The Simpson Strong-Drive SDWS Timber Screw (Interior) in 0.220-in. diameter by 5-in. length is a structural wood fastener engineered for cross-laminated timber construction, mass timber assemblies, and general interior wood framing applications. Finished in a black E-coat electrocoating, this heavy-duty structural screw combines a low-profile washer head, serrated threads, and a SawTooth point to deliver fast, reliable installation with less effort than comparable lag screws - making it a practical choice for timber-to-timber connections and demanding framing tasks.

Key Features

• SawTooth Point - cuts into wood fibers aggressively for fast starts and reduced installation torque, eliminating the need for predrilling in most applications and speeding up the job significantly.
• Serrated Threads at 5-1/4 TPI - the serrations reduce wood splitting and minimize damage to the surrounding material, preserving structural integrity in timber members.
• Low-Profile Washer Head (0.760-in. diameter) - the large bearing surface pulls members together tightly without the need for extra washers, reducing hardware count and simplifying installation.
• T40 6-Lobe Drive - provides positive bit engagement that reduces cam-out, making the screw easier to drive consistently and extending bit life during high-volume installations.
• E-coat Electrocoating Finish - a uniform black coating that protects the fastener surface and gives it a clean, finished appearance suited for interior structural applications.
• 0.220-in. Shank Diameter with 3-in. Thread Length - the substantial shank diameter delivers strong load-carrying capacity, while the 3-in. threaded section provides deep, secure engagement in the receiving member.
• Code Listed in IAPMO-UES ER-192 - meets 2018 and 2021 IRC and IBC requirements for most common wood framing applications, giving contractors and inspectors confidence on regulated job sites.

Why This Product

• Designed specifically for mass timber and cross-laminated timber (CLT) - the SDWS Timber screw is purpose-built for the structural demands of CLT panels and mass timber framing, where standard screws fall short on load performance and code compliance.
• Installs faster than comparable lag screws - the SawTooth point and serrated threads reduce installation torque and eliminate the extra step of predrilling in most wood applications, saving significant time on large timber projects.
• No extra washers required - the large-diameter, low-profile washer head creates sufficient bearing area on its own, cutting down on loose hardware and keeping the connection clean and code-compliant.
• Meets current IRC and IBC code requirements - with IAPMO-UES ER-192 listing and compliance with 2018 and 2021 building codes, this fastener supports permitting and inspection on residential and commercial projects without additional engineering justification for most common framing applications.

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter (in.): 0.220
• Length (in.): 5
• 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

Available Pack Options

• SDWS22500-R50: 50 Pk - includes (1) T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)
• SDWS22500: 250 Pk - includes (2) T40, 6-lobe driver bits (replacement bit: BIT40T-134-R2)

Approved Applications

• Cross-laminated timber (CLT) construction and panel connections
• Mass timber construction assemblies
• General interior wood framing applications
• Structural wood-to-wood connections where IAPMO-UES ER-192 listed fasteners are required
• Applications requiring compliance with 2018 and 2021 IRC and IBC building codes

Frequently Asked Questions

Does this screw require predrilling before installation?

In most applications, predrilling is not required. The SawTooth point is designed to cut into wood fibers quickly, reducing installation torque and enabling the screw to self-start without a pilot hole in most timber materials.

Is this screw code listed for structural framing applications?

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

What bit is needed to drive this screw?

This screw uses a T40 6-Lobe drive. The 6-lobe design provides positive engagement between the bit and the screw head, reducing cam-out and improving bit life during installation.

Is this screw suitable for exterior or treated lumber applications?

This version of the SDWS Timber screw features an E-coat electrocoating finish and is intended for interior applications. For exterior or treated lumber use cases, a different coating or product variant designed for those conditions would be appropriate.