overlaps the one before it, so the exposed edges all face the end where you started. Start at the end away from the prevailing wind, the downwind end, so the exposed edges face away from the wind and cannot be lifted. Check which way wind usually hits your ridge, since it varies with the site and the season, or follow the direction printed on the bundle wrapper. A chalk line along each side at the cap width keeps them straight.
Match the cap size and colour. Caps can be cut from three-tab shingles, or bought as purpose-made hip and ridge cap, which is thicker and holds better in wind.
Step 6: Bend and lay each cap over the ridge
In mild weather the caps bend easily, and in cold they crack, so warm them in the sun first. Centre the cap so both sides overhang equally. Exposure is how much of each cap is left showing, and it is commonly about 5 to 5-5/8 inches, but confirm on the wrapper. Keep it consistent along the ridge.
Step 7: Nail each cap in the correct spot
Use nails long enough to pass through all layers and into the deck, commonly 1-1/2 inches or longer for caps. Place them where the next cap covers them, following the manufacturer's diagram. Drive them flush, not overdriven. Two nails per cap, one on each side, is the usual pattern, and more may be needed in high wind areas, so check the instructions.
If the ridge is vented, the nails must be long enough to reach through the vent material and into the framing, see how to install hip and ridge cap.
Step 8: Seal the last cap and any exposed nails
The last cap has no cap over it to hide its nails, so they are exposed. Place two nails near the edges and cover each head with a generous dab of roofing cement, pressed smooth. Also add small dabs of cement under the edges of the caps to hold them until the sun seals the factory strips.
Check the whole ridge for a straight line and no loose edges before you climb down.
Ridge Cap Products
Purpose-made ridge cap shingles are thicker and pre-bent, which lets them hold up better in wind and gives a fuller profile than cutting three-tab shingles. Some manufacturers require their own cap product to maintain warranty coverage. Match the colour as closely as you can, knowing that new caps will look brighter than weathered ones for a year or two.
Ridge Caps and Wind
Caps that blow off once often do so again if the cause is not fixed. Common causes are nails that were too short or too few, caps laid starting at the wind end, so the exposed edges face into the wind, old caps that have lost their seal, and caps bent in cold weather that cracked. A properly nailed and sealed ridge holds in most storms.
Common Mistakes
- Starting at the wrong end. If you start at the wind end, the exposed edges face into the wind, which gets under them and lifts them off.
- Nails that are too short. They do not reach the deck through the layers, and the caps pull off.
- Bending cold caps. They crack along the fold and fail in the next wind.
- Leaving the last cap's nails exposed and unsealed. They become a leak path and the cap works loose.
- Working without fall protection. The ridge is the most dangerous part of the roof.
- Not checking the field shingles below. Damage next to the ridge will leak even with new caps.
When to Call a Professional
Call a roofer if the roof is steep or high, if you do not have fall protection or an anchor, if there is damage to the deck or the field shingles, or if the ridge is vented and the vent material is damaged. The ridge is the place where a mistake can cost the most, in safety and in leaks.
If caps keep blowing off, a roofer can check the nailing and the cap product, and often finds an installation fault that simply replacing them will not cure.
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 Blown-Off Ridge Cap: Questions
Why did my ridge cap blow off?
The ridge takes the strongest wind on the roof. Caps blow off when they were nailed with too few or too short nails, laid with the exposed edges facing the wind, bent in cold weather so they cracked, or when the factory seal has weakened with age. A strong storm in the Fraser Valley is often enough to lift a few.
How many nails does a ridge cap shingle need?
Usually two per cap, one on each side, placed about 1 inch above the exposure line (about 6 inches back from the exposed edge on a 5 inch exposure) and 5/8 to 1 inch in from the side, so the next cap covers the heads. The nails must be long enough to go through all the layers and into the deck, commonly 1-1/2 inches or longer. Always confirm the pattern on the manufacturer's instructions.
Which way do you lay ridge cap shingles?
Start at the end of the ridge away from the prevailing wind, the downwind end, and lay toward the wind. Each cap overlaps the previous one, so the exposed edges face the end where you started, and the wind then blows over the laps instead of into them. Check which way wind usually hits your ridge, or follow the direction on the bundle wrapper.
Can I use regular shingles as ridge cap?
Three-tab shingles can be cut into cap pieces, and it is done, but purpose-made hip and ridge shingles are thicker and pre-bent, so they hold up better in wind and give a fuller look. Some manufacturers require their own product to keep warranty coverage. Check the instructions for your roof.
Is a missing ridge cap an emergency?
It should be treated as urgent. With the caps gone, the top of the roof is open, and rain can get in where the field shingles meet. A temporary cover may help if it can be put on safely in calm weather. Do not go up in wind or rain, and book a roofer for a proper repair soon.
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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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