How to Connect Mass Timber Panels with Steel Instead of Plywood

Simpson Strong-Tie has developed a faster, easier and more economical way to connect CLT and other types of panels on mass timber projects. Introducing the LDSS light diaphragm spline solution, featuring a steel spline strap that replaces traditional plywood splines.

Eliminate CNC routing and save procurement time

The solution has four components that simplify and speed up panel connection work — the LDSS light diaphragm spline strap, PRO300SG2 Quik Drive® tool, unique noseclip and collated Strong-Drive® WSV screws.

Unlike plywood splines, which require routing of the panel surface, the LDSS light diaphragm spline strap is placed directly on top of panels. By eliminating CNC routing, manufacturers can save significant time and cost on fabrication. Another consideration is that plywood must be sourced separately from other structural connections on a project, and requires additional labor to cut each connection to the correct width. However, the steel LDSS strap is easily procured in strips that are 3.75″ wide. Taken together, these improvements save time and money for CLT manufacturers and contractors alike, resulting in a superior solution at a lower installed cost.

Connect CLT panels securely without moisture damage  

The LDSS spline strap is constructed of steel and designed with embossed holes, enabling it to achieve high loads with an economical usage of fasteners. Tested for in-plane shear values, this steel strap is less susceptible to damage from moisture during construction, another advantage over plywood.

Fastening the LDSS spline strap with the Quik Drive tool, noseclip and collated screws is a cinch. The Quik Drive tool does away with pneumatic nailers or hand-driven screws to reduce fatigue, increase safety and save time at the jobsite. The embossed holes in the strap help guide the noseclip into position for accurate placement of each screw.

Make the switch to a steel spline solution

The Simpson Strong-Tie® LDSS spline solution is the first and only complete steel spline solution for mass timber available on the market today. Our solution is tested, widely available and backed by expert service and technical support. With it, manufacturers and contractors have a faster, easier and more economical way to connect CLT and other types of panels on mass timber projects.

Switch to the LDSS spline solution for your next design. To learn more about all of our products, visit or call (800) 999-5099.

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