The Simpson Strong-Drive SDWS Timber Screw with Double-Barrier Coating is a heavy-duty structural fastener engineered to deliver a high-strength, code-compliant alternative to traditional lag screws and through-bolting in wood framing applications. Designed for both professional contractors and do-it-yourself builders, this 0.220-inch shank diameter, 8-inch structural screw combines a SawTooth point, bold threading, and a corrosion-resistant finish to make wood-to-wood connections faster, stronger, and more reliable. Whether you are tackling timber framing, crating, or general structural wood fastening, this screw meets IRC and IBC code requirements as listed in IAPMO UES ER-192.

Key Features

• SawTooth Point - starts fast, reduces installation torque, and eliminates the need for predrilling in most applications, saving time on the job site.
• Bold thread design with 5 TPI and 3-inch thread length - delivers superior holding power in wood-to-wood connections, creating strong, lasting structural joints.
• Double-Barrier Coating (Tan finish) - provides corrosion resistance equivalent to hot-dip galvanization, making this screw suitable for certain exterior and preservative-treated wood applications where moisture resistance matters.
• Large washer head (0.760-inch head diameter) - distributes clamping load over a wide bearing area, reducing the risk of surface damage and improving connection integrity.
• T40 6-Lobe drive type - provides positive bit engagement, making the screw easier to drive while improving driver bit life and reducing cam-out.
• Code listed in IAPMO UES ER-192 - meets 2018 and 2021 IRC and IBC requirements for most common wood framing applications, giving you confidence in compliance on inspected projects.
• Underhead nibs - allow the washer head to seat flush to the wood surface with reduced splintering, producing a clean, professional finish.
• Size identification on the screw head - makes it easy to confirm you are using the correct fastener during installation, reducing costly mistakes.

Why This Product

• Replaces lag screws and through-bolts without predrilling - the SawTooth point and optimized thread geometry mean you can drive directly into most wood materials, cutting installation time and the number of tools required on the job.
• Corrosion resistance built for exterior and treated-wood use - the Double-Barrier Coating delivers protection equivalent to hot-dip galvanization, making this timber screw a dependable choice for outdoor structures and preservative-treated lumber applications.
• Engineered for code-compliant structural connections - with IAPMO UES ER-192 code listing and compliance with IRC and IBC requirements, this screw is backed by third-party evaluation for use in inspected residential and commercial wood framing projects.
• Versatile for contractors and DIYers alike - the T40 6-lobe drive, self-starting point, and washer head work together to make installation straightforward whether you are an experienced professional or a first-time builder tackling wood-to-wood fastening or crating work.

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter: 0.220 in.
• Length: 8 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: Tan

Available Pack Options

• SDWS22800DB-R12: 12 Pk - includes one 6-lobe, T40 driver bit
• SDWS22800DB-R50: 50 Pk - includes one 6-lobe, T40 driver bit
• SDWS22800DBMB: 250 Pk - includes one 6-lobe, T40 driver bit
• SDWS22800DB: 400 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

Does this screw require predrilling before installation?

In most applications, predrilling is not required. The SawTooth point is specifically designed to ensure fast starts and reduce installation torque, allowing the screw to drive directly into wood without a pilot hole in most common wood framing situations.

Is this timber screw safe to use with preservative-treated lumber and in exterior applications?

Yes. The Double-Barrier Coating provides corrosion resistance equivalent to hot-dip galvanization, making it suitable for certain exterior and preservative-treated wood applications as described in the IAPMO UES ER-192 evaluation report.

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

This screw uses a T40 6-lobe driver bit. A T40 driver bit is included with SDWS screws. For best results, use a low-speed 1/2-in. drill paired with the T40 6-lobe bit to maintain positive engagement and extend bit life.

What building codes does this screw comply with?

This screw is code listed in IAPMO UES ER-192 and meets IRC and IBC code requirements for most common wood framing applications, making it appropriate for use on inspected residential and commercial construction projects.