Responsa על בבא בתרא 44:3

Q. When the brothers A, B, and C divided among themselves the house they formerly held in common, a certain wall upon which heavy beams were resting crosswise, fell to A's portion. These beams extended beyond the wall into B's and C's portions on one side, and into A's portion on the other side. A cut off those parts of the beams which extended into his rooms. B and C objected to this act on A's part.
A. Those parts of the beams which extended into A's portion belonged to him exclusively, and he had a right to cut them off, especially since the intervening wall belonged to him. Although the act of sawing and chopping weakened B's and C's structures, since the extension of the beams into A's room served no useful purpose to B and C, and because of their unnecessary weight were even detrimental, A had a right to cut them off. In any event, B and C are not entitled to any compensation for their loss, now that the act has been done.
SOURCES: Am II, 198.

Q. B constructed a stone duct near A's wooden house. A objected and B made a written promise to compensate him for any damage the duct might cause to his house. A now demands that B remove his duct because it occasionally permits water and sewage to flow into his house, and he objects to being forced to sue for damages every time it occurs. B claims that water flows into A's house only when the duct breaks. He promises to keep the duct in good condition, but refuses to remove it.
A. B must remove his duct from A's wall for a distance of 3 tefahim (hand-breadths). If the water should, nevertheless, continue to flow into A's house, it is for A to protect his wall by whatever means he sees fit, but he can demand nothing of B.
SOURCES: Cr. 3, 4; Pr. 92; L. 357; Mord. B. B. 520.