The development of the 4 x 2 floor truss system revolutionized the truss industry. Plating to the narrow edge of the chord members presented some issues, but all in all it allowed component fabricators another product offering, expanding their potential business. In the original designs, it was intended that the center of the floor truss be designed as a floating chase – the definition being a space or area that could adjust to the variation of lumber thickness and web lengths. As equipment improved and created repeatable accuracy in cutting, the need for a “floating or self-adjusting” opening became less important but still valuable as lumber thickness still varied and required adjustment. The builder demand for the open web system lent itself to plumbing and heating, ventilation, and air conditioning, and naturally these trades started to utilize the openings more and more. In fact, it wasn’t long before plumbing and HVAC started dictating where the chases needed to be, often requesting difficult locations or expensive configurations that required higher-grade lumber and multiple chord segments.
The interesting thing about our industry is that, as the capabilities evolved, often the component manufacturers did not recoup the additional manufacturing cost associated with special or specific designs. Recently, while dealing with a client’s customer, I realized my client was holding chases and increasing labor cost for projects the end user did not need. Worst yet was that the fabricator was not getting paid for the features his design group was implementing “because the software could do it.”
The simple lessons here are as follows:
- Always float your floor truss chases, if possible.
- Floating the chase helps to deal with variable lengths and thicknesses of lumber.
- Floating the chase rather than holding the chase improves the quality of the member-to-member gaps of floor web members, thereby reducing deflection and creep.
- Holding chases often requires special “cut-to-fit” situations at the floor machine.
- Most HVAC mechanics do not use the center case but instead prefer closer to the end of the truss which is nearer the bearing wall.
- Fixed chase locations can create several cut-to-fit web members, increasing the time required to build the floor truss.
- If you have to match chases, get paid for it – and not just material cost but include the extra labor and time.
- Unless the customer asks for fixed chases, provide floating chase designs. Often when you ask them, they say fixed because they don’t understand how the chases will be used.
- Chases should be centered in the floor truss utilizing “standard” webbing, removing special cuts and odd webs as much as possible.
- Review any repeat projects with your clients to see how they are using your product – that will provide you with a wealth of information you can use to improve your relationship with them.
Remember that, just because the software can do something, it never hurts to ask if you should do it. While keeping an eye on your quality, it’s also good to keep an eye on your bottom line.
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.