Komentarz do Negaim 13:2

האבן שבזוית – that is between him and his neighbor jointly.

In the case of a stone in a corner, when the stone is taken out it, he must take it all out; But when [the house is] torn down he tears down his own [part] and leaves that which belongs to his neighbor. Thus it follows that there is a greater stringency for taking out than for tearing down. The stone at the corner of a wall is a large stone shared by two houses. If one side is afflicted with a nega and he has to remove that stone only, he takes out both sides of the stone, even though the side that is in his neighbor's house does not have a nega. However, if the law mandates that his whole house be torn down, then he need not remove both sides of the stone. An explanation for this would seem to be that when the Torah mandates the removal of the stone, the whole stone must be removed. But if it mandates tearing down the house, only the house must be torn down. The side that is on his neighbor's side need not be torn down. We should note that this same rule applies to other stones shared by both houses. It only uses the example of the cornerstone because this would have been common.

חולץ את כולו – for when they (i.e., the Rabbis) expound "וחלצו /]“the priest shall order the stones with the plague in them] to be pulled out,” (Leviticus 13:40 – with a plural construction), teaching that both of them pull out/tear out [the stones].

Rabbi Eliezer says: if a house is built of rows of head stones and small stones, and a nega appears on a head stone, all of it must be taken out; but if it appeared on the small stones, he takes out his stones and leaves the others. Albeck explains that the walls of their houses would have stones with "heads" that jut out on both sides of the wall. Between the "head stones" would be other stones that are also visible from both sides of the house. However, these stones would go into the wall and be subsumed inside the head stones. If the nega appears on the head stones, all of the stone must be removed. Similarly, if he has to tear down the house, all of the head stone must be torn down. However, if it occurs on one of the small stones, he only needs to remove his own side; the stone on the other person's side need not be removed.

בזמן שהוא נותץ (and at the time when he has to tear down – see Leviticus 13:45) – the entire house.

נותץ שלו – for concerning cutting out/breaking up, it is written (Leviticus 13:45): “its stones and timber”/”את אבניו ואת עציו" , its stones that are his and its timber that is his.

ראש ופתין (if a [twin] house is built with cross-beam and king-beam/principal beam common to both compartments) – it explains in the Arukh, that particular stone or that piece of wood that takes hold from the western side of the course of stones is his, and of the eastern side, the course of stones is his neighbors, he put the stone or that piece of wood is the cross beam. And those stones and pieces of wood that are in this course of stones on the west is one, and that course of stones in the east is one, for they are from the principal beam common to both compartments.