Hi Avraham,

As you know after learning the Sugya in Yoma (besides the Sugyos in Menachos and more), there are a lot of opinions and details regarding the Chiyuv of Mezuzah in places that aren't used for regular housing.

Let me just offer the main idea, which can help making sense in all this maze.

The first question we ask is, if the place in question qualifies as a Dirah - a place of regular living. We can understand that if we live in a 3-bedroom apartment and one room is just used for a few hours during the day for esoteric uses as storage etc., we will not say that this room has a separate status, and the whole apartment is under one category. Now, what if this storage room is out in the yard, but is regularly used together with the main house, is this room part of the Dirah, or is it a separate place. We see that if women of the house use this separate room as a washroom or for make-up etc., is this a good enough purpose to consider this room as a part of the Bayis The word 'Baisecha' teaches us this criterion, that only a room that is used for housing or regular living, is Chayav. That is why a chicken roost, which was at that time used regularly as part of the kitchen, can be considered part of the Bayis.

The second question is, wether the specific door or gate is considered an entrance to the Dira. After we decided what is part of your Bayis, we now turn to decide what is an entrance to that Bayis. Is it the patio in front of the house considered an entrance Is the entrance to your elevator considered an entrance to your house or only the actual front door to your apartment Maybe even just the 'main' door in your apartment, say, the door to the bedroom So, we learn from bi'Shearecha a wider definition for the concept of an entrance. We learn that the Achsadra or Mirpeset in front of the house is also a Shaar.

I hope this helps!

Kol Tuv,

Aharon Steiner