All houses may contract negaim uncleanness, except those of non-Jews. If one bought houses from non-Jews, any it must be inspected as if they had then first appeared. A round house, a triangular house, or a house built on a ship, on a raft or on four beams, is not susceptible to negaim uncleanness. But if it was four-sided, even if it was built on four pillars, it is susceptible to uncleanness.

A house, one of whose walls was covered with marble, with rock, with bricks or with earth, is pure. A house that did not have in it stones, wood or earth, and a nega appeared in it and afterwards stones, wood and earth were brought into it, it remains clean. So also a garment in which there was no woven part that was three fingerbreadths square and a nega appeared in it and afterwards there was woven into it a piece of cloth three fingerbreadths square, it remains clean. A house does is not susceptible to negaim uncleanness unless there are in it stones, wood and earth.

[And how much] wood [must be in the wall for it to susceptible]? Enough to be set under the lintel. Rabbi Judah says: it must suffice to make the support at the back of the lintel. [And how much] earth [must be in the wall for it to susceptible]? Such as would suffice to fill up the space between one row of stones and another. The walls of a cattle-trough or the walls of a partition are not susceptible to the uncleanness of negaim. A house in Jerusalem or in any place outside the land of Israel is not susceptible to the uncleanness of negaim.

What is the procedure for the inspection of a house? "The owner of the house shall come and tell the priest, saying, "Something like a plague has appeared upon my house" (Leviticus 14:35). Even if he is a learned sage and knows that it is definitely a nega, he may not speak with certainty saying, "A plague has appeared upon my house," but rather, "Something like a plague has appeared upon my house." "The priest shall order the house cleared before the priest enters to examine the