Porch is 50 x 140 cm – do I need a mezuzah on it
You should put a mezuza on it, but it should be on the right side when you are entering it from the porch, and not the right side going out to the porch. The reason is because the porch itself does not need a mezuza, since it is less than the required amount, as it is not useable for anything, especially since it isn’t even 7 tefachim wide. However, since the porch door is an entranceway to you dining room etc. therefore according to many poskim, it would need a mezuza. The mezuza however should be put up without a bracha, as it is controversial.
Shulchan Aruch Y:D 186-13, R’ Akiva Eiger ibid, Aruch Hashulchan Y:D 186- 23, Igros Moshe Y:D 1-181, Even Yisroel 7-34, Ben Ish Chai 2 Ki Tavo 19, Mezuzos Beisecha 186-52, Shar Hatzion 106, Agur Baholecha 18-28, Chovas Hador 4-7 ftnt. 17.