The number of guests varies per construction milestone:
First pile: compact core group (client, project team, architect, local council). 30 to 80 guests.
Topping out: broader (full construction team, future users, local stakeholders). 50 to 150 guests.
Handover: broadest (clients, press, neighbourhood residents, potential customers). 100 to 500+ guests.
That build from exclusive to inclusive creates momentum. More in our article on celebrating construction milestones.