Originally intended as an improvement in lumber manufacturing, most dimensional lumber used for framing has a radius corner created during the planing process. The rounded corner radius is intended to make the lumber easier to handle and can improve the lumber’s performance because sharp corners can catch and dig as it is handled. Some drywall installers have commented that the radius helps installation where sharp corners can impact flatness of their walls and ceilings. Rarely is rounding done with hardwood because it removes dimension from the material and can impact utility, for example, it would create a trough between lumber widths if they were placed side by side to produce a wider surface. In the truss industry, a radius corner can impact embedment of the connector plate into the lumber. In the past, however, this was not a significant factor because edge-distance rules established by the National Design Specification® (NDS®) for Wood Construction prevented the inclusion of this area with respect to tooth holding.
The process of rounding the corners is common in the US and is referred to as “eased edge” lumber or “Easy Lumber.” This is normally 1/8” for dimensional lumber, however, lumber can be purchased with a ¼” radius. In the first photo, the lumber has a grade stamp that indicates: Roseburg NO. 2 ¼” EE D FIR KD-HT. A graphical representation of how lumber with a ¼” Eased Edge looks is shown in the diagram. [For photos and diagrams, See PDF or View in Full Issue.]
So, should ¼” EE in lumber be considered during the design process? Recently, I surveyed about 20 folks in the truss industry, from Professional Engineers to component manufacturers, and I got many different opinions, ranging from “it doesn’t really matter” to “drawings should not be sealed if ¼” EE lumber is used.”
What say you? Please consider taking a short online survey about EE lumber and its use.
What’s the Big Deal?
As shown in the next photo, the red line illustrates the ¼” Edge distance concern. Not shown is the End distance, which is ½” from the end of the member. In some respects, the eased edge creates a defect similar to wane when the lumber is put into service in components.
Here are some considerations:
- Eased Edge Lumber will impact the tooth count, and the extent of that impact will depend on the size of the radius.
- Eased Edge should be considered the same as wane when verifying tooth count.
- As always, it is important to count your teeth correctly – see my previous article, Are You Counting Your Teeth Correctly?, for more information.
- Do not count teeth located at the edge of the lumber within ¼” of the edge – refer to ANSI/TPI 1 Chapter 3 Figure 3.7-6 End and Edge Distances for more information.
- Fabrication tolerance can be increased to accommodate concerns about adequate tooth count.
- Even though Easy lumber may appear as a member-to-member gap, it should not be considered as such.
- Have a discussion with your engineer to see how they regard the use of “Easy” lumber – they may not be aware of its use and their opinion matters the most!
The Bottom Line
Eased Edge Lumber does impact design, but its impact can be minor. Make sure your organization is on the same page as your engineering services.
An ANSI/TPI 1 3rd Party Quality Assurance Authorized Agent covering the Southeastern United States, Glenn Traylor is an independent consultant with almost four decades of experience in the structural building components industry. Glenn serves as a trainer-evaluator-auditor covering sales, design, PM, QA, customer service, and production elements of the truss industry. He also provides project management specifically pertaining to structural building components, including on-site inspections and ANSI/TPI 1 compliance assessments. Glenn provides new plant and retrofit designs, equipment evaluations, ROI, capacity analysis, and CPM analysis.