Regarding a stone in a corner, when the stone is removed, the whole thing is removed but when the house is demolished, the owner of the infected house only demolishes his own part, leaving the adjoining house that belongs to his neighbor. It therefore follows that there’s more stringency in removal than in demolishing. Rabbi Elazar says regarding a house of large head stones and small split stones that if a nega appears on a head stone, it must be removed entirely but if it appeared on a split stone, he takes what’s his and leaves what belongs to his neighbor.
If a house in which a nega appeared had an upper loft, the beams are considered part of the loft. If the nega appeared in the loft, the beams are considered part of the lower level. If there’s no loft, the house’s stones, wood and earth must be demolished with it but one may save the frames and the window lattices. Rabbi Yehuda says that a frame built over the house must be torn down with it. The stones, wood and earth convey impurity if they are the size of an olive, though Rabbi Eliezer Chisma says that they do so in any size.