Input

Basically in any construction project, WBS includes all the work to be done by the stakeholders.

In the initial stages of the project, the objectives or deliverables are not clear.

Normally a high-level WBS is prepared in the conceptual stages and when the objectives / deliverables are clear, then the high level WBS is broken down into detailed WBS.

So, in a way, most of the time, we go with top to down approach rather than DOWN to TOP.

Hope I am clear.

Cheers,

Raviraj