Bava Metzia 117

Build back better.

mishnah on the bottom of yesterday’s daf states that if a two story building collapses and the stories are owned by different people then they share the financial cost of reconstruction. Specifically, the owner of the lower story provides the materials for their ceiling, and the resident of the upper story provides materials for their floor. Each pays to rebuild the portion of the building they own.

Today’s Gemara asks whether it’s acceptable to build back a structure that differs from the original building. We first tackle scenarios where the lower-floor resident wants to make improvements:

Rav Aha bar Adda says in the name of Ulla: In the case of a resident of the lower story who seeks to rebuild it with untrimmed stones (that are larger than the original hewn ones), the court listens to him. But if the house was previously built with large untrimmed stones and he now wants to rebuild it with smaller hewn stones, the court does not listen to him.

Increasing the size of stones used in building the first floor will increase stability for the upstairs neighbor, and therefore the court — which can issue building permits — will allow it. But if he seeks to rebuild with smaller stones which are less stable, the court will not permit it. Likewise:

If the house was formerly built with bricks, and he wants to rebuild it with girders, the court listens to him. But if the house was previously built with girders, and he now wants to rebuild it with bricks, the court does not listen to him. 

When it comes to bearing the weight of a second story, large beams are better than bricks, so the court will allow him to make this improvement as he rebuilds. However, if beams were used in the original house (which, one must note, nonetheless collapsed), switching to a weaker material is impermissible. And so on: He must use a species of wood as strong if not stronger than the original for his roof, and he may not increase the number of windows which will also make the building structurally less sound. And he may not raise the ceiling.

Rav Aha is looking out for the upper floor resident by making sure the first floor owner doesn’t do anything to compromise the safety of the second floor. And what about the upstairs neighbor’s rebuilding options? 

In the case of a resident of the upper story who comes to change the structure, and wishes to rebuild the upper story with hewn stones instead of large untrimmed stones, the court listens to him. But if he wants to change from smaller hewn stones and rebuild with larger untrimmed stones, the court does not listen to him.

It is the job of the second floor owner to make sure they do not put lots more weight on the lower floor. Everything Rav Ulla said in the first case for the lower resident? Flip it around. They may switch to lighter stones but not heavier ones, from girders to bricks, from a heavy wood to a lighter wood, and they may add more windows. There’s only one rule here that’s the same for both residents: they can both build lower, but not higher, than what was there previously. Eight foot ceilings cannot be extended upward, since whether this is done on the first or second floor, it can create instability for the other story.

The upshot is that the collapse of a building is often tragic but also an opportunity to build something new and possibly better. It’s great to make improvements, as long as the renovation doesn’t benefit one party at the expense of the other.

Read all of Bava Metzia 117 on Sefaria.

This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on June 25th, 2024. If you are interested in receiving the newsletter, sign up here.

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