Do You Know If Your Floor Machine Needs Attention?

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Issue #12253 - August 2020 | Page #35
By Glenn Traylor

The old joke is: “What time is it when an elephant sits on your fence? Time to get a new fence.”

So what time is it when your floor trusses look like this? It might be time for a new floor machine or at least some attention. In the photo [See PDF or View in Full Issue], the floor trusses were manufactured using an older model floor machine. The machine has seen better days. The truth of the matter is that, even in its better days, this problem was commonplace with its design. What was the problem? Well, there could be multiple problems. Here are some in the order of probability.

  1. It is common now to get twist and bows in your floor truss chord materials. It is a fact of life. Grading rules allow some twist in #2 lumber and it can exist in even higher grades.
  2. The floor machine air pressure or jigging may be inadequate to provide sufficient pressure to push the lumber into place.
  3. Additional verticals might be necessary to provide control of the floor truss height allowing additional pressure to be applied to the clamping system.
  4. Workers are not knowledgeable about the importance of tight joints.
  5. Verticals might not be cut square. Verify angles are 90 degrees and are not skewed.
  6. The floor machine bars used to provide clamping have twisted over time creating improper force along the top of the face, the place where the connectors are applied.
  7. Roller guides or cam followers of the floor machine pressure rods need to be rebuilt or reconditioned so pressure is squarely presented to the chords.

Be certain, ANSI/TPI 1 does not allow for gaps like this. In fact, to obtain a suitable floor surface, chords should fit tight and snug against the web members. Where one side hits and the other side does not, it creates an uneven surface to attach the floor or roof sheathing. The undulation can create waves in the surface that exaggerate the error. These situations prevent proper adhesion of mastics and create potential gaps between the chord and the sheathing, causing subsequent squeaks in the floor system. On many occasions, I have witnessed truss builders adding wedges or jamming material into the clamping to force the tight connection. This could be a great indicator that a floor machine evaluation is in order.


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.

Glenn Traylor

Author: Glenn Traylor

Structural Building Components Industry Consultant

You're reading an article from the August 2020 issue.

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