In my last post, I suggested that churches with modest, paid-for or flexible space are best poised for long-term survival. And it makes sense for a young, growing congregation to move home from time to time than lock-in to a space that would hamper it (or bankrupt it.) But how much is enough?
I've encouraged readers to use the Air Force Religious Facilities Design Guide, but it keeps moving on the 'net so download it here (PDF) now. Using its charts, it would easier to see how much space a congregation -- with a plan for its own size -- or see how many people an existing space (consider all those accommodated in converted single-family houses) can hold.
In short, it looks like a "one room chapel" -- I've preached in these -- without a narthex (lobby) would need 25 square feet per worship leader, plus 11 square feet per worshiper . . . plus toilet access. Add about 25% for a narthex, which might be just enough space for a standing coffee time. And consider the rule-of-thumb that says that a worship space is functionally full when 80% occupied.
So if you had a 20'x30' room rented, with two people leading worship (a lay preacher and a piano player, say), that means you could have a congregation of 40 before needing to go to two services or moving. Or if you reserved a narthex-like space, you'd accommodate 29 people, tops. (Raise your hands if you've moved folding chairs out of the way to make coffee hour more comfortable.) And that's about the size of many congregations in the Unitarian Universalist Association.