The Simpson Strong-Drive SDWS Timber Screw in 0.220 in. diameter by 11 in. length is a heavy-duty structural wood fastener engineered for cross-laminated timber construction, mass timber assemblies, log-home construction, and general interior wood framing applications. Finished in a durable black E-coat electrocoating, this large-format structural screw delivers secure, high-load connections in wood-to-wood fastening scenarios where performance and ease of installation both matter. With a low-profile washer head, serrated threads, and a SawTooth point, it drives faster than comparable lag screws and pulls timber members together tightly without the need for pre-drilling in most applications.

Key Features

• SawTooth Point - aggressive tip geometry ensures fast starts and reduces installation torque, eliminating the need for pre-drilling in most applications so you save time on every connection
• Serrated Threads at 5-1/4 TPI - thread design actively reduces splitting and wood damage as the fastener drives, keeping structural members intact even in dense timber assemblies
• 0.220 in. Shank Diameter with 3 in. Thread Length - heavy structural shank delivers strong shear and withdrawal values for demanding mass timber and cross-laminated timber connections
• Low-Profile Washer Head (0.760 in. diameter) - large bearing area pulls members together firmly without the need for additional washers, saving material cost and installation steps
• T40 6-Lobe Drive - positive bit engagement minimizes cam-out, improves bit life, and makes it easier to drive long fasteners through thick lumber
• E-coat Electrocoating Finish - uniform black coating provides a consistent, corrosion-resistant barrier suited for interior structural applications
• Code Listed under IAPMO-UES ER-192 - meets 2018 and 2021 IRC and IBC requirements for common wood framing applications, giving you confidence the fastener is approved for code-required structural connections

Why This Product

• Designed for modern mass timber construction - this screw is purpose-built for cross-laminated timber (CLT) and mass timber assemblies where large-diameter structural fasteners are required and installation efficiency is critical.
• Installs faster than comparable lag screws - the SawTooth point and serrated thread geometry reduce the torque needed to drive the fastener, so crews can complete more connections per shift without pre-drilling in most materials.
• Eliminates extra hardware at the joint - the oversized low-profile washer head (0.760 in. diameter) provides enough bearing area to pull timber members tight on its own, removing the need to stock and install separate fender washers.
• Meets IRC and IBC code requirements - with IAPMO-UES ER-192 listing, this fastener is accepted for many common wood framing applications under both residential and commercial building codes, simplifying inspection and plan review.

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter (in.): 0.220
• Length (in.): 11
• Head Diameter (in.): 0.760
• Head Type: Low Profile Head
• Drive Type: T40 6-Lobe
• Thread Type: Serrated Threads
• Thread Length (in.): 3
• TPI: 5 1/4
• Point Type: SawTooth Point
• Coating: E-coat Electrocoating
• Finish: E-coat Electrocoating
• Color: Black
• Country of Origin: Taiwan

Available Pack Options

• SDWS221100-R50: 50 Pk - includes T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)
• SDWS221100: 250 Pk - includes T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)

Approved Applications

• Fastening Wood-to-Wood
• Log-Home Construction

Frequently Asked Questions

Does this screw require pre-drilling before installation?

In most applications, pre-drilling is not required. The SawTooth point is designed to start quickly and reduce installation torque, allowing the screw to drive directly into wood without a pilot hole in the majority of cross-laminated timber, mass timber, and general interior framing situations.

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

This screw uses a T40 6-lobe drive. A T40 6-lobe driver bit is included with the product. If you need a replacement bit, the compatible replacement bit is BIT40T-134-R2.

Is this screw approved for use in code-required structural applications?

Yes. This fastener is code listed under IAPMO-UES ER-192 and meets 2018 and 2021 IRC and IBC code requirements for several common wood framing applications, making it suitable for permitted structural work where code compliance is required.

Is this screw suitable for exterior or wet-environment use?

This version of the Strong-Drive SDWS Timber Screw features an E-coat electrocoating finish intended for interior applications. For exterior or exposure-rated environments, a different coating or product series should be considered. Refer to the application category - this fastener is rated for interior use.