A cornerstone [which the owner] is required to remove must be completely removed. But when he [is required to] demolish it, he demolishes his [side] and leaves his neighbor’s [side]. This results in a stringency in the removal [of the stones] over the demolition [of the house]. R’ Elazar says: A house built with a main support and smaller materials [where the nega] appears on the main support, [the owner] is required to remove all of it; [where] it appears on the smaller materials, he removes his [side] and leaves his neighbor’s [side].

[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.