A gathering hall is sized by the largest number of people who will use it at once and by what they are doing, 1.0-1.5 m² each when seated at a meeting, 1.5-2.0 m² at dinner, 0.5-0.7 m² standing and 2 m² sleeping on the floor, so a settlement of 100 needs a main hall of about 100-150 m². The roof must then cover that floor with a clear span of 8-12 m or more and no interior columns, which is the main structural challenge.
Part of Community Gathering Hall
Capacity and structure are the two linked decisions of how big a gathering hall must be and how its roof is carried without posts in the way.
Count The People, Then Cover Them
The gathering-hall guide sizes the main hall from the activity: 1.0-1.5 m² per person for meetings where everyone sits; 1.5-2.0 m² for dining at tables; 0.5-0.7 m² for events with standing room. For emergency sheltering it uses 2 m² per person sleeping on the floor. A settlement of 100 people needs a main hall of about 100-150 m², roughly 10 × 12 m to 10 × 15 m, and a total building of about 150-200 m² with a kitchen, a store and a small room. The main hall needs a clear span of 8-12 m or more, with no interior columns, which is the building’s main structural challenge.
Three articles go deeper:
- Sizing for Settlement Population — the arithmetic, and where the figures strain at 150 people
- Large-Span Roof Structures — the forces in a truss and why spans have limits
- Emergency Shelter Capability — the hall as a refuge
What You Need
- A headcount now and the expected maximum
- The list of uses the hall must serve
- Timber, steel or both for a roof that spans the width
Method
Step 1: Decide the design population for the hall, not only today’s.
Step 2: Multiply by the largest allowance for the uses you want.
Step 3: Add the small rooms, then check the roof span you need.
Common Mistakes
- Sizing for meetings only, then finding that dinner or shelter needs more.
- Choosing a roof span without checking the carpentry.
- Forgetting that a hall that holds everyone must also let everyone out.
Safety
The whole community is in one building
A hall that holds everyone at once needs at least two exits, doors that open outward and a roof built to a higher standard than houses. Do not exceed the posted capacity.
What’s Next
- Learn next: Sizing for Settlement Population
- Combine with: Multi-Purpose Design