The Simpson Strong-Drive SDWH Timber-Hex Hot-Dip Galvanized Screw is a heavy-duty 0.276 in. diameter x 15 in. structural fastener engineered for demanding marine, coastal, and waterfront construction environments. Built with a Hot-Dip Galvanized, Class C coating, this screw delivers reliable corrosion resistance in saltwater-exposed settings such as structural pilings, piers, docks, and boardwalks - where long-term durability and moisture resistance are critical. The large hex washer head and SawTooth point allow for single-sided installation without predrilling, dramatically reducing labor time and installation cost compared to traditional bolt and nut assemblies.

Key Features

• Hot-Dip Galvanized, Class C coating - provides heavy-duty corrosion protection suited for marine, coastal, and saltwater-exposed applications where standard coatings would fail prematurely
• 0.276 in. shank diameter x 15 in. length - delivers deep, high-strength engagement in thick structural timber and pile connections
• SawTooth Point - self-piercing tip allows installation without predrilling, saving time and eliminating the need for specialized auger drill bits
• Large Hex Washer Head with 3/8 in. hex drive - the 0.930 in. head diameter spreads load across the surface and eliminates the need for a separate washer, reducing component count and installation steps
• Serrated threads with 5 TPI and 3 in. thread length - aggressive thread geometry locks into heavy timber for strong, vibration-resistant connections in structural wood-to-wood and pile applications
• Single-sided installation - no need to access both sides of a connection, making it practical for pile and pier work where the back face is inaccessible
• No predrilling required - the SawTooth point self-starts in heavy timber, cutting total installation time and reducing the tools needed on the job site

Why This Product

• Replaces expensive bolt, washer, and nut assemblies in pile and dock construction - because no separate hardware is required, installed cost is lower than comparable 3/4 in. or 5/8 in. HDG bolt solutions
• Designed specifically for saltwater and coastal environments - the Hot-Dip Galvanized, Class C finish meets the demands of marine-grade structural applications including docks, boardwalks, and waterfront piers
• Faster job completion through single-sided access - installers work from one face only with no predrilling, reducing both labor hours and the number of tools required on site
• Eliminates the need for auger drill bits, washers, and nuts - every component needed for a complete connection is built into one fastener, simplifying procurement and reducing job site clutter

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter (in.): 0.276
• Length (in.): 15
• 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

• SDWH271500G-RP1: 1 Ea
• SDWH271500GMB: 100 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 framing
• Engineered wood connections including ledger attachments
• Pile connections requiring a single-sided fastening solution

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 allows the screw to self-pierce directly into heavy timber, eliminating the need for auger drill bits and speeding up installation.

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

This screw uses a 3/8 in. hex drive. For best results, use a minimum of a 1/2 in. low-speed corded drill to ensure adequate torque for driving a 15 in. screw into structural timber.

Why is the Hot-Dip Galvanized, Class C coating important for dock and pier applications?

Hot-Dip Galvanized, Class C is a heavy-grade zinc coating that provides significantly greater corrosion resistance than standard coatings. This makes the screw suitable for saltwater, marine, and coastal environments where exposure to moisture and salt would quickly degrade lighter-coated fasteners.

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

Yes. The SDWH Timber-Hex HDG screw is designed to replace HDG bolt, washer, and nut assemblies in many pile connection applications. Because it installs from one side only and requires no separate hardware, it reduces both material costs and installation time compared to through-bolt solutions.