Question: Does a balcony require a Mezuzah? Why? And on which side, does one need to affix it if so?
Answer: In order to place a Mezuza hand say the blessing one needs an entrance with a ceiling of the size of two meters by two meters. Regarding a balcony - if the balcony is a closed one which does not have an exit to a yard, one should place a Mezuzah on the right door post upon entering from the balcony to the house. If the balcony has an exit to a yard there are different opinions - Harav Kook Zt"l placed a Mezuzah on the right door post (when entering the house). It is advisable to act as is done in the community.