The Simpson Strong-Drive DWP Wood Screw in #12 x 4-1/2", Type 316 Stainless Steel with Flat Head is a structural fastening solution built for demanding exterior environments where corrosion resistance and verified load performance are non-negotiable. Engineered by Simpson for deck, dock, boardwalk, and general exterior construction near water or in high-corrosion conditions, this flat-head wood screw delivers the holding strength and material integrity that structural connections require. The Type 316 stainless steel composition goes beyond standard corrosion protection - it withstands saltwater exposure, harsh coastal conditions, and severe chemical environments, making it the right choice for seaside installations and wet outdoor structures.

Key Features

• Type 316 Stainless Steel material - provides superior resistance to saltwater, moisture, and severe corrosion, making this fastener well-suited for docks, boardwalks, and coastal deck applications where standard finishes would fail prematurely.
• Unique box thread design with raised-ridge technology - significantly reduces driving torque so installers can drive more screws per battery charge, increasing jobsite efficiency and reducing tool fatigue.
• Specially designed sharp point - penetrates hardwood and dense wood products with ease, eliminating the need for pre-drilling in many applications and speeding up installation.
• T27 6-Lobe drive - creates a secure bit-to-screw fit that minimizes cam-out, delivers a smooth and consistent drive, and extends bit life compared to standard drive types.
• Flat head profile - sits flush with or below the surface of the material, providing a clean finished appearance on decks and structural wood assemblies.
• Tested to ICC-ES acceptance criteria AC233 - this screw is load rated for shear, pull-through, and withdrawal resistance, so engineers and inspectors have verified performance data to reference on code-sensitive projects.
• Compatible with wood, engineered wood, and polymer materials - offers versatility across a wide range of exterior structural applications without requiring a separate fastener for each substrate.

Why This Product

• Verified structural ratings for code-sensitive work - load ratings for shear, pull-through, and withdrawal resistance tested under ICC-ES AC233 mean this fastener can be specified on permitted decks, docks, and boardwalks where documentation of fastener performance is required.
• Type 316 stainless steel for the most corrosive environments - when a project is directly exposed to saltwater, tidal splash, or high-humidity coastal air, Type 316 stainless steel offers a meaningful step up in corrosion resistance over standard stainless or coated carbon steel fasteners.
• Box thread and sharp point combination reduces driving effort - the pairing of raised-ridge box threads with a sharp penetrating point means less resistance during installation, which preserves both battery charge and installer stamina across large decking projects.
• Flat head design integrates cleanly into exterior decking surfaces - the 0.435" head diameter sits flush, keeping walking surfaces smooth and preventing trip hazards on deck and boardwalk installations.

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 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Approx. Count Per Lb.: 32
• Country of Origin: Taiwan

Available Pack Options

• T12450WP1: 1 Lb (32) - includes (1) T27 6-lobe driver bit
• T12450WP5: 5 Lb (160) - includes (1) T27 6-lobe driver bit
• T12450WPB: 750 Pk - includes (2) T27 6-lobe driver bits

Frequently Asked Questions

What makes Type 316 stainless steel different from other stainless steel grades for outdoor fasteners?

Type 316 stainless steel contains molybdenum, which provides enhanced resistance to chlorides and saltwater compared to standard 304 stainless. This makes it particularly appropriate for seaside installations such as docks, boardwalks, and decks directly exposed to ocean air or salt spray, as noted in the product specifications for this fastener.

Is this screw load rated for structural connections, or is it only suitable for general fastening?

This screw is a structural fastener that has been tested in accordance with ICC-ES acceptance criteria AC233 and is load rated for shear, pull-through, and withdrawal resistance. It is appropriate for exterior engineered structural connections including decks, docks, and boardwalks where verified load performance is required.

What drive bit does this screw require?

This screw uses a T27 6-Lobe drive. The 6-lobe design provides a secure bit fit that reduces cam-out during driving and extends bit life, making it important to use the correct T27 bit for best results.

Can this screw be used with engineered wood or polymer decking materials, or only solid lumber?

According to the product data, this Strong-Drive DWP Wood SS screw is compatible with wood, engineered wood, and polymer materials, making it a versatile choice for a variety of exterior structural and decking applications.

Note: Product dimensions may differ from picture.