Question:
We live in a multi-family apartment in Israel (just beyond the green line). Our apartment building was built on a hillside so it is setup in such a way that all minus floors (we live on fl. -2) have a chatzer (large yard). We discovered that located directly under our house was a large empty space that we could use for a second story to our apartment if we dug in our yard. Now that we have completed digging beneath our apartment I was warned that we should check whether or not this space really belongs to us or if we would have to share some of the space with the other 20+ neighbors or possibly reimburse them somehow for its use.
A few points to consider: 1. The challal is located directly under our yardapartment with no other neighbors having access to it. 2. We live in a city in which it is very common for people to use challal for their own apartments in a similar way. 3. The city does not offer building permits for using this space so it is widely known that people build without these permits.
I would appreciate any insight that you may have on this including halachic sources or opinions of various Israeli Rabbi's on this topic if known.
Answer:
Answer from Horav Y. Fleishman shlit"a
The consensus opinion is that it belongs to all the neighbors. Rav Zafrani spoke about it at a Yom Iyun by us I believe it is printed in the עלון המשפט which is on the Hebrew site-perhaps make a deal with your neighbors since it sounds like there are lots of challals in the bldng
