Simpson Strong-Drive SDWH Timber-Hex Hot-Dip Galvanized Screw - 0.276 in. x 8 in. is a heavy-duty structural fastener engineered by Simpson for demanding marine, coastal, and timber construction environments. With a Hot-Dip Galvanized Class C coating, this screw delivers serious corrosion resistance in saltwater-exposed conditions such as structural pilings, piers, docks, and boardwalks - applications where moisture and salt air rapidly degrade standard fasteners. The 0.276 in. shank diameter and 8 in. length provide deep, secure penetration into heavy timber, while the SawTooth point and serrated threads allow installation from a single side without predrilling, dramatically cutting labor time and total installed cost on pile and dock projects.

Key Features

• Hot-Dip Galvanized Class C coating - provides robust corrosion resistance suited to marine, coastal, and wet outdoor environments where standard zinc coatings fall short
• SawTooth point - cuts through heavy timber without predrilling, reducing labor steps and eliminating the need for expensive auger drill bits on the job site
• Serrated threads with 5 TPI - aggressive thread profile bites firmly into structural wood and engineered lumber, maximizing holding strength in pile and dock connections
• Large Hex Washer Head (0.930 in. diameter) with 3/8 in. hex drive - the oversized integral washer distributes clamping load across the wood surface, replacing the need for separate washers, nuts, or bolts in comparable applications
• 3 in. thread length - concentrated threaded engagement zone optimized for structural timber-to-timber connections and pile fastening
• Single-sided installation - one person can complete the fastening operation from one side of the connection, reducing crew requirements and speeding up dock, pier, and boardwalk construction
• No predrilling required - saves time and eliminates the cost of specialized drill bits, lowering the overall installed cost compared to traditional bolt-washer-nut assemblies

Why This Product

• Designed specifically for structural piling, pier, dock, and boardwalk applications - this fastener addresses the real-world challenges of marine timber construction where corrosion, access limitations, and installation speed all matter
• Eliminates the multi-component hardware stack of traditional 3/4 in. or 5/8 in. HDG bolt-washer-nut assemblies - no separate washers, nuts, or bolts to source, handle, or install, which reduces material cost and simplifies the supply chain for coastal projects
• Hot-Dip Galvanized Class C finish means this screw is built to hold up in the harshest saltwater and high-humidity coastal environments where fastener longevity directly affects structural safety and maintenance intervals
• One-sided installation with no predrilling makes this fastener practical for tight or hard-to-access timber connections on piers and docks, cutting total installation time and labor cost compared to traditional bolted pile solutions

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter (in.): 0.276
• Length (in.): 8
• Coating: Hot-Dip Galvanized, Class C
• Head Type: Large Hex Washer Head
• Head Diameter (in.): 0.930
• Drive Type: 3/8 in. Hex
• Thread Type: Serrated Threads
• Thread Length (in.): 3
• TPI: 5
• Point Type: SawTooth Point
• Country of Origin: Taiwan

Available Pack Options

• SDWH27800G-RP1: 1 Ea
• SDWH27800GR30: 30 Pk - includes (1) driver bit
• SDWH27800GMB: 150 Pk - includes (2) driver bits

Approved Applications

• Structural pilings, piers, docks, and boardwalks in marine and coastal environments
• Structural wood-to-wood connections in heavy timber construction
• Engineered wood connections including ledgers and pile connections
• Replacement for HDG bolt-washer-nut assemblies in comparable pile fastening conditions

Install With

• For best results, use a minimum of 1/2 in. low-speed corded drill to install

Frequently Asked Questions

Does this screw require predrilling before installation?

No predrilling is required. The SawTooth point is designed to self-start in structural timber, allowing you to drive the screw directly without an auger drill bit or pilot hole - saving time and eliminating the cost of specialized tooling on pile and dock jobs.

What type of drive tool is needed to install this screw?

The screw uses a 3/8 in. hex drive. For best results, use a minimum of 1/2 in. low-speed corded drill to install. The large hex washer head provides a solid drive interface for high-torque applications in heavy structural timber.

Is this screw suitable for saltwater and coastal environments?

Yes. The Hot-Dip Galvanized Class C coating is specifically suited for heavy-duty marine and coastal applications including structural pilings, piers, docks, and boardwalks where exposure to saltwater and high humidity demands a more durable corrosion-resistant finish than standard coatings provide.

Can this screw replace traditional bolt-washer-nut assemblies in pile connections?

Yes. The large integral hex washer head (0.930 in. diameter) eliminates the need for separate washers, nuts, or bolts. Two of these screws can replace a single 3/4 in. or 5/8 in. HDG bolt-washer-nut assembly in many pile connection conditions, reducing hardware costs and simplifying installation.