An 8-penny nail (8d) is a hand-driven or collated nail that’s 2½ inches long, widely used for framing, sheathing, and subfloor fastening.
Plain Answer With Real-World Context
The “8d” label tells you two things: the nail’s penny size and its typical length. In modern practice, 8d equals 2½ inches. The shank is often about 0.131 inches for “common” nails, with a full round head that holds panels and lumber tight. You’ll also see 8d sinkers with a thinner shank and slightly shorter length for easier driving, especially into dense studs.
8-Penny Nail Size And Uses At A Glance
| Penny Size | Nominal Length (in.) | Typical Uses |
|---|---|---|
| 2d | 1 | Small crafts, light trim |
| 3d | 1¼ | Stops, bead molding |
| 4d | 1½ | Paneling, thin trim |
| 5d | 1¾ | Light casing, lath |
| 6d | 2 | Baseboard, light framing aids |
| 7d | 2¼ | Light sheathing, furring |
| 8d | 2½ | Stud-to-plate, wall and roof sheathing, subfloor |
| 9d | 2¾ | Decking and siding patterns |
| 10d | 3 | Heavier framing, stair stringers |
| 12d | 3¼ | Ledger aids, thicker stock |
| 16d | 3½ | Heavy framing, plates and headers |
| 20d | 4 | Timber fastening |
| 30d | 4½ | Heavy nailing where length matters |
| 40d | 5 | Large timbers and blocking |
| 50d | 5½ | Timber work, specialty |
| 60d | 6 | Timber work, specialty |
That quick map puts 8d right in the sweet spot for general carpentry. It’s long enough to reach through sheathing and bite well into studs or joists, yet short enough to keep splits under control in most SPF or similar lumber.
What Does 8d Nail Mean?
Builders write nail sizes with a number plus the letter “d,” so 8d reads “eight-penny.” The “d” traces back to English usage where pennies were the pricing shorthand for bundles of nails, and “d” connected to the old denarius mark. Today, the mark remains a length tag in North America. When you see 8d on a box, expect a 2½-inch nail unless the carton clearly calls it a sinker or box pattern.
Specs That Matter On An 8d Common
An 8d common nail pairs a full round head with a stout shank. Typical dimensions are 2½ inches long, about 0.131 inches in diameter, and a head near 9⁄32 inch. That blend drives well with a smooth face hammer or a framing gun using matching collated nails. Full heads help panels resist pull-through, which is why codes and plans so often call out “8d common” for wall and roof sheathing schedules.
8d Sinker Versus 8d Common
Sinkers cut friction. Most 8d sinkers run 2-3⁄8 inches long with a thinner shank and a textured, slightly smaller head. Many carry a vinyl or cement coating to help the nail slide and then grip. On tight stud bays, that tiny change saves bent nails and keeps the pace up. If your schedule says “8d common,” don’t swap in a thin sinker unless the spec or inspector allows it. They’re cousins, not twins.
Shank Styles You’ll See
Smooth shank: classic, fast to drive. Ring shank: raised ridges that resist withdrawal in sheathing, subfloors, and siding. Spiral shank: twists as it drives, biting into grain and holding well in softwoods. Pick the shank for the job and the substrate, not just what’s in your apron.
Where An 8-Penny Nail Shines
Framing: Stud-to-plate, blocking and trimmers all suit 8d, especially when plans call for closer nail spacing. Sheathing: With plywood or OSB, 8d nails bring reliable bite without over-penetration through panel faces. Subfloors: Pair 8d ring shanks with adhesive to quiet floors. Deck projects: Use coated or stainless 8d where corrosion can attack fasteners.
When To Grab 6d Or 10d Instead
Use 6d for thin stock and delicate trim where splits can ruin a board. Step up to 10d when you need a longer reach or when a detail calls for more embedment. Framing anchors and straps may specify a different nail pattern entirely; follow those printed callouts without substitutions.
Code Notes And Reference Guides
If your plan set lists “8d common,” match the head and shank, not just the length. Code tables and engineered guides treat head size as part of the fastener design. For quick dimensions across common nails, see the dimensions of standardized nails. For fastening behavior in wood—withdrawal, lateral loads, and shank effects—browse the USDA Forest Products Laboratory’s Wood Handbook: Chapter 8, Fastenings. For tool and nail families, head sizes, and collated equivalents, see Simpson Strong-Tie’s fastener overview for nails. Hardware packaging also lists exact nail specs for each connector; follow those labels to the letter.
Taking An 8 Penny Nail From Box To Board
Before you swing, match the nail to the wood, the exposure, and the tool. SPF framing accepts smooth or ring shanks; dense engineered studs benefit from sinkers or gun nails with slick coatings. Outdoor builds need corrosion-resistant plating or stainless. Grab the right driver face too—smooth for finish-sensitive areas and milled for speed on rough framing.
Length And Embedment
A useful rule is two-thirds embedment into the bearing member. A 2½-inch 8d through ½-inch sheathing sinks about 2 inches into the stud, which meets that rule and leaves a stout bite. If you stack layers—say, foam plus sheathing—check that remaining embedment still lands near that mark, or pick a longer nail where allowed.
Head Style And Pull-Through
Full round heads spread load over a wider circle. That helps prevent pull-through on panel edges under wind or racking. Smaller heads on some sinkers can leave less bearing on thin panels. When in doubt, follow the table on the plan or the label on the connector; those numbers assume a certain head.
