[If] a house on which a nega appears has an upper story, the beams are considered part of the upper story. [If the nega] appears on the upper story, the beams are considered part of the lower story. [If] there is no upper story, [the house’s] stones, wood, and clay are demolished with it, but not the roof-tiles [lit., the rectangles] and the lattices of the windows. R’ Yehudah says: The frame built on top of [the lower story] is demolished with it. Its stone, wood, and clay render tamei as long as they are the size of an olive. R’ Elazar Chisma says: As [small as] they are.

A confined house makes [a person] tamei from within, and a confirmed [house makes tamei] from within and without. Both make tamei upon entering.

If someone builds a tahor [building, using stones] from a confined [house], and [then] nega returns to the house, he must remove the stones. [If nega] returns to the stones, the first house is demolished and the stones function as an indicator for the second house.

When a house extends over an afflicted house or a tree extends over an afflicted house, someone who enters the outer one is tahor, these are the words of R’ Elazar ben Azariah. Said R’ Elazar: If one of its stones renders tamei upon entering, the house itself should certainly render tamei upon entering.