How many roofing nails are in a pound?
Why counts vary
- Length: longer nails weigh more, so fewer fit in a pound.
- Gauge: 11 gauge shanks are thicker and heavier than 12 gauge.
- Coating: hot-dipped galvanizing adds more zinc, and weight, than electro-galvanizing.
- Head size: roofing nails have large heads, at least 3/8 inch under the residential code, which adds weight.
Hand nails vs coil nails
Professional crews mostly use coil nails in pneumatic nailers, sold by count rather than weight; a common box holds 7,200 nails in coils of 120. Hand-drive nails come in 1, 5 and 50 pound boxes.
How many pounds a roof takes
A metric architectural shingle roof needs about 64 shingles per square, the 100 square feet roofers price by. At four nails per shingle that is 256 nails per square, and six nails, used on steep slopes or for some warranties, makes 384. If your 1 1/4 inch nails run about 200 to the pound, that is roughly 1 1/4 pounds per square at four nails and closer to 2 pounds at six, before starter, ridge caps and waste. Multiply by the number of squares and add a margin.
Which nail length
Nails must reach at least 3/4 inch into wood decking, or through thinner decking, so length depends on the shingle thickness and layers at each spot. Ridge caps and doubled areas need longer nails than the field. Nail tips showing in the attic are normal when penetration is correct.