What is the difference between roof flashing and capping?
Short answer. Flashing is the metal or membrane that seals joints where the roof meets walls, chimneys, valleys and penetrations, steering water back onto the roof. Capping is the cover over the top of something: ridge capping covers the peak, wall capping or coping covers the top of a wall, and a chimney cap covers the flue; the two work together to keep water out of the joints.
Flashing seals the joints
- Step flashing and counterflashing where roofs meet walls and chimneys.
- Apron and headwall flashing where a slope meets a wall.
- Valley lining where two slopes meet.
- Drip edge at the eaves and rakes.
- Kickout flashing that turns water into the gutter.
Capping covers the tops
- Ridge capping: on shingle roofs, special hip and ridge shingles folded over the peak and over any ridge vent. On metal roofs, a formed metal cap with foam closures. On tile roofs, rounded ridge tiles bedded in mortar or fixed to a ridge system.
- Hip capping: the same idea along the sloped hips.
- Wall capping or coping: sloped metal or stone over the top of a parapet or masonry wall.
- Chimney cap and chase cover: the cover at the top of a masonry chimney or framed chase.
Why the difference matters for repairs
Water entering at a top, such as a ridge, chimney crown or wall cap, shows up in different places than water at a sidewall or valley. Ridge leaks often stain ceilings near the center of the house, while sidewall flashing leaks stain exterior walls. If a repair quote says flashing and capping, it should list which pieces, where, and whether they will be replaced or just resealed.