Until very recently, it was extremely common for us here at Partridge to have no knowledge or involvement with a project until after it came out of Council with its DA approved.
For 95% of our projects, the architects would independently develop the DA-submission plans with their client, lodge the DA, and then contact us a few months later to sign us up for the job after the DA was approved.
Only then, once all floor levels, structural zones, and building heights had been approved and “locked in” with Council, would we as engineers then have the opportunity to analyse the structural loadpath of the building and determine the size and thickness of its structural elements. For example, we’d begin to explore the thickness of the suspended slabs; the depth of the floor joists or roof rafters; and the size of the beams that would span across large openings and support the structure above.