The Simpson Strong-Drive SDWS Timber Screw with Double-Barrier Coating is a high-strength structural fastener engineered as a direct, code-compliant alternative to through-bolts and traditional lag screws in wood framing and timber construction. Featuring a 0.220-inch shank diameter, 5-inch length, and a black Double-Barrier Coating finish, this screw delivers reliable corrosion resistance comparable to hot-dip galvanization - making it well suited for both interior framing and select exterior or preservative-treated wood applications. Whether you are a professional contractor or a confident do-it-yourselfer, this timber screw is designed for fast, clean installation with no predrilling required in most applications.

Key Features

• Double-Barrier Coating - provides corrosion resistance equivalent to hot-dip galvanization, making this screw suitable for certain exterior environments and preservative-treated lumber where ordinary fasteners would degrade
• SawTooth Point - cuts into wood fibers quickly for fast, self-starting penetration, reduces installation torque, and eliminates the need for predrilling in most wood framing applications
• T40 6-Lobe Drive - delivers positive bit engagement that reduces cam-out, makes driving easier, and extends driver bit life during extended installations
• Washer Head with 0.760-inch head diameter - creates a large bearing surface against the wood, spreading load and reducing the risk of pull-through in structural connections
• Underhead nibs - allow the head to countersink flush with the wood surface while minimizing surface splintering for a cleaner, more professional finish
• Bold thread design with 5 TPI and 3-inch thread length - maximizes grip and holding power in the receiving member for a high-strength wood-to-wood connection
• Code listed in IAPMO UES ER-192 - meets IRC and IBC code requirements for most common wood framing applications, giving contractors and inspectors confidence on the job site
• Size identification on screw head - allows quick visual confirmation of the correct fastener on site, reducing installation errors

Why This Product

• Replaces through-bolts and lag screws without predrilling - the SawTooth point and engineered thread profile allow this screw to be driven directly in most wood framing situations, saving time and labor compared to traditional through-bolting methods
• Corrosion performance matched to hot-dip galvanization - the Double-Barrier Coating makes this screw a practical choice for pressure-treated lumber and certain outdoor structural applications where long-term fastener integrity is critical
• Engineered for structural confidence - IAPMO UES ER-192 code listing and compliance with IRC and IBC requirements means this screw is accepted for most common wood framing applications, reducing approval uncertainty on permitted projects
• Versatile fit for wood-to-wood fastening and crating - the 5-inch length and 0.220-inch shank are well matched for connecting dimensional lumber and timber members where a strong, durable mechanical connection is needed

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter: 0.220 in.
• Length: 5 in.
• Head Diameter: 0.760 in.
• Head Type: Washer Head
• Drive Type: T40 6-Lobe
• Point Type: SawTooth Point
• Thread Length: 3 in.
• TPI: 5
• Coating: Double-Barrier Coating
• Finish: Double-Barrier Coating
• Color: Black

Available Pack Options

• SDWS22500DBB-R50: 50 Pk - includes one 6-lobe, T40 driver bit
• SDWS22500DBBMB: 250 Pk - includes one 6-lobe, T40 driver bit
• SDWS22500DBB: 600 Pk - includes two 6-lobe, T40 driver bits

Approved Applications

• Fastening Wood-to-Wood
• Crating

Install With

• SDWS screws install best with a low-speed 1/2-in. drill and 6-lobe, T40 driver bit (included)

Frequently Asked Questions

Do I need to predrill before installing this timber screw?

In most applications, predrilling is not required. The SawTooth point is specifically designed to cut into wood fibers quickly, reduce installation torque, and allow the screw to self-start - eliminating the predrilling step for most standard wood framing and crating work.

Is this screw suitable for use with pressure-treated lumber?

Yes, for certain applications. The Double-Barrier Coating provides corrosion resistance equivalent to hot-dip galvanization, which makes it suitable for use in certain exterior and preservative-treated wood applications as described in the IAPMO UES ER-192 evaluation report. Always verify your specific application against that report.

What drive tool is recommended for installing these screws?

These screws install best with a low-speed 1/2-in. drill paired with a 6-lobe T40 driver bit. The T40 6-lobe drive system is designed to provide positive engagement, reduce cam-out, and extend driver bit service life.

Are these screws code compliant for structural wood framing?

Yes. The Strong-Drive SDWS Timber Screw is code listed in IAPMO UES ER-192 and meets IRC and IBC code requirements for most common wood framing applications, making it an accepted alternative to through-bolts and traditional lag screws on permitted construction projects.