How do you fix roof ridge capping?
Short answer. On an asphalt shingle roof, ridge capping is fixed by removing the damaged or missing cap shingles, checking the ridge vent and underlayment beneath, then installing new ridge cap shingles lapped in the same direction as the rest and nailed with nails long enough to reach the deck through the vent. Cracked caps are replaced, not glued, because they have lost their strength.
Why ridge caps fail first
- The ridge takes some of the strongest wind uplift on the roof.
- Caps are folded over the peak, so caps installed cold, or cut from thin 3-tab shingles, crack along the fold.
- Nails that are too short never reach the deck through a ridge vent.
- Hail strikes the ridge squarely.
The repair
- Work on a mild day; cold caps crack when bent and hot ones scuff.
- Remove damaged caps by breaking the seal and pulling their nails, along with the cap above that overlaps them.
- Inspect the ridge vent for damage and the underlayment for tears. Replace a crushed or cracked vent section.
- Install new caps starting from the end away from the prevailing wind, each overlapping the last at the manufacturer's exposure.
- Use nails long enough to penetrate the deck through the vent, placed where the next cap covers them.
- Seal the exposed nail heads on the final cap with roofing cement.
Matching and materials
Use the manufacturer's ridge cap shingles made for your shingle line when possible. They are thicker, often pre-bent, and designed to resist cracking, and some manufacturers require them for full warranty coverage. A slight color difference on an older roof is normal.
Tile ridge capping
On tile roofs, ridge caps are bedded in mortar or fixed over a ridge board with a ventilated membrane. Cracked mortar bedding is common; the repair is removing loose caps, rebedding them or switching to a mechanically fixed dry ridge system, and securing each cap.
See ridge vents vs box vents and wind damage to roofs in Georgia.