Design Responsibilities

Question: 

My company supplied roof trusses for a hotel project. The building inspector shut the project down because the trusses were not designed to account for additional snowdrift loading. The construction plans did not contain any snowdrift loading information. The architect is claiming it is our responsibility to determine drift loading, therefore we must fix the problem. Do you have any documentation to help us dispute the architect’s claim?

Answer: 

Yes, SBCA’s TTB – Standard Responsibilities in the Design and Application of Metal Plate Connected Wood Trusses was developed to avoid situations just like this. This document outlines what is expected from the five parties involved in the design process—building owner, building designer, contractor, truss manufacturer and truss designer. This document is helpful in clearing up expensive misunderstandings like this one and could very well be included in your customer contracts.

In your case, the building designer may not be persuaded by this information after the fact. That is why it is smart to include this document with every bid/proposal/purchase order you submit so that your scope of work is well defined from the outset. For example, section 3.0 clarifies the building designer’s responsibilities is to provide the location, direction and magnitude of loads.

Although the guidelines of TTB – Standard Responsibilities in the Design and Application of Metal Plate Connected Wood Trusses are completely voluntary and not enforced by any agency or building code, providing it and ensuring that all the language in the specifications and/or contracts/purchase orders you use complies with it helps provide a foundation that will keep you from assuming more responsibility than is yours to take. And, if you desire to take on this “extra” work, you can more easily justify getting paid “extra” for it.

Also note that the IBC 2015 section 1603 states “The design loads and other information pertinent to the structural design required by Sections 1603.1.1 through 1603.1.8 shall be indicated on the construction documents.”

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