A ridge cap order needs three numbers on the record: the measured ridge-and-hip length, the chosen product's coverage per bundle, and a stated waste allowance. The ridge cap measuring guide gives you the first, the ridge cap product guide gives you the second, and this page works through the third and the full order math.
Keep the measured length and the allowance on separate lines. A single combined number cannot be rechecked, and rechecking is how a short order gets caught before delivery day.
What does a ridge cap order contain?
Five lines: the measured length, the allowance, the rounded order quantity in the supplier's selling unit, the product and color details, and the delivery check. Write the allowance beside the measured number so a later check can separate what was measured from what was added.
Write "94 lin ft measured + 10% allowance = 103.4 lin ft order" rather than recording 103.4 lin ft alone. A single number cannot be rechecked.
How do you turn the measured length into bundles?
Multiply the measured length by 1 plus the allowance written as a decimal, then divide by the product's coverage per bundle and round up. A 10% allowance becomes a multiplier of 1.10.
Bundles = measured length × (1 + allowance %) ÷ coverage per bundle, rounded up
Use the coverage figure printed for the product you chose, not a memorized rule. Preformed cap bundles cover 20 to 33 lineal feet depending on the product and the installed exposure, per GAF's product guidance. Calculator pages that quote one bundle per 35 feet or 20 feet state rules of thumb for no named product. The data sheet for the product on your order controls the count.
What waste allowance fits your roof?
Match the allowance to the roof's cuts. Hips need angled cuts and a starter piece at each run, and every cut wastes part of a cap piece. A straight gable ridge needs little more than end cuts.
| Roof shape | Allowance | Why |
|---|---|---|
| Simple gable, one straight ridge | 10% | End cuts and one starter piece only |
| Hip roof | 10 to 15% | Angled cuts at every hip, starter pieces at each run |
| Complex: dormers, valleys, multiple ridges | 15% | Short runs and transitions multiply the cuts |
Order from one color lot at order time. A second delivery from a different lot can shade differently across the ridge, where every cap sits in full view.
What does the order math look like?
Take a gable roof with a 36 ft ridge, ordered in GAF TimberTex caps: 30 pieces per bundle, 8 in exposure, 20 lin ft per bundle.
- Choose the allowance. One straight ridge with two end cuts fits 10%.
- Convert to a multiplier: 1 + 10 ÷ 100 = 1.10.
- Multiply: 36 × 1.10 = 39.6 lin ft.
- Divide by the product's coverage: 39.6 ÷ 20 = 1.98 bundles.
- Round up to whole bundles: 2 bundles.
Result: the order line reads 2 bundles of TimberTex, with 36 lin ft measured and a 10% recorded allowance.
Cross-check by pieces. At 8 in exposure each piece covers 2/3 ft, so the order needs ceil(39.6 ÷ 2/3) = 60 pieces. Two bundles hold 2 × 30 = 60 pieces. The piece count agrees, which is how you catch a coverage figure read for the wrong product.
| Measured length (lin ft) | With 10% allowance | Bundles to order |
|---|---|---|
| 50 | 55.0 | 3 |
| 75 | 82.5 | 4 |
| 100 | 110.0 | 5 |
| 125 | 137.5 | 6 |
How do you order metal ridge cap?
Order metal caps by the piece, not the bundle. The cap must come from the same panel manufacturer, matched to the panel profile, gauge, and color. Profile-matching closure strips sit between the panel and the cap on each side of every ridge and hip run, and the panel manufacturer's trim detail sets the piece length and the closure requirement.
Count whole pieces: pieces = ceil(run length ÷ piece length), rounded up. A 40 ft ridge run with 10 ft cap pieces takes 4 pieces. Add closure strips for both sides of each ridge and hip run, plus the fasteners the manufacturer detail calls for. Confirm the trim detail for piece laps before you count, because piece lengths and joint details vary by manufacturer.
