daf bit: Bava Metzia 117

[cellio]

In a previous mishnah (116) we learned that if two own a house, one owning the ground floor and the other the upper floor, and it collapses, they share proportionally in the stones, timber, and earth. (There is an aside that if one recognizes his particular stones he can claim them. I wonder how often that comes up.) The present daf discusses issues with rebuilding, and then raises the question: what if neither has the wherewithal to rebuild? How is the land divided? Rabbah says that the owner of the lower story gets two-thirds of the land and the owner of the upper story one-third. Why isn't it proportional, as in the previous example? Because the upper story impairs the value of the lower story (by forcing it to bear the load), so the owner who bore that burden gets more. (117b)