Simpson 20d 4" Wood Siding Nail in Type 304 Stainless Steel by Simpson Strong-Tie is engineered for reliable, long-lasting fastening of wood siding panels in exterior applications. Featuring an annular-ring shank for superior withdrawal resistance and a checker-patterned full round head that blends naturally with wood grain, this 10-gauge nail delivers the holding power and pull-through resistance that exterior siding projects demand. Whether you are installing wood siding on a new build or re-cladding an existing structure, this corrosion-resistant fastener is built to perform in demanding outdoor environments.

Key Features

• Type 304 Stainless Steel material - provides strong corrosion resistance for exterior and outdoor siding applications, helping fasteners maintain integrity over years of weather exposure
• Annular-ring shank - increases withdrawal resistance so the nail grips wood fibers tightly, reducing cupping of siding boards and keeping panels securely in place
• Checkered full round head pattern - blends with wood grain, reduces glare from sunlight, and accepts surface finishes for a cleaner finished appearance
• Diamond point tip - allows for easier driving into wood siding material, reducing installation effort and minimizing splitting
• 10-gauge, 4" length (20d penny size) - sized specifically for fastening wood siding panels with excellent pull-through resistance and deep, secure penetration
• 1/4" head diameter - provides a broad bearing surface for pull-through resistance without over-countersinking into siding panels
• Made in the United States - manufactured to Simpson Strong-Tie's quality standards, ensuring consistent dimensions and performance across every nail

Why This Product

• Engineered specifically for wood siding - the combination of an annular-ring shank and checkered head pattern is purpose-built to secure siding panels with exceptional holding power, reducing the risk of board movement, cupping, or pull-through over time
• Type 304 Stainless Steel construction resists corrosion - making this nail a dependable choice for exterior siding exposed to rain, humidity, and temperature cycling where standard fasteners may fail prematurely
• Head design works with your finish - the checker-patterned head accepts surface finishes and blends with wood grain, resulting in a cleaner, more professional look on exposed wood siding installations
• Trusted Simpson Strong-Tie fastener - Simpson's exterior nail line is designed to meet the demands of real-world exterior construction, giving installers confidence in both corrosion resistance and structural holding performance

Specifications

• Brand: Simpson Strong-Tie
• Material: Type 304 Stainless Steel
• Finish: Type 304 Stainless Steel
• Penny Size: 20d
• Length (in.): 4
• Gauge: 10
• Shank Diameter (in.): 0.131
• Shank Type: Annular-Ring Shank
• Head Type: Full Round Head
• Head Diameter (in.): 1/4
• Head Pattern: Checkered
• Point Type: Diamond Point
• Approx. Count per Lb: 74
• Country of Origin: United States

Available Pack Options

• S20SND1: 1 Lb (74)
• S20SND5: 5 Lb (370)
• S20SNDB: 25 Lb (1850)

Approved Applications

• Fastening Wood Siding

Frequently Asked Questions

What makes the annular-ring shank better than a smooth shank for wood siding?

The annular-ring shank has rings along the shank that grip wood fibers as the nail is driven, significantly increasing withdrawal resistance compared to a smooth shank. For wood siding installations, this means panels are held more securely over time and are less likely to cup, loosen, or pull free under seasonal wood movement and weather exposure.

Is Type 304 Stainless Steel suitable for all exterior siding environments?

Type 304 Stainless Steel provides strong corrosion resistance suitable for most exterior and outdoor siding applications exposed to rain, humidity, and temperature changes. For seaside or coastal environments with heavy salt air exposure, Type 316 Stainless Steel is recommended for superior corrosion resistance in those more demanding conditions.

Why does the head have a checkered pattern?

The checker pattern on the full round head is designed to blend with natural wood grain and reduce glare from sunlight, making the nail head less visually prominent on finished wood siding. The textured surface also accepts surface finishes such as paint or stain, helping the fastener blend into the finished appearance of the siding installation.

How many of these nails are in a pound?

There are approximately 74 nails per pound. This count can help you estimate material quantities needed for your wood siding project based on the total weight you purchase.