Before giving an idea of the ideal floor size needed for a ceilidh / barn dance, I should say that we would endeavour to use whatever space is available. If there is lots of room, we can do any kind of dance. If space is very restricted, only certain kinds of dance would be done, perhaps some people would have to wait their turn for another dance and everyone would squash up [can be quite fun!]
Setting out the room
If the dance is in the same room that the meal has been held in, or is in a marquee where there has been a meal, then typically either half the tables are removed, and the remainder are moved well back so that at least half the room is available for dancing. Don't have rows of tables so that there are tables between guests and the dance floor. They will be disconnected from what is happening and tend not to get up and dance.
Even, if the room is being dedicated to the dance, and particularly if space is tight, remove the typical clutter from the room. You don't really need tables, just some chairs round the outside of the room.
If you are having a disco, put them somewhere well away from the band if at all possible, to avoid getting the equipment tangled up.
for the band
We need enough space for the musicians, plus a table behind them to put our mixing desk, plus some space to put loudspeakers. It obviously varies dependent on the number of people in the band ie which line-up you book, how many different instruments they may each be playing and having to store, and the kind of PA equipment they have. A typical 4 piece band takes something like 2 meters deep by 4 meters wide, plus somewhere to locate the main loudspeakers.
Square Set Dances
A square set dance ideally needs an area of 3.5 by 3.5 meters, [or 4.5 by 4.5 meters for certain dances]
Long Sets [6 couples]
A six couple long set needs an area of 2 by 4 meters [or 3 by 5 meters for certain dances], plus at one end of the longset, you need and extra 3.5m for the set to dance into. (However, if you had 2 or 3 sets in series, you would still only need one lot of 3.5m to dance into).
Here the number of dancers is dictated by the space available.
How many people will dance?
How many people will want to dance at any one time? Although the first and last dance often involve everyone (if space permits), the rest of the dance may involve 40-80% of the people, depending on age range, enthusiasm, how long a day they have had, fitness, proximity of the bar etc.
Working out how big a dance floor you need.
Take the number of people at the dance, estimate the percentage you think may dance at any one time, work out the number of sets and then the space needed.
This applies to our bands: