New guy is running a coil nailer on laminated shingles.

Three code/manufacturer violations in one setup:

1. Pressure too high (IRC R905.2.5 / Manufacturer specs): 110 psi is excessive for laminated/architectural shingles. Most manufacturers cap pneumatic pressure at 70–90 psi (often 80 psi max). High pressure drives heads through the top laminate into the fiberglass mat, destroying holding power and voiding the warranty. The "shining heads" on the course below are overdriven nails that punched through the shingle above.

1. Wrong nail location (IRC R905.2.5 / ASTM D3462): Nailing "an inch above the printed line" puts fasteners in the sealant strip (common bond area) or the double-thickness overlap zone. Correct zone: On the printed nail line (typically 5⅝"–5¾" from butt edge for laminates). Why it fails: Nailing high misses the two layers of shingle thickness below. You’re only grabbing one layer + deck. Pull-through resistance drops ~50%. It also prevents the sealant strip on the overlying shingle from bonding to a flat surface.

1. Exposed heads on course below = Through-penetration: Those shiny heads prove the nail blew through the full thickness of the shingle above. That shingle is now held by friction on the shank only—zero head bearing. Wind uplift will peel it instantly.

Fix now:

• Drop compressor to 80 psi (verify with gauge at tool).
• Set nailer depth so head sits flush with surface—countersunk = overdriven; proud = underdriven.
• Nail on the printed line, 1" from each edge, 1" above cutouts (4 nails/shingle min; 6 in high-wind zones per IRC R905.2.7.1).
• Hand-nail or replace every shingle with a shiny head showing below.

The issue is improper nail placement — specifically, nailing too high on the shingle, which violates manufacturer installation requirements and compromises roof integrity.

Laminated (architectural) shingles have a designated nail zone, typically marked by a printed nail line or a reinforced nailing strip, usually located 1 inch above the butt edge of the shingle and within 1 inch of each edge. Nailing above this line — as your coworker is doing by placing nails “about an inch above the printed nail line” — means the fasteners are landing in the unsealed portion of the shingle, often in the overlap area where the next course covers it.

This causes several problems:

1. Insufficient holding power: The nail is not penetrating through the shingle’s reinforcement layer (usually a double or triple layer in laminated shingles), reducing wind uplift resistance.
2. Exposed nail heads: As you observed, nails are visible on the course below because they’re driven too high — they’re not embedded in the shingle’s nailing zone and are instead protruding through the butt edge of the upper shingle, creating a leak path.
3. Voided warranty: Most manufacturers (e.g., GAF, Owens Corning, CertainTeed) require nails to be placed within the specified nailing zone. Nailing outside this zone voids the warranty.
4. Increased leak risk: Exposed nail heads can corrode, allow water ingress, and lead to premature deterioration.

Correct practice: Nails should be driven just above the adhesive sealant strip (not above the printed nail line), typically 1/2 to 3/4 inch above the butt edge, depending on the shingle model, and within the 1- to 2-inch-wide nailing zone marked on the shingle. The nail head should be flush with the shingle surface — not overdriven or underdriven — and never visible from the course below.

Action: Stop work immediately. Review the shingle manufacturer’s installation instructions (usually on the wrapper or website). Retrain the crew on proper nail placement. Use a nail gauge or mark the compressor regulator to ensure correct depth and placement. This is a workmanship issue, not necessarily requiring a licensed pro — but it must be corrected to avoid callbacks, leaks, and liability.