A house which is not four by four hand-breadths (because it is not considered "a house") is exempt from a railing, a mezuzah and an eruv (a halachic device of "amalgamation" for Sabbaths and festivals); and it is not made an ibbur (an "outskirt") of a city (for purposes of such amalgamation), and it does not render food tevel (untithed) for purposes of tithing, and it is not allocated four ells (in a courtyard.) If one makes a vow (not to benefit) from a house, he may sit in it, and it is not subject to plague-spot uncleanliness, and it is not irredeemably sold vis-à-vis the Jubilee year, and he is not returned to from the battlefield (viz. Devarim 20:5).