The Simpson Strong-Drive DWP Wood Screw in #12 x 4-1/2" with a Flat Head is a load-rated structural fastener engineered for demanding exterior applications including decks, docks, boardwalks, and anywhere prolonged exposure to moisture or severe corrosion is a concern. Built from Type 305 Stainless Steel, this heavy-duty wood screw delivers the corrosion resistance needed for structural connections near water while meeting ICC-ES acceptance criteria AC233 for verified load performance in shear, pull-through, and withdrawal resistance. Whether you're fastening composite decking, engineered lumber, or solid wood framing in high-moisture environments, this screw provides the confidence of tested, rated performance from Simpson.

Key Features

• Type 305 Stainless Steel construction - provides superior corrosion resistance for exterior structural connections exposed to moisture, humidity, and harsh outdoor conditions
• Unique box thread design with raised-ridge technology - greatly reduces driving torque so you can drive more screws per battery charge, improving productivity on large deck and dock projects
• Specially designed sharp point - penetrates hardwood and dense wood products with ease, eliminating the need for pre-drilling in many applications
• T27 6-Lobe drive - provides a secure, precise bit fit that reduces cam-out, making each drive smoother and extending bit life significantly
• Flat head profile - sits flush with the surface for a clean, professional finish on deck boards and other exposed wood surfaces
• ICC-ES AC233 tested and load rated - verified for shear, pull-through, and withdrawal resistance, meeting structural fastener requirements for engineered exterior connections
• Compatible with wood, engineered wood, and polymer materials - offers versatility across a wide range of decking and framing substrates common in dock and boardwalk construction

Why This Product

• Structural rating you can document - tested to ICC-ES acceptance criteria AC233, this screw carries load ratings for shear, pull-through, and withdrawal, making it appropriate for use where engineered connection specs must be met or verified by an inspector
• Built for high-corrosion and near-water environments - Type 305 Stainless Steel construction makes this fastener the right choice for docks, waterfront boardwalks, and coastal decks where standard coated screws would fail prematurely
• Reduced fatigue on large jobs - the box thread design lowers driving torque, meaning less strain on cordless tools and less wear on the installer during high-volume fastening on deck or dock projects
• Engineered for exterior structural connections - the combination of sharp-point tip, box threads, and 4-1/2" length makes this screw well-suited for thick exterior assemblies where holding strength and penetration depth are critical

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #12
• Length: 4-1/2 in.
• Head Type: Flat Head
• Head Diameter: 0.435 in.
• Drive Type: T27 6-Lobe
• Thread Type: Box Threads
• Point Type: Sharp Point
• Material: Type 305 Stainless Steel
• Finish: Type 305 Stainless Steel
• Approx. Count Per Lb.: 32
• Country of Origin: Taiwan

Available Pack Options

• S12450WP1: 1 Lb (32) - includes (1) T27 6-lobe driver bit
• S12450WP5: 5 Lb (160) - includes (1) T27 6-lobe driver bit
• S12450WPB: 750 Pk - includes (2) T27 6-lobe driver bits

Approved Applications

• Deck construction and decking board fastening in exterior environments
• Dock and waterfront structural connections exposed to water or high moisture
• Boardwalk framing and surface fastening near bodies of water
• General exterior structural applications requiring corrosion-resistant, load-rated fasteners
• Connections using wood, engineered wood, and polymer materials in high or severe corrosion exposure zones

Frequently Asked Questions

What makes the DWP Wood SS screw suitable for structural applications?

This screw has been tested in accordance with ICC-ES acceptance criteria AC233 and carries verified load ratings for shear, pull-through, and withdrawal resistance. This makes it appropriate for use in engineered exterior structural connections where performance documentation is required.

Why is Type 305 Stainless Steel recommended for dock and deck applications?

Type 305 Stainless Steel provides a high level of corrosion resistance, making it well-suited for exterior applications exposed to moisture, humidity, and severe corrosion conditions such as docks, boardwalks, and waterfront decks. For seaside or saltwater-adjacent applications, Simpson recommends considering Type 316 stainless steel for even greater protection.

What is the advantage of the box thread design on this screw?

The unique box thread design incorporates raised-ridge technology that greatly reduces the driving torque required. This means less strain on cordless tools during high-volume fastening, allowing you to drive more screws on a single battery charge - a meaningful advantage on large deck or dock installations.

Does the sharp point eliminate the need for pre-drilling?

The specially designed sharp point on this screw is engineered to penetrate hard wood products and dense materials with ease. This reduces or eliminates the need for pre-drilling in many common exterior wood and engineered wood applications, saving time and steps during installation.

Note: Product dimensions may differ from picture.