By Rabbi Chaim Chazzan
A group of people bought condos in a building and share ownership of the hallways. The owner of the only apartment on the top floor wishes to extend his apartment by closing in the hallway, and claims that the other residents will lose nothing for that space is only used to enter his apartment. Some of the other residents refuse to give consent. Must the owner of the top floor apartment take their objection into consideration?
One who lived in another’s property, without the owner’s permission, is exempt from paying when the said property is not usually rented out. Although by doing so, the squatter has saved himself from paying rent for the time he resided in the other’s property, we say “zeh nehneh” – the squatter benefited – “vezeh lo chaser” – the owner lost nothing, and the squatter is therefore exempt.
Many rishonim hold that this exemption applies only after the fact, but regarding a current situation, the owner may refuse to allow the squatter to live in his property even if he will lose nothing. If the squatter then ignores the protest of the owner, he would be obligated to pay.
However, other rishonim hold that Beis Din can force the owner to allow the squatter to live there for free in a case where the owner could not rent out the property even had he wanted to, based on the principle that we force a person not to behave like the people of Sedom (where they would refuse to assist others even at no cost to them).
Practically, poskim rule that since it is an unresolved dispute, we are unable to obligate one to allow another to use his property, for he can say, “I hold like the first opinion which says that an owner cannot be forced (‘kim li’).”
Moreover, even according to the second opinion, we can only force the owner to allow another to use the property, but it would never be permissible for the squatter to build on the property. For even though the owner is unable to use it, we cannot force him to completely forfeit his property.
In the case of the penthouse top floor apartment, it would follow that the owner cannot evoke the principle of ‘kofin al middas Sedom’ to force the other residents to agree to his extension, since (1) the issue is an unresolved debate and (2) because the extension results in the others being deprived of their property.
However, some batei dinim do force neighbors to agree in such circumstances. Perhaps their reasoning is that they see shared property as being there for the benefit of the residents. If for whatever reason the builder did not utilize a particular space, and later it becomes possible to take advantage of that space (for all the residents or for one of them), no claim can stop it from being used.
 ב”ק כ ע”א ואילך וברש”י ותוס’. חו”מ סי’ שסג ס”ו.
 תוס’ ב”ב יב ע”ב ד”ה כגון ובב”ק שם ד”ה הא מתהנית, נמו”י ב”ק דף ח’ ע”ב מדפי הרי”ף בשם הרא”ה, וכמותם פסק המחבר שם.
 מרדכי ב”ק סי’ טז בשם יש מפרשים וכמותם פסק הרמ”א שם.
 עמק המשפט שכנים סי’ א סעי’ יח בשם שו”ת מהרש”ם ח”ב סי’ קנג.
 ספר משכן שלום שכנים פ”ו ענף ב סעי’ יט.
 כן מביא בשו”ת שבט הלוי ח”ח סי’ רצט ולא מצא להם טעם ברור.
 כן ביאר בספר משכן שלום הנ”ל פ”ו ענף ו’ במילואים סעי’ ס.