Tearoom / teahouse
A tea room, 茶席 chaseki, is usually part of or a room in another structure. A tea house, 茶室 chashitsu, is an independently standing structure or offshoot, with Mizuya, etc. set in a Roji
The size of a tea room is formed like this: Number of full sized mats, Number of half mats, Daime.
This list show some of the more common sizes with example of rooms that has this configuration.
Koma (small rooms) 小間
Ichi jo daime (1 3/4 mats), Konnichian
Ni jo 二畳, (2 mats)
Nijo daime (2 3/4 mats)
San jo 三畳 (3 mats parallel or one at right angles to two); with kakoi (an enclosed temae area, e.g. Yodomi seki);
Sanjo daime (3 3/4 mats), etc.
Any room in which the fumikomi-tatami is also the temae-datami.
Yo Jo Han 四畳半 (4 1/2) Yuin
Rokujo 六畳 (6 mats), Daironoma, Tsuginoma
Hachijo 八畳 (8 mats), Tot’tot’sai
Hachijo daime (8 3/4 mats), Shinka