What is ridge capping?
Short answer. Ridge capping is the final step of a shingle roof, when installers cover the peaks and hips with overlapping cap pieces nailed along the joint. Done right, each cap hides the nails of the one before it, laps away from the prevailing wind, and is fastened with nails long enough to reach solid wood.
The order of work
- Field shingles are run up both slopes and trimmed to meet near the peak.
- If the roof gets a ridge vent, the slot in the decking is cut open and the vent is nailed over it.
- Hips are capped first, from the bottom up, so the ridge cap later overlaps the tops of the hips.
- The ridge is capped from one end to the other, usually working away from the prevailing wind.
- The last piece is face nailed and the nail heads are sealed.
Details that separate good capping from bad
- Nail length: cap, vent and shingle layers add up, so the nails must be noticeably longer than field nails to reach through the deck. Short nails pull out in storms.
- Even exposure: each piece shows the amount the manufacturer specifies, so the sealant strips line up and grab.
- The right product: laminated architectural shingles crack if folded over a ridge, so manufacturers sell dedicated hip and ridge shingles.
- Cold weather care: caps can crack when bent in the cold, so careful crews keep them warm or wait for the afternoon.
When only the caps need work
Sometimes the caps fail alone: a few blow off in a storm, or the old caps cut from 3-tab shingles on an older roof split along the fold. Recapping can be a sensible repair when the rest of the roof is sound. If the field shingles are near the end of their life, though, new caps on an old roof are money better saved toward a replacement. Our ridge vent guide explains what often sits under the caps, and wind damage in Georgia shows why caps go first.