Simpson 12d x 3-1/4" Preservative-Treated Wood Decking Nail in Type 316 Stainless Steel is a high-performance exterior fastener engineered by Simpson Strong-Tie for deck and dock construction. Featuring an annular-ring shank and a full round checkered head, this nail delivers superior holding power and long-term corrosion resistance in outdoor environments where pressure-treated lumber and moisture exposure are constant challenges. The 9-gauge, 0.148" shank diameter is specifically sized to drive cleanly into both green and seasoned preservative-treated pine, making installation straightforward whether you are building a new deck, replacing damaged boards, or constructing a dock near salt water. With Type 316 stainless steel construction, this fastener is the right choice for coastal and high-humidity applications where standard galvanized nails would corrode prematurely.

Key Features

• Type 316 Stainless Steel material - provides outstanding corrosion resistance in saltwater, coastal, and chemically treated lumber environments, helping your deck fasteners last as long as the structure itself
• Annular-ring shank - the ring pattern grips surrounding wood fibers aggressively, increasing withdrawal resistance and reducing the risk of nail heads popping up over time in decking boards
• 9-gauge, 0.148" shank diameter - a larger shank cross-section penetrates both green and seasoned preservative-treated pine without pre-drilling, speeding up installation on the job site
• Full round checkered head pattern - the checker texture blends with wood grain and reduces glare from sunlight, maintaining a cleaner, more natural appearance on finished deck surfaces
• Diamond point tip - the sharp, angled point starts easily and drives straight, reducing splitting risk and making each nail faster to set
• 12d penny size, 3-1/4" length - a standard decking length that provides adequate penetration depth into joists and framing for a structurally sound connection
• 5/16" head diameter - a proportionally sized head provides solid bearing surface against decking boards without over-countersinking
• Made in the United States - manufactured domestically to consistent quality standards for use in professional and residential deck building projects

Why This Product

• Built for preservative-treated lumber compatibility - the 9-gauge annular-ring shank is specifically designed to penetrate both green and seasoned pressure-treated pine, so you can nail off freshly treated boards the same day they are delivered without fighting the nail or splitting the wood
• Right stainless grade for seaside and harsh outdoor use - Type 316 stainless steel offers a higher level of corrosion resistance than Type 304, making this nail appropriate for dock construction, beachside decks, and any application where salt spray, moisture, or chemical exposure from treated lumber would degrade a lesser fastener over time
• Withdrawal resistance that holds over time - the annular-ring shank mechanically locks into surrounding wood fibers, helping prevent the seasonal wood movement and board cupping common in outdoor decking from working nails loose and creating raised heads that become a tripping hazard
• A complete decking-specific design in one fastener - the combination of checkered head, diamond point, ring shank, and 316 stainless construction means every specification on this nail addresses a specific challenge in outdoor wood decking, rather than using a generic fastener adapted to the task

Specifications

• Brand: Simpson Strong-Tie
• Penny Size: 12d
• Length: 3-1/4 in.
• Gauge: 9
• Shank Diameter: 0.148 in.
• Head Diameter: 5/16 in.
• Shank Type: Annular-Ring Shank
• Head Type: Full Round Head
• Head Pattern: Checkered
• Point Type: Diamond Point
• Finish: Type 316 Stainless Steel
• Material: Type 316 Stainless Steel
• Approx. Count Per Lb: 60
• Country of Origin: United States

Available Pack Options

• T12PTD1: 1 Lb (60)
• T12PTD5: 5 Lb (300)
• T12PTDB: 25 Lb (1500)

Frequently Asked Questions

Why should I choose Type 316 stainless steel over Type 304 for my deck project?

Type 316 stainless steel contains additional molybdenum compared to Type 304, which significantly improves its resistance to chlorides, salt water, and the chemicals found in preservative-treated lumber. If your project is near the ocean, a lake, or involves ACQ or similar treated wood, Type 316 is the recommended grade because it resists the accelerated corrosion that would compromise a Type 304 or galvanized fastener over time.

What does an annular-ring shank do differently than a smooth shank nail?

An annular-ring shank has a series of ridges along its length that lock into the surrounding wood fibers as the nail is driven. This mechanical grip dramatically increases withdrawal resistance - meaning the nail resists being pulled back out far more than a smooth shank nail of the same size. For outdoor decking that expands and contracts seasonally, this prevents nail heads from gradually working up through the board surface over time.

Can this nail be used in both green and seasoned preservative-treated pine?

Yes. The 9-gauge, 0.148" shank diameter is specifically sized to penetrate both green (freshly treated, higher moisture content) and seasoned (dried) preservative-treated pine. The diamond point also helps start the nail cleanly in denser or wetter wood, reducing the effort required during installation without pre-drilling.

Is the checkered head pattern purely cosmetic or does it serve a function?

The checkered head pattern on this decking nail serves both a functional and aesthetic purpose. Functionally, the texture helps blend the nail head with the visual grain of the wood surface. Aesthetically, it reduces glare from direct sunlight on the metal head, resulting in a cleaner finished appearance on your deck surface compared to a smooth bright head.

Note: Product dimensions may differ from picture.