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Ridge cap and valley material are commonly under-ordered, leading to extra trips to the supply yard mid-job. This article shows how to measure linear feet of ridges, hips, and valleys directly from the roof plan, apply standard coverage rates (22-25 LF per ridge cap bundle, 50 LF per valley roll), and add a 10% waste factor for cuts. Includes worked examples for both gable and hip roofs and links to our Ridge Cap and Valleys calculators.
Ridge, hip and valley are all measured in linear feet, not squares, and they are the lines most often left out of an estimate that was worked from the area alone. On a hip roof they can add up to more length than the ridge itself.
| Ridge + hip length | Caps at 5 in exposure | Purpose-made bundles | Cut three-tab bundles |
|---|---|---|---|
| 20 ft | 48 | 1 | 1 |
| 40 ft | 96 | 2 | 2 |
| 60 ft | 144 | 3 | 2 |
| 80 ft | 192 | 4 | 3 |
| 100 ft | 240 | 5 | 4 |
| 140 ft | 336 | 7 | 5 |
| Valley length | 10 ft pieces at 6 in lap | Ice barrier at 36 in wide |
|---|---|---|
| 12 ft | 2 | 0.2 rolls |
| 20 ft | 3 | 0.3 rolls |
| 32 ft | 4 | 0.5 rolls |
| 48 ft | 6 | 0.7 rolls |
| 64 ft | 7 | 1 rolls |
Measure the valley along the valley line itself. It runs diagonally across two slopes, so it is always longer than the horizontal distance suggests.
Walk the perimeter of the roof with a sketch and write down every edge by name: ridge, each hip, each eave, each rake, each valley, each wall run. The area calculation buys the field. This list buys everything that keeps water out of it, and it is not derivable from the area at all.
Measure every ridge and every hip in linear feet. Purpose-made hip and ridge covers roughly 20 to 25 feet per bundle; three-tab cut into caps yields about 33. Add 10% for cuts and overlaps.
Yes, and on a hip roof the four hips together are usually longer than the ridge. Forgetting them is the most common shortfall in a cap order.
Along the valley line itself, from the eave to where it meets the ridge. It runs diagonally across two slopes, so it is always longer than the horizontal distance suggests.
Valley metal comes in 10 foot lengths lapping 6 inches, so each piece covers about 9.5 feet of run. Ice barrier at 36 inches wide covers about 66.7 feet of valley per roll.