What is the ruling when wood or a building is found on jointly-owned or a neighbor's wall without knowledge of the cause?

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If one's building or wood is found on a shared wall or a neighbor's wall, and the cause is unknown, the owner retains the right to restore it if it is removed. This is because the apparent situation is that the placement occurred legitimately, whether through settlement or other means, and this presumption stands unless the contrary is established. Likewise, if a water drainage channel (masil) or roof water runoff drain is found on another's land, the established right persists, treating it as an established possessory right (yad thabita).