The Simpson Strong-Drive SDWS Timber Screw in 0.275" diameter by 10" length is a heavy-duty structural fastener engineered from Type 316 Stainless Steel, delivering exceptional corrosion resistance in the most demanding environments - including coastal, marine, and severe-exposure applications such as docks, piers, boardwalks, wharves, and ledger connections. Designed as a high-strength alternative to through-bolting and traditional lag screws, this washer-head timber screw simplifies structural wood-to-wood and engineered-wood connections without sacrificing load performance. Code listed under IAPMO UES ER-192 and meeting 2018 and 2021 IRC and IBC requirements, this fastener gives contractors and DIYers confidence that their structural assemblies meet recognized building standards.

Key Features

• Type 316 Stainless Steel material - provides severe corrosion resistance in saltwater, marine, and chemically aggressive environments where standard finishes would fail prematurely
• 0.275" heavy-duty shank diameter - delivers the structural shear and withdrawal strength needed to replace through-bolts and traditional lag screws in critical connections
• 10" length with 3" thread length - enables deep penetration into heavy timber members, maximizing holding power in thick structural assemblies
• SawTooth Point - cuts through wood fibers cleanly on entry, reducing splitting and eliminating the need for pre-drilling in many applications
• Washer Head with 0.650" head diameter - distributes clamping load across a wider surface area, reducing wood crushing and providing a secure, flush-bearing seat
• T50 6-Lobe drive type - offers high torque transfer with minimal cam-out, making installation faster and more reliable with the included driver bit
• 5 TPI (threads per inch) coarse thread - bites aggressively into wood fibers for strong withdrawal resistance in structural timber and engineered-wood applications
• Code listed under IAPMO UES ER-192 and meets 2018 and 2021 IRC and IBC requirements - supports permit-ready installations across a wide range of common wood framing applications

Why This Product

• A direct, code-compliant replacement for lag screws and through-bolts - the SDWS Timber screw is specifically designed to substitute traditional fastening methods, reducing installation time and hardware complexity on structural framing, ledger boards, and engineered-wood connections
• Built for the harshest corrosion environments - Type 316 Stainless Steel construction makes this screw the right choice for marine structures, coastal boardwalks, piers, and wharves where standard carbon steel or even galvanized fasteners would corrode and lose structural integrity over time
• Designed for both professional contractors and experienced DIYers - the self-starting SawTooth point, included T50 driver bit, and straightforward installation process mean fewer prep steps and faster completion without compromising structural performance
• Meets current model building code requirements - compliance with 2018 and 2021 IRC and IBC standards under IAPMO UES ER-192 means inspectors and engineers can verify this fastener's suitability for permitted structural work without extensive custom engineering

Specifications

• Brand: Simpson Strong-Tie
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Length: 10 in.
• Shank Diameter: 0.275 in.
• Head Diameter: 0.650 in.
• Head Type: Washer Head
• Drive Type: T50 6-Lobe
• Thread Length: 3 in.
• TPI: 5
• Point Type: SawTooth Point
• Code Listing: IAPMO UES ER-192; meets 2018 and 2021 IRC and IBC requirements

Available Pack Options

• SDWS271000SSRC10: 10 Pk - includes one 6-lobe, T-50 driver bit
• SDWS271000SS-R30: 30 Pk - includes one 6-lobe, T-50 driver bit

Approved Applications

• Structural wood-to-wood connections in coastal and severe corrosion environments
• Engineered-wood structural connections where code-listed fasteners are required
• Docks, piers, wharves, and marine structures subject to saltwater exposure
• Boardwalks and outdoor decking in high-humidity or coastal regions
• Ledger board connections requiring high-strength, corrosion-resistant fasteners
• Common wood framing applications meeting 2018 and 2021 IRC and IBC code requirements

Frequently Asked Questions

Can the Simpson SDWS Timber Screw replace lag screws in structural framing applications?

Yes. The Strong-Drive SDWS Timber Screw is specifically designed to provide a high-strength alternative to through-bolting and traditional lag screws. It is code listed under IAPMO UES ER-192 and meets 2018 and 2021 IRC and IBC requirements for several common wood framing and engineered-wood applications, making it a recognized, permit-ready substitution in structural connections.

Why is Type 316 Stainless Steel used instead of a coated or galvanized finish?

Type 316 Stainless Steel offers a higher level of corrosion resistance than standard coatings or hot-dip galvanizing, particularly in environments with saltwater, chlorides, or harsh chemicals. This makes the SDWS Timber Screw the appropriate choice for marine and coastal structures such as piers, wharves, boardwalks, and docks where severe corrosion exposure is a long-term concern.

Do I need to pre-drill before installing this screw?

The SawTooth Point on this screw is designed to cut through wood fibers on entry, which helps reduce splitting and can eliminate the need for pre-drilling in many structural timber and engineered-wood applications. Always follow applicable code requirements and the manufacturer's installation guidelines for your specific application.

What drive bit does this screw require, and is one included?

This screw uses a T50 6-Lobe drive, which provides high torque transfer and helps prevent cam-out during installation. A 6-lobe T-50 driver bit is physically included with the product, so you can get started without sourcing a separate bit.

Note: Product dimensions and/or thread length may differ from picture. Please see the item specifications above for exact dimensions.