What Is a Ridge Cap?

Along a ridge or hip, the field shingles from each side stop short of the line where the slopes meet. Ridge cap closes that gap. Each piece is bent over the peak, nailed on both sides, and overlapped so the next piece hides the nails of the one before it. Installers start at the end facing away from the prevailing wind so the exposed edges do not point into it. Purpose-made caps are thicker and pre-bent, while cut-down three-tab pieces give a flatter profile. Over a ridge vent, the cap also hides the vent and calls for longer nails.

Ridge and hip lengths are measured in linear feet, separate from the square count, so they get their own line on an estimate and their own number on an aerial measurement report. On a roof with many hips, that quantity is easy for a scope to understate. Ridges, hips, and edges take the hardest wind, so creased or missing cap pieces are a standard thing for a rep or inspector to photograph from a ladder or a drone.

Ridge cap and ridge vent get confused, but they are different parts. The vent is a slotted exhaust opening beneath; the cap is the roofing that covers it. Profile is the other trap. A thicker, high-profile cap changes the look of the ridge, and a homeowner who expected a flat line should hear that before the job, not at the final walkthrough.