Simpson 20d x 4" Preservative-Treated Wood Decking Nail in Type 304 Stainless Steel by Simpson Strong-Tie is engineered for exterior deck and dock construction where long-term corrosion resistance and holding power are essential. Featuring an annular-ring shank and a full round checkered head, this fastener drives cleanly into both green and seasoned preservative-treated pine while delivering superior withdrawal resistance that keeps nail heads flush over the life of your decking project. Made in the United States, it is a trusted choice for builders and contractors who demand reliable performance in outdoor structural applications.

Key Features

• Type 304 Stainless Steel material - provides strong corrosion resistance for exterior and pressure-treated lumber applications, helping your deck or dock stand up to moisture and the elements over time
• Annular-ring shank - increases withdrawal resistance compared to smooth-shank nails, reducing nail-head pop-up and keeping your decking surface flat and secure for years
• Larger 8-gauge / 0.162" shank diameter - penetrates both green and seasoned preservative-treated pine with ease, minimizing splitting and simplifying installation
• Full round checkered head pattern - the textured surface blends with natural wood grain and reduces glare from sunlight, giving your finished deck a cleaner, more professional look
• Diamond point tip - promotes easier driving and more accurate nail placement, reducing installer effort on demanding exterior projects
• 20d penny size at 4" length - sized appropriately for standard deck board fastening, providing the depth of penetration needed for a secure, lasting connection
• Made in the United States - manufactured to consistent quality standards for use in professional and residential deck and dock construction

Why This Product

• Designed specifically for preservative-treated wood decking and dock projects, this nail addresses the unique challenges of exterior fastening - resisting the chemical reactions that can cause standard nails to corrode and stain treated lumber over time
• The annular-ring shank directly combats one of the most common deck maintenance problems - nail heads rising above the surface - by dramatically increasing withdrawal resistance compared to smooth-shank alternatives
• The 8-gauge diameter strikes a practical balance for treated pine: large enough to create a strong connection, yet designed to drive cleanly without excessive splitting in both green and dried lumber
• For projects in moderate outdoor environments, Type 304 stainless steel delivers reliable corrosion resistance; builders working near coastal or saltwater conditions should consider Type 316 stainless steel for a higher level of protection

Specifications

• Brand: Simpson Strong-Tie
• Material / Finish: Type 304 Stainless Steel
• Penny Size: 20d
• Length: 4 in.
• Gauge: 8
• Shank Diameter: 0.162 in.
• Shank Type: Annular-Ring Shank
• Head Type: Full Round Head
• Head Diameter: 11/32 in.
• Head Pattern: Checkered
• Point Type: Diamond Point
• Approx. Count Per Lb: 40
• Country of Origin: United States

Available Pack Options

• S20PTD1: 1 Lb (40)
• S20PTD5: 5 Lb (200)
• S20PTDB: 25 Lb (1000)

Approved Applications

• Deck board fastening in residential and commercial outdoor deck construction
• Dock construction and waterfront structure projects
• Fastening into green preservative-treated pine lumber
• Fastening into seasoned (dried) preservative-treated pine lumber
• Exterior structural connections requiring corrosion-resistant fasteners

Frequently Asked Questions

What type of lumber is this nail designed for?

This decking nail is designed specifically for use with preservative-treated pine lumber. Its larger shank diameter allows for easy installation into both green (freshly treated) and seasoned (dried) preservative-treated wood, making it versatile across different stages of deck and dock construction.

Why does the annular-ring shank matter for deck projects?

The annular-ring shank provides increased withdrawal resistance compared to a smooth shank. In decking applications where boards expand and contract with seasonal moisture changes, this added holding power helps prevent nail heads from rising above the surface over time - a common maintenance issue with lesser fasteners.

What is the difference between Type 304 and Type 316 stainless steel for this application?

Type 304 stainless steel offers reliable corrosion resistance for most outdoor and preservative-treated lumber environments. Type 316 stainless steel provides a higher level of corrosion resistance and is recommended for seaside or coastal applications where salt air and saltwater exposure are ongoing concerns. If your project is near the ocean or in a high-salt environment, Type 316 is the stronger choice.

What does the checkered head pattern on this nail do?

The checkered head pattern serves two practical purposes: it visually blends with the natural grain texture of wood decking for a cleaner finished appearance, and it reduces glare from sunlight reflecting off a smooth nail head - a detail that improves the overall look of an installed deck surface.

Note: Product dimensions may differ from picture.