The Simpson Strong-Drive SDWS TIMBER 0.275" x 4" Stainless Steel Screw is a heavy-duty structural fastener engineered for high-strength wood connections in the most demanding environments. Built from Type 316 stainless steel, this screw delivers severe corrosion resistance that stands up to saltwater, marine exposure, and harsh coastal conditions - making it the go-to choice for docks, wharves, piers, boardwalks, and ledger connections where long-term structural integrity is non-negotiable. Designed as a practical alternative to through-bolting and traditional lag screws, it installs faster and with less labor while meeting the strength requirements contractors and DIYers need for code-compliant structural framing.

Key Features

• Type 316 Stainless Steel material - provides severe corrosion resistance for use in saltwater, coastal, and chemically aggressive environments where standard steel fasteners would fail prematurely
• 0.275" heavy-duty shank diameter - delivers high shear and withdrawal strength comparable to through-bolts and lag screws, without the added complexity of drilling clearance holes
• SawTooth point - bites into wood fibers aggressively and self-starts without pre-drilling, saving installation time on structural wood and engineered-wood applications
• Washer head with 0.650" head diameter - distributes clamping load over a wide bearing surface, reducing the risk of wood crushing and creating a strong, secure connection
• T50 6-Lobe drive type - resists cam-out under high torque, giving installers greater control and reducing tool slippage during driving
• 5 TPI thread with 3" thread length - designed for maximum pull-out resistance in structural lumber and engineered-wood members
• Code listed under IAPMO UES ER-192 - meets 2018 and 2021 IRC and IBC code requirements, allowing use on permitted projects and engineered designs without additional justification

Why This Product

• A simpler replacement for lag screws and through-bolts - the SDWS TIMBER is engineered to deliver equivalent structural performance to traditional heavy hardware while eliminating the need for multiple drill bits, clearance holes, and bolt hardware, cutting installation time on jobsites
• Purpose-built for marine and severe corrosion environments - Type 316 stainless steel is specifically selected for its resistance to chloride-rich environments such as coastal boardwalks, piers, wharves, and waterfront ledgers where standard fasteners corrode rapidly
• Confidence on permitted and inspected projects - IAPMO UES ER-192 code listing and compliance with 2018 and 2021 IRC and IBC means this fastener can be called out on structural drawings and will satisfy inspectors on common wood framing and engineered-wood applications
• Suitable for both professional contractors and DIY builders - the self-starting SawTooth point, cam-out-resistant T50 6-Lobe drive, and straightforward installation make this screw accessible on projects ranging from professional dock construction to residential deck ledger connections

Specifications

• Brand: Simpson Strong-Tie
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Length: 4 in.
• Shank Diameter: 0.275 in.
• Head Diameter: 0.650 in.
• Head Type: Washer Head
• Drive Type: T50 6-Lobe
• Point Type: SawTooth Point
• Thread Length: 3 in.
• TPI: 5
• Code Listing: IAPMO UES ER-192; meets 2018 and 2021 IRC and IBC requirements

Available Pack Options

• SDWS27400SS-RC10: 10 Pk - includes one 6-lobe, T-50 driver bit
• SDWS27400SS-R30: 30 Pk - includes one 6-lobe, T-50 driver bit
• SDWS27400SS: 350 Pk - includes two 6-lobe, T-50 driver bits

Approved Applications

• Structural wood-to-wood connections in coastal and severe corrosion environments
• Engineered-wood structural connections
• Docks, wharves, piers, and boardwalks
• Ledger connections in marine and outdoor settings
• Common wood framing applications requiring IRC and IBC code compliance

Frequently Asked Questions

What makes Type 316 stainless steel appropriate for outdoor and marine structural fasteners?

Type 316 stainless steel contains molybdenum, which significantly improves resistance to chlorides and other corrosive agents compared to standard stainless grades. This makes the SDWS TIMBER 316 SS screw well-suited for structural connections at piers, boardwalks, wharves, coastal ledgers, and other settings where exposure to saltwater or high moisture is a concern.

Does this screw require pre-drilling before installation?

No. The SawTooth point is designed to self-start and penetrate wood without the need for a pilot hole in most structural applications, simplifying the installation process and reducing the number of steps required on the job.

Is this screw code compliant for structural framing projects?

Yes. The Strong-Drive SDWS TIMBER screw is code listed under IAPMO UES ER-192 and meets the requirements of the 2018 and 2021 IRC (International Residential Code) and IBC (International Building Code) for several common wood framing and engineered-wood applications.

What drive tool is needed to install this screw?

This screw requires a T50 6-Lobe (Torx-style) driver bit. The 6-Lobe interface is designed to resist cam-out under the high torque needed to drive a 0.275"-diameter structural screw, helping maintain control throughout installation.

Note: Product dimensions and/or thread length may differ from picture. Please refer to the specifications listed above for accurate product details.