What are the dimensions of metal ridge cap?
Short answer. Metal ridge cap is usually sold in pieces about 10 feet long, and its other dimensions, the leg width on each side, the overall girth and the bend angle, depend on the panel profile and roof pitch. The cap's legs must be wide enough to cover the top of the panels and the closure strips, so it should come from the same manufacturer and profile as the panels.
The dimensions that matter
- Length: standard pieces are about 10 feet. Some suppliers add a few inches so the stated coverage still holds after laps.
- Leg width: how far the cap reaches down each side of the ridge. It has to cover the closure strip and lap well over the top ends of the panels.
- Girth: the total flat width of metal before bending, which suppliers use to price trim.
- Bend angle: caps are formed to a pitch or made adjustable. A cap bent for 4 in 12 will gap on a 10 in 12 roof.
- Hems and profile: hemmed edges add stiffness and hide raw metal; some caps have a raised center or roll.
Plain cap versus vented cap
A plain ridge cap seals the ridge solid. A vented ridge uses either vented closure strips under a standard cap or a cap with a built-in vent profile, and needs a slot cut in the deck to let attic air out.
Standing seam ridges
Standing seam caps are usually custom bent to the roof pitch and attached to Z-closures rather than screwed through the panels, so their legs and hems are sized to the closure system.
Measuring before you order
- Measure the ridge length and add the overlap at each joint, usually several inches, plus the end treatments.
- Note your roof pitch on each side, which may differ.
- Check the panel profile name, since closures and caps are matched to it.
- Match the color and coating to the panels.