Frequently Asked Technical Questions
Consider this statement from a set of construction contract documents: “The Truss Manufacturer is responsible for inspecting the truss installation, bracing, anchorage and bearings and preparing a letter of verification stating that trusses are installed and braced properly.” At first glance, it may seem that the truss manufacturer is the most logical party to perform such an inspection. They are the truss experts, are they not? But on second thought, why is the truss manufacturer singled out to perform installation inspections of their products when they have no control over the installation process? Is the same service required from the window supplier, the concrete supplier or the plumbing contractor? There is no good reason for a truss manufacturer to supply framing inspections. If the justification for the request is the lack of knowledge on the part of the end user or building inspector, then education is in order instead of more risk exposure for the truss manufacturer.
Consider the following question and answer the next time you are asked to provide a jobsite inspection. By sending an independent engineer to inspect trusses, beams, and hardware that we, the truss manufacturers, supplied, could we be held responsible for other components of the building or the entire building itself? Also, where would the responsibility of our inspecting engineer end if he or she noticed, for example, a column supporting a girder was not adequate?
Are trusses required to have tags on all bearings that are not at the heel location? What about tags on webs requiring lateral reinforcement?
What do you mean by the term “trusses”? Are there different kinds of trusses? What are their uses?
What is the history of the topping off or topping out ceremony when the top floor is completed and a tree is placed on the roof?
Do you have information on purlin grades and species to meet 50 psf top chord live load using 2x4s on edge 24 in. O.C. over trusses at 6 ft. O.C.?
IBC 2012/2015 2303.4.6 and IBC 2012/2015 2303.4.7 state:
2303.4.6 TPI 1 specifications. In addition to Sections 2303.4.1 through 2303.4.5, the design, manufacture and quality assurance of metal-plate-connected wood trusses shall be in accordance with TPI 1. Job-site inspections shall be in compliance with Section 110.4, as applicable.
2303.4.7 Truss quality assurance. Trusses not part of a manufacturing process in accordance with either Section 2303.4.6 or a referenced standard, which provides requirements for quality control done under the supervision of a third-party quality control agency, shall be manufactured in compliance with Sections 1704.2.5 and 1705.5, as applicable.
Does this clause make it mandatory to be in a quality control program and have an “approved” inspection agency to provide trusses to jurisdictions that have adopted this code? What defines an approved inspection agency?
I'm trying to find out who the truss manufacturer was that built the trusses in my home. I was told that there is usually a stamp on the side of the bottom chord. All I found was “2400F 2.0E.” What am I looking for? The other chords only have material stamps. Can you tell me what kind of information I should be looking for to find out who the manufacturer was?
During a home inspection, the inspector stated that the spacers were not secured at the attic trusses. What did the home inspector mean by this?
How do I go about estimating the weight of a roof truss framing system? Is there a table of span vs. pitch vs. weight of trusses? Is there a guide available that shows how the components of various roof styles (hip, gable, etc.) are commonly framed and the associated terminology?