Nails, Ridge & Flashing
The parts that get forgotten in the estimate and stop the job on the day.
The shingle bundles are the cheap part. The parts that make a roof watertight are sold separately, priced by the linear foot, and left off most estimates.
Drip edge
Metal L-flashing along every eave and every rake. The IRC has required it since 2012, and it is not optional at inspection.
It comes in 10 ft 6 in lengths and laps 2 inches at each joint, so a run of 10 ft 6 in of edge does not consume one length once you are past the first piece — count 10 ft 4 in of coverage per piece and add one.
Order of assembly matters and is routinely got wrong: at the eave, drip edge goes under the underlayment. At the rake, it goes over. Reverse it and water runs behind the fascia rather than off it.
Starter course
A dedicated product, with the sealant strip along the bottom edge where it can grab the first course of field shingles. Cut-up field shingles have the strip in the wrong place, and using them voids the wind warranty on most brands.
Sold in linear feet per bundle — usually 100 to 120 — and it runs along the eaves and, on most current specs, the rakes as well.
Hip and ridge cap
Also a separate product, and the one that most often runs short. A bundle covers 20 to 25 linear feet depending on the profile, and a hip roof has four hips plus the ridge to cover. Measure every hip; the ridge alone is half the number on most houses.
Flashing
Step flashing at every wall-to-roof intersection, one piece per shingle course. Counter flashing above it. Pipe boots per penetration, and the rubber collar on a cheap boot is the first thing on a roof to fail — usually at year twelve, on a shingle rated for thirty.
Nails
An 11 or 12 gauge, 3/8 in head roofing nail, long enough to penetrate the deck by 3/4 in or fully through the sheathing, whichever is less. Four nails per shingle in the field, six in high-wind zones and on steep slopes. That is roughly 320 nails per square at four, 480 at six — and about 2,000 nails to the 50 lb box.
The line to check before ordering
Whether the ridge is vented. A vented ridge changes both the cap count and the cut, and it is a decision that has to be made before the material list, not after the tear-off.
4 articles
Ridge Cap Shingles: Coverage per Bundle, and Why You Measure Hips TooRidge cap is sold in linear feet, not squares, and the number people get wrong is not the ridge — it is the hips.
Drip Edge: How Much You Need, Which Type Goes Where, and What It CostsDrip edge is cheap, required by code, and the piece most likely to be left off a re-roof quote. The length is easy; the type is where people go wrong.
Step Flashing: How Many Pieces, and Why Continuous Flashing FailsOne piece per shingle course. The count is arithmetic — the part worth knowing is why the cheaper alternative leaks.
How Many Roofing Nails per Square: Four, Six, and the Wind Rating in BetweenFour nails per shingle is 320 per square. Six is 480. Which one you need is decided by wind zone and pitch, not by preference.