Responsa for Bava Metzia 234:16

מי שהיה כותלו סמוך לגינת חבירו ונפל ואמר לו פנה אבניך ואמר לו

What if neither possesses [the wherewithal for rebuilding]?<span class="x" onmousemove="('comment',' So that the owner of the lower portion wishes to turn it to agricultural purposes, whilst the owner of the upper storey demands a share in it (Tosaf.). ');">¹⁵</span> (It has been taught: When neither possesses [money for rebuilding]. the garret owner has no claim at all upon the land.)<span class="x" onmousemove="('comment',' Rashal deletes the whole of the bracketed passage. on the authority of Asheri. Alfasi retains it. ');">¹⁶</span> It has been taught: R. Nathan said: The owner of the lower portion receives two-thirds [of the land], and the owner of the upper, one-third. Others say, The owner of the lower portion receives three-quarters, and that of the upper, one-quarter. Rabbah said: Hold fast to R. Nathan's ruling, because he is a judge, and has penetrated to the depths of civil law. By how much does the loft impair the value of the house [i.e., the lower storey]? — By a third.<span class="x" onmousemove="('comment',' The duration of the lower portion is lessened by one-third on account of the weight of the upper. Thus it may be held that the owner of the upper storey has a right to a third of the ground. ');">¹⁷</span> Therefore he is entitled to a third. <b><i>MISHNAH</i></b>. SIMILARLY, IF AN OLIVE PRESS<span class="x" onmousemove="('comment',' The Heb. [H], denotes the building in which the olive press, the tank, and all other objects required for pressing olives are housed. ');">¹⁸</span> WAS BUILT IN A ROCK AND ABOVE IT WAS A GARDEN, AND THE ROOF OF THE PRESS WAS BROKEN THROUGH,<span class="x" onmousemove="('comment',' Thus undermining the soil above and rendering it unfit for sowing. ');">¹⁹</span> THE OWNER OF THE GARDEN CAN DESCEND AND SOW BELOW [ON THE FLOOR OF THE PRESS], UNTIL THE PRESS-OWNER REPAIRS THE VAULTING [TO PROVIDE A SUPPORT FOR THE GARDEN ABOVE]. IF A WALL OR A TREE FELL INTO A PUBLIC THOROUGHFARE AND CAUSED DAMAGE, HE [ITS OWNER] IS FREE FROM LIABILITY. BUT IF HE WAS GIVEN A [FIXED] TIME TO CUT DOWN THE TREE OR PULL DOWN THE WALL, AND THEY FELL: IF WITHIN THE PERIOD, HE IS NOT LIABLE; AFTER THAT PERIOD HE IS LIABLE. IF A MAN'S WALL WAS NEAR HIS NEIGHBOUR'S GARDEN AND IT COLLAPSED [INTO THE GARDEN], AND WHEN HE DEMANDED, 'REMOVE YOUR STONES', HE REPLIED,

Teshuvot Maharam