Shank Pattern And Holding Power
Ring shanks grab fibers and resist working loose from vibration or moisture cycling. In subfloors, that grip pairs well with adhesive to limit squeaks. Smooth shanks drive fast and are easy to pull during adjustments, which suits first-fit framing. Spiral shanks are handy in soft framing where split risk is low and withdrawal needs a bump.
Material And Coating Choices
Bright steel: for dry interior framing. Electro-galvanized: light zinc layer for mild moisture. Hot-dip galvanized: thick zinc for exterior framing and treated lumber. Stainless: long-term durability in coastal air, pool houses, or cedar and redwood. Treated lumber chemicals are tough on bare steel, so match the coating to the wood treatment tag.
Hand-Driven Versus Gun Nails
Hand nails are easy to source in small boxes and suit punch-list work. Collated 8d nails keep pace on big runs of sheathing and floors. Stick with the shank and head your schedule calls out, even when you switch between tools. Manufacturers publish equivalency notes so your gun nails meet the same dimensions as the hand-drive spec.
Fit, Finish, And Workmanship
Drive nails flush with the surface of the panel or wood, not proud and not over-driven. Over-driving weakens panel edges and can void shear values. Pre-drill near board ends when you face a split risk. Keep nail lines straight and spacing true to the plan; clean rows help panels share load and make inspections go faster.
Safety And Good Practice
Wear eye protection, set a firm stance, and keep hands out of the path. On ladders or scaffolds, stage fasteners in a pouch to avoid juggling boxes. When pulling nails, use a block under your hammer or cat’s paw to protect the wood. Box up bent nails and spent strips so nobody steps on a surprise.
8d Nail Variants Worth Knowing
| Type | Nominal Dimensions | Best For |
|---|---|---|
| 8d common | 2½ in. × 0.131 in. | Framing, wall and roof sheathing |
| 8d sinker | 2-3⁄8 in. × 0.113–0.131 in. | Dense studs, fast production nailing |
| 8d ring shank | 2½ in. × 0.131 in. ring | Subfloors, panels that see movement |
| 8d hot-dip galvanized | 2½ in. × 0.131 in. | Exterior framing, treated lumber |
| 8d stainless | 2½ in. × 0.131 in. | Coastal air, cedar, redwood |
| 8d box | 2½ in. × 0.113 in. | Thinner boards where split risk rises |
Comparing 8d To Neighbor Sizes
6d (2 in.) seats trim and thin stock with less split risk. Nail guns also run 2-inch collated strips for panel nailing where plans allow. 10d (3 in.) adds reach and deeper embedment in framing. 16d (3½ in.) is the go-to for heavy studs and plates. Those leaps let you tune holding power, reach, and split risk to the material in front of you.
History And Naming
Penny sizes started as a pricing shorthand on nail bundles in England. Over time, the tag stuck as a length cue rather than a cost. The “d” stayed with it, carried over from older money marks. That’s why you still read 8d, 10d, or 16d on boxes today. It’s a handy code, and once you learn a few anchor sizes from memory, you can pick the right box in seconds.
Nail Gauge, Head Size, And Wood Behavior
Shank diameter affects both withdrawal and split risk. A thicker shank bites harder but stresses end grain more. Head size affects bearing on panels; larger heads resist pull-through on edges and seams. Lumber species matters too. Spruce and pine welcome a stout 8d common in most spots. Dense LVL, LSL, or specialty studs may favor a slick sinker to avoid bent nails and wasted time. When you can, make a quick test on a cutoff before you run a full wall.
When Nails Are Better Than Screws
Nails shine when the joint needs a bit of give. Wood moves with seasons, and nailed shear walls and roof decks rely on that slight flex. Screws offer strong withdrawal resistance, yet plain framing often calls for nails because they seat fast and share load well across many fasteners. Use screws where the detail calls for them, such as ledger connections and specialized hardware. For everything else on the stud line, 8d nails keep the pace steady and the schedule on track.
Tool Setup And Driving Technique
Set nail gun pressure so heads end up flush with panel faces. Keep your stance square to the line, choke up on the hammer for control, and let the weight do the work. Two light taps to start, one firm swing to seat. On gun work, keep strips fresh and the nose square to the surface to avoid angled entries and blow-outs.
Gun Depth Dial-In
Run a short test strip, adjust depth until heads sit flush across the panel.
Common Mistakes To Avoid
Mismatched fastener: Substituting thin sinkers for a common nail where a table expects a larger head can erode panel performance. Over-driving: Buried heads reduce bearing on panel edges. Under-driving: Proud heads snag housewrap and siding. Wrong coating: Bright steel in damp spaces rusts fast and stains nearby wood.
A Quick Inspection List
Check the label: “8d common” means full head and the right shank. Confirm length: 2½ inches for the hand-drive spec. Scan rows for spacing and straight nail lines. Check panel edges for flush heads. Match coatings to lumber tags. If you switched to collated strips, confirm the head and shank match the spec sheet for the gun nails you loaded.
Quick Recap
An 8-penny nail is the 2½-inch staple of framing and panel fastening. Choose common for broad head bearing, sinker for speed into hard stock, and ring shank when you need gripping power. Match coatings to exposure, and match the head and shank to what the plan demands. Do that, and you’ll get tight panels, quiet floors, and clean inspections every day from the first swing to the last nail set.