I don't think there is a specific name for it. As in the kwoon or guan( as in that of daoguan) just simply means a building of some sort where people gather and do a specific thing. As Dao or Tao means "The Way", a dao guan would mean a monastary. And an wuguan would mean a place where people gather to practise martial arts as wu in chinese means martial arts. Back to the point, nowadays, when people practise taiji at a place they just call it a school.
'xiao jiao' is another Chinese term occasionally used. The second half of this term means church to give the meanign of somethign sacred occuring therein.
xiao jiao? Never really heard of that before... Could you like put in the sounds in numbers for the xiao and jiao so i know which words they are exactly. Thanks!