Simpson Strong-Drive SDWS Timber Screw - 0.220 in. diameter x 15 in. length, E-coat (Interior) is a heavy-duty structural wood screw engineered for cross-laminated timber construction, mass timber assemblies, log-home construction, and general interior wood framing applications. Featuring a black electrocoated finish, serrated threads, and a SawTooth point, this fastener is built to drive faster and with less effort than comparable lag screws - making it a practical choice for demanding interior timber work where reliable pull-down force and code compliance matter.

Key Features

• SawTooth Point - enables fast, clean starts and reduces installation torque significantly, eliminating the need for predrilling in most interior timber applications so you can work faster with less setup
• Serrated Threads at 5-1/4 TPI - the thread pattern reduces splitting and wood damage as the fastener is driven, helping preserve the structural integrity of mass timber and cross-laminated timber panels
• 0.220 in. shank diameter with 3 in. thread length - provides robust holding strength in thick timber members while the generous thread engagement locks fasteners securely in place
• Low-profile washer head with 0.760 in. head diameter - maximizes bearing area to pull timber members tightly together without the need for separate washers, saving time and material cost on large timber projects
• T40 6-lobe drive - delivers positive bit engagement that reduces cam-out and driver slippage, improving bit life and making it easier to drive long 15 in. fasteners with consistent torque
• E-coat electrocoating finish - provides a durable black coating suited for interior structural applications, protecting the fastener surface and giving a clean, finished appearance in exposed timber construction
• IAPMO-UES ER-192 code listing - meets 2018 and 2021 IRC and IBC requirements for common wood framing applications, giving builders and inspectors confidence in the structural validity of the connection
• 15 in. length - reaches through thick timber members or stacked assemblies where standard-length screws cannot achieve adequate penetration or pull-down force

Why This Product

• Designed for mass timber and CLT construction - the combination of 0.220 in. diameter, 15 in. length, serrated threads, and a SawTooth point addresses the specific demands of cross-laminated timber and mass timber assemblies where standard fasteners fall short on torque requirements or penetration depth
• Reduces installation time and labor - the SawTooth point eliminates predrilling in most applications, and the low-profile washer head pulls members flush without extra hardware, cutting steps out of the installation process on large timber projects
• Code-compliant for interior framing applications - IAPMO-UES ER-192 listing and compliance with IRC and IBC requirements means this screw is accepted on permitted structural projects, reducing back-and-forth with inspectors or engineers
• T40 6-lobe drive reduces driver fatigue and bit replacement - positive engagement between the bit and the 6-lobe recess keeps the driver seated through the full length of a 15 in. drive, protecting both the bit and the screw head when driving into dense timber

Specifications

• Brand: Simpson Strong-Tie
• Shank Diameter (in.): 0.220
• Length (in.): 15
• 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

• SDWS221500-R50: 50 Pk - includes T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)
• SDWS221500: 200 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 predrilling before installation?

In most interior timber applications, predrilling is not required. The SawTooth point is specifically designed to reduce installation torque and ensure fast starts, allowing the screw to begin driving cleanly into wood without a pilot hole in typical use.

What drive 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 a replacement bit is needed, the compatible replacement is bit BIT40T-134-R2.

Is this screw suitable for exterior or pressure-treated lumber applications?

No. This fastener features an E-coat electrocoating finish and is designed for interior applications only. It is not rated for exterior exposure or use with pressure-treated lumber in outdoor environments. For exterior or treated-lumber applications, a different corrosion-resistant coating would be required.

What building codes does this screw comply with?

The Strong-Drive SDWS Timber screw is code listed under IAPMO-UES ER-192 and meets IRC and IBC code requirements for several common wood framing applications, making it suitable for use on permitted structural projects that require documented code compliance.