Bava Metzia, Chapter 10, Mishnah 2. The scenario of this mishnah seems similar to the previous one: here too we are dealing with a two-story residential building that suffered a collapse. However, the similarity is misleading, and in fact, there is a major difference here.
The opening of the mishnah and its text:
The mishnah opens with the same words: "Habayit veha'aliyah shel shenayim" - a two-story building comprising a ground floor and an upper floor, ostensibly belonging to two people. But the truth is that this building has only one owner, and Rashi even changes the text and omits the words "belonging to two."
We are speaking of a landlord who lives on the lower floor, and a tenant who lives on the upper floor. "Nifchetah ha'aliyah" - the upper floor caved in. The roof remained intact, but the middle layer - what the upstairs tenant calls a floor and the downstairs tenant calls a ceiling - collapsed. Once an area of four by four tefachim has caved in, the tenant on the upper floor may claim that the place is no longer fit for habitation.
And what is the law when "ein ba'al habayit rotzeh letaken" - the owner of the building, living on the lower floor, refuses to repair the floor for the tenant above him, leaving the latter without a place to live? The mishnah rules: "Harei ba'al ha'aliyah yored vedar lematah ad sheyetaken lo et ha'aliyah" - the upstairs tenant has the right to go down and take over the downstairs space, until the landlord repairs the upper floor.
Background: The landlord's responsibility when a rented house falls:
At the end of the eighth chapter (mishnayos 8-9) the question was discussed regarding the law of one who rents out a house to another and the house falls, and the answer there depends on the wording of the commitment:
If the landlord committed to providing this specific house - the house is no longer available, but these are circumstances beyond his control and he is not obligated to repair it. While he cannot collect rent, the obligation to repair does not fall upon him.
If he committed to providing him a house, meaning any unspecified living space - he is obligated to provide him with a place to live, and if the house fell he must move him to another place or repair that same house.
Our mishnah deals with a case that is not included in those two, as they were already discussed there. The case before us is that the agreement stipulated that the upper floor tenant receives a house built specifically above the lower floor. The meaning of this, according to the linguistic nuances as understood at the time of the Mishnah, is that the lower floor is effectively subjugated to the upper floor: if the tenant cannot live upstairs, he may go down and live downstairs. This is therefore a limited and unique case.
The dispute between Rabbi Yosi and the Sages regarding the scope of the repair:
The mishnah continues: "Rabbi Yosi omer: hatachton noten et hatikrah veha'elyon noten et hama'azivah" - Rabbi Yosi says the lower resident provides the ceiling and the upper resident provides the plasterwork. Rabbi Yosi argues regarding what exactly the downstairs tenant is required to repair:
Rabbi Yosi's opinion: The lower tenant must repair the ceiling alone, meaning the wooden beams that form his ceiling. But the plasterwork - the plaster that creates a smooth floor - is the responsibility of the upper floor tenant. In his opinion, the plaster that creates the flooring is a purely cosmetic matter, and as long as the floor is functional and stable to stand on, its roughness is not the downstairs tenant's problem.
The opinion of the Sages, and the halachah: The plasterwork is also part of the structure and what holds the building together, and a floor cannot exist without the plaster that smooths it. This is not a cosmetic matter but a structural one, and therefore the upstairs tenant may demand from the downstairs tenant not only the ceiling - the wooden beams and the like - but also the plasterwork, the plaster that smooths it.
The halachah does not follow Rabbi Yosi, but rather the opinion of the Sages, which, although not explicitly stated here in the Mishnah, can be deduced from it.
In summary: In this Mishnah, we discussed a two-story building under single ownership, where the upper story broke and the homeowner refuses to repair it - prompting the owner of the upper story to move down and live below until it is repaired. We discussed the background from Chapter 8 regarding a landlord's responsibility when a house collapses, as well as the uniqueness of this case, where the lower level is subservient to the upper level. We also learned about the dispute between Rabbi Yosi and the Sages regarding whether the plasterwork is a cosmetic or a structural matter, and the halachah follows the Sages that this too is the responsibility of the owner of the lower level.