Reminder on roof and floor truss computations, layout plan and certification

Friday, 17 February 2017

The VBA's Inspection Services Team has issued a reminder about the importance of roof and floor truss computations, layout plans and certification (the truss details) being supplied to the relevant building surveyor (RBS) before frame construction starts.

While assessing complaints lodged with the VBA, Inspection Services found that many frame inspections are being requested by the builder and arranged by the RBS without the roof and floor truss details being supplied to the RBS before the start of frame construction.

Inspection Services also found that many building inspectors are approving the mandatory notification stage of a frame inspection without having the full truss details available on site at the time of inspection to allow for a full and accurate inspection.

In many cases, the RBS is withholding the occupancy permit or Certificate of Final Inspection because they are still waiting on the full truss details at the end of the project.

What should be done?

Roof and floor trusses are custom designed and built for each project, with individual trusses able to include design features that are important to its successful performance.

Trusses are often supported on internal loadbearing walls, have web and chord members of different sizes and stress grades, and include web stiffeners, special braces and fixings. The computations provide the individual truss specifications that need to be assessed on site to ensure they are constructed and installed according to the intended design.

What can you, as a Practitioner do?

The RBS should continue to ensure that the building permit incudes a condition that the full truss details are provided before frame construction starts. This will satisfy the RBS's obligations set out in Practice Note 2014-62.

Where the builder is requesting a frame inspection, the RBS should confirm that they have been provided with the full truss details as per the building permit. If the builder has not provided them, the RBS should advise that there can be no inspection until the full truss details are submitted for assessment; and when approved, can be given to the building inspector to conduct the frame inspection.

Builders must comply with all the conditions set out in the building permit and within the timeframes specified, including full truss details, before frame construction starts.

Building inspectors must ensure they conduct the frame inspection by reviewing all approved documentation, including the full truss details. Under no circumstances must the building inspector approve a frame inspection without reviewing this documentation approved by the RBS. Also, they must not approve the frame inspection subject to the builder providing the truss details to the RBS.

Where there has been an inspection and the full truss details were not provided to the RBS for approval, the RBS may issue an order to stop building work until they are provided so the frame can be inspected.

Note: builders and tradespeople must not modify floor or roof trusses without first consulting the truss manufacturer and having the RBS approve the design of the truss modification. The building inspector must not approve the frame inspection if truss modifications have not been assessed and approved by the RBS.

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