What land rights, if any, does the owner of the top floor of a house have?
The Mishna on today’s daf discusses a two story house that collapses. Previous Mishnayot discussed how the bricks should be divided between the owners, and how to deal with a case where only the top floor fell down. In the case presented in our Mishna, the owner of the bottom floor is not interested in building and we find a discussion about what the owner of the top floor can do to retain his rights. Since he cannot build in the air, he can build a ground floor, and according to the Tanna Kamma, he can live in it until the owner pays him his expenses so that he can complete his own apartment.
The Gemara brings a baraita that describes a case where after the building collapse, neither of the two owners has the money to rebuild, and the individual who owns the land (the owner of the lower story) wants to sell the property. How much does each owner receive?
Rabbi Natan rules that the owner of the bottom floor receives two-thirds of the value, while the owner of the top floor receives one-third. Others suggest that they should split it differently, with the owner of the bottom floor receiving three-quarters and the owner of the top floor receiving one-quarter.
Rashi explains that the question stems from the fact that the owner of the land may want to claim that the owner of the top floor has no rights at all, since his apartment is hanging in the air and he has no claim in the land itself. The Gemara’s conclusion, which accepts Rabbi Natan’s ruling because a second floor lowers the value of the bottom floor by one-third, is understood by Rav Amram Gaon to mean that a second floor reduces the life of a house by one-third.