How do you order field-cut 3-tab caps?
Count whole shingle bundles. Cutting one 12 by 36 in 3-tab shingle into three 12 in pieces at 5 in exposure gives about 33.75 lin ft per bundle of 27 shingles. Shingle counts vary by product, so treat this as an estimate and check the wrapper before you commit to it.
Order the same color as the field shingles, in one lot. GAF notes that caps were historically cut from 3-tab strip shingles, and 3-tab shingles remain the easier stock to cut cleanly because laminated shingles are thicker.
What goes on the supplier order?
- The product name and profile, with the color.
- The coverage or pieces per bundle from the label, and the exposure that figure assumes.
- The bundle count, with the piece-count cross-check beside it.
- Starter pieces or closure strips, counted separately from the cap bundles.
- The ridge vent model when a vent shares the ridge line, so the caps clear it.
- The delivery date and who checks the ticket.
Check the delivery ticket against the order before the driver leaves: product, color, and bundle count. The ticket is the record of what arrived.
Common ridge cap ordering mistakes
- Ordering the measured length with no allowance, then shorting the last run.
- Using another product's coverage figure for the product you bought.
- Rounding bundles down to save one bundle.
- Recording the allowance inside the measured number so the order cannot be checked.
- Measuring the ridge and forgetting the hips.
- Copying a memorized bundles-per-foot rule instead of the label figure.
- Leaving closure strips and fasteners off a metal cap order.
- Placing a second delivery from a different color lot.
Sources and scope
- GAF, All about Hip and Ridge Cap Shingles: product lineup, the 20 to 33 lineal feet per bundle coverage range, Seal-A-Ridge piece and exposure figures, and warranty eligibility. Manufacturer. Accessed 2026-10-19.
- GAF, Seal-A-Ridge Sell Sheet, RESHR112-1124 (dated 01/2025): 45 pieces per bundle, 6 2/3 in exposure, 25 lineal feet per bundle. Manufacturer. Accessed 2026-10-19.
- Owens Corning, ProEdge Hip & Ridge Shingles data sheet: 66 pieces per bundle, 6 in exposure, 33 lineal feet per bundle. Manufacturer. Accessed 2026-10-19.
- Home Depot product listing quoting GAF TimberTex specifications: 30 pieces per bundle, 8 in exposure, 20 lineal feet per bundle. Retailer quoting the manufacturer. Accessed 2026-10-19.
- Rollforming Magazine, Closure Strips: Preventing Big Problems: closure strip types and placement between panel and cap. Trade publication. Accessed 2026-10-19.
- EngineerFix, How to Install and Maintain a Metal Roof Ridge Cap: cap profile matched to the panel profile, profile-matching closure strips, sealant under the cap. Contractor source. Accessed 2026-10-19.
- EngineerFix, How Many Ridge Cap Shingles Are in a Bundle? and How Many Linear Feet Does a Bundle of Ridge Cap Cover?: waste ranges of 5 to 15% with 10% as a safe default, and the round-up-to-whole-bundles practice. Contractor planning sources; figures are unattributed planning conventions. Accessed 2026-10-19.
Scope: product figures come from the manufacturer sources listed, directly or quoted by retailers. Coverage and bundle counts change by product line and revision; the current data sheet controls the figures on a real order. The 3-tab bundle figure is derived planning arithmetic, not a manufacturer statement. Quantity planning does not select the product, certify wind or warranty terms, or make ridge work safe; the data sheet, the manufacturer's instructions, and the crew's fall protection plan control those decisions.
Review responsibility: Saleem Sial owns the published calculation, source, and editorial checks. Waseem Sial, External Reviewer and Engineer, remains listed for ongoing external review; no completed external-review date is claimed.
Next, read the ridge cap measuring guide to get the measured length, the ridge cap product guide to lock the product, the roofing waste allowance guide for the allowance method, or return to the Roofing Quantity Planning hub.
