Simpson Strong-Drive SDWS Timber Screw in Type 316 Stainless Steel - 0.275" x 8" is a heavy-duty structural fastener engineered to deliver a high-strength, code-compliant alternative to through-bolting and traditional lag screws. Built from severe-corrosion-resistant Type 316 Stainless Steel, this 8-inch structural screw is purpose-built for coastal and harsh outdoor environments where saltwater exposure, chemical contact, and moisture can degrade standard fasteners over time. The washer head design and SawTooth point work together to simplify installation - no pre-drilling required in many applications - making it a practical choice for both professional contractors and do-it-yourself builders tackling docks, piers, boardwalks, wharves, ledgers, and structural wood framing connections.

Key Features

• Type 316 Stainless Steel material - provides severe-corrosion resistance that outlasts standard stainless steel in saltwater, marine, and chemically aggressive environments, keeping structural connections intact over the long term
• 0.275" heavy-duty shank diameter - delivers the load-bearing capacity needed for structural wood-to-wood and engineered-wood connections, reducing reliance on traditional lag screws or through-bolts
• 8" length with 3" thread length - achieves deep penetration into structural members for strong, lasting engagement in thick timber and engineered-wood assemblies
• SawTooth point - cuts through wood fibers cleanly to reduce splitting and minimize the need for pre-drilling, saving time during installation
• Washer head with 0.650" head diameter - distributes clamping load over a wider surface area, improving pull-through resistance and surface bearing performance
• T50 6-Lobe drive type - provides high torque transfer with reduced cam-out risk, allowing the screw to be driven fully without stripping, even in dense timber
• 5 TPI (threads per inch) coarse thread - optimized for structural wood and timber applications, maximizing withdrawal resistance in solid and engineered wood members
• Code listed under IAPMO UES ER-192 - meets 2018 and 2021 IRC and IBC requirements for common wood framing and engineered-wood applications, so specifiers and inspectors have the documentation they need

Why This Product

• Where standard lag screws or through-bolts are the traditional solution, this SDWS Timber screw offers a faster, equally strong installation with no through-hole drilling required on many assemblies - reducing labor time and hardware complexity on structural connections.
• For projects in coastal zones, marine environments, or anywhere severe corrosion is a concern - docks, wharves, piers, and boardwalks - the Type 316 Stainless Steel construction provides a level of corrosion resistance specifically suited to those demanding conditions.
• The combination of IRC and IBC code compliance under IAPMO UES ER-192 means this fastener can be specified and used with confidence on permitted construction projects, satisfying inspector requirements for structural wood framing and engineered-wood connections.
• The SawTooth point and T50 6-Lobe drive make this screw accessible to contractors and do-it-yourselfers alike - clean entry, strong drive, and straightforward installation without specialized tools beyond a standard T50 bit.

Specifications

• Brand: Simpson Strong-Tie
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Length (in.): 8
• Shank Diameter (in.): 0.275
• Head Diameter (in.): 0.650
• Head Type: Washer Head
• Drive Type: T50 6-Lobe
• Point Type: SawTooth Point
• Thread Length (in.): 3
• TPI: 5

Available Pack Options

• SDWS27800SS-RC10: 10 Pk - includes one 6-lobe, T-50 driver bit
• SDWS27800SS-R30: 30 Pk - includes one 6-lobe, T-50 driver bit
• SDWS27800SS: 200 Pk - includes two 6-lobe, T-50 driver bits

Approved Applications

• Structural wood-to-wood connections in coastal or severe corrosion environments
• Engineered-wood connections requiring code-listed structural fasteners
• Docks, wharves, piers, and boardwalks where saltwater and moisture exposure is continuous
• Ledger connections on decks and marine structures
• Common wood framing applications meeting 2018 and 2021 IRC and IBC code requirements

Frequently Asked Questions

Does this screw require pre-drilling before installation?

The SawTooth point is designed to cut through wood fibers as the screw is driven, which reduces the likelihood of wood splitting and can eliminate the need for pre-drilling in many structural timber applications. Always follow the project's engineering requirements and applicable code guidelines for final confirmation.

What code approvals does the Simpson SDWS Timber Stainless Steel screw carry?

This screw is code listed under IAPMO UES ER-192 and meets the requirements of the 2018 and 2021 International Residential Code (IRC) and International Building Code (IBC) for several common wood framing and engineered-wood applications, making it suitable for use on permitted construction projects.

Why is Type 316 Stainless Steel specified instead of standard stainless steel for marine and coastal applications?

Type 316 Stainless Steel contains molybdenum, which provides significantly enhanced resistance to chloride corrosion compared to Type 304 stainless steel. This makes it the appropriate material choice for piers, docks, boardwalks, wharves, and ledgers exposed to saltwater, salt air, and other chemically aggressive environments where long-term structural integrity is critical.

What size driver bit is needed to install this screw?

This screw uses a T50 6-Lobe drive, so a T50 Torx-compatible bit is required for installation. The 6-lobe geometry provides high torque transfer and reduces cam-out risk when driving the screw fully into dense timber or engineered-wood members.

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