Large spans [9.23.1.1(1)(e)]

[Inspector Gadget]

I wanted to gain insight from fellow Canadians on the application of Part 9 to large truss span buildings.
I had a plan come across my desk today that had a portion of a house with a clear span of 48 feet (14.63m). This clearly exceeds the 12.2 metre threshold set in 9.23.1.1(1)(e).
I've requested the client either provide evidence of mid-range support for the truss, or gain engineer design for the wall supporting this element. I'm also cognizant of 9.4.2.1(c), in relation to snow loads.
Wall is a standard 2x6 @ 16" (40cm) centres. An engineer has designed - but not stamped - the plans, so this ought not to be a great challenge, but I wanted to gain a second opinion on whether I'm interpreting 9.23.1.1 correctly. I found the note and the illustrated guide particularly unhelpful.

 

[tmurray]

You are correct. Anything over 12.2m needs the supporting elements engineered as well. This even applies to the trusses themselves as they can no longer comply with the relatively basic design principles in Part 9 and the roof system must be designed in its entirety to Part 4.

I actually had this discussion with a contractor a few weeks ago.