1-1/4" Coil Roofing Nails: For Re-Roofs and Thick Shingles

The 1-1/4" coil roofing nail is what you reach for when 1" isn't long enough but you don't yet need a 1-3/4" structural fastener. The two most common scenarios: re-roofing over an existing layer of shingles (where local code permits it), and installing modern thick architectural shingles like CertainTeed Landmark Premium or GAF Timberline UHDZ that approach 3/8" of laminate stack-up.

Most production crews stock both 1" and 1-1/4" coils on the truck for exactly this reason — the depth adjustment on the gun does most of the work day to day, but length is fixed by the box you load.

When to use 1-1/4" coil nails

Use 1-1/4" for: re-roof-overs (one existing layer of shingles still on the deck, where code permits), thick architectural and luxury shingles, ridge cap installations on premium shingle lines, decks where you want more pull-out resistance in high-wind zones, and 5/8" plywood decks where 1" may shy of the 3/4" penetration minimum after underlayment is accounted for.

Don't use 1-1/4" for: standard new construction with a single underlayment over 1/2" plywood (1" is plenty and cheaper), or any application where the nail would protrude through 1x board sheathing — the exposed point inside the attic causes both code issues and homeowner complaints when they spot it from below.

The re-roof-over math: if you're nailing through a new shingle (1/4"), one existing shingle layer (1/4"), an underlayment (1/16"), and you need 3/4" of penetration into 1/2" plywood, you need a minimum of 1.18" — call it 1-1/4" with a small safety margin. This is why 1-1/4" is the standard re-roof-over nail in jurisdictions that still permit overlays.

Pricing reality: expect to pay roughly 12-18% more per nail than 1" simply because you're using more steel. A 7,200-count box of 1-1/4" hot-dip galvanized is available at competitive pricing in 2026.