Archive: Dec 2021

What Is Machine Stress Rated (MSR) Lumber?

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Quality machine stress rated (MSR) lumber is a requirement for most construction projects. MSR lumber is graded based on mechanical stress tests that compare stiffness to bending strength. This type of lumber must also meet certain appearance standards. Roof trusses, glue-laminated beams, and wood I-beams all rely on MSR lumber for its high strength values.

Properties and Benefits of Machine Stress Rated Lumber

Generally, MSR lumber is softwood dimensional lumber assigned to various classes based on its bending strength and modulus of elasticity. Each piece must undergo daily sampling during production and be able to bend over twice its rated value. Because MSR lumber is tested using mechanical equipment rather than visual inspection, MSR ratings give a more accurate rating regarding how much stress a piece of lumber can handle.

Benefits of MSR lumber include:

  • Strength and stiffness: Each piece of MSR lumber varies little in terms of stiffness, so you can ensure the strength of your overall construction project.
  • Elasticity: MSR lumber contains sufficient elasticity to help control the bounce effect in roof and flooring structures.
  • Cost Efficiency: If your construction requires frequent repairs, you may end up spending more than the initial building costs. You can avoid incurring such costs by using MSR lumber because it has a significant margin of protection from defects and constant maintenance. Therefore, you can save thousands of dollars in repairs and contractor wages.

Machine Stress Rated Lumber Applications

In addition to roof trusses, glulam beams, and wood I-beams, MSR lumber is widely used in stressed-skin panels, commercial or industrial floor and roof systems, and more. In some cases, machine stress-rated lumber can replace concrete and steel.

Machine stress-rated lumber is most popular in engineered applications that require low variability in stiffness and strength. The main areas of application include:

  • Trusses
  • Floor or ceiling joists
  • Ceiling rafters
  • Beams

MSR Lumber from Kennison Forest Products

Machine stress rated lumber improves the reliability and performance of your engineered structures. Kennison Forest Products provides a wide selection of MSR scaffolding planks made of pine, a cost-effective material ideal for building.

At Kennison Forest Products, we distribute solid sawn scaffold wood planks that meet all mechanical stress ratings and visual grading requirements. All our scaffold planks exceed OSHA and ANSI regulations by maintaining high safety standards. Our planks are also clipped and rodded to prevent splitting. Contact us today for more details about our scaffolding planks, or request a quote to start your construction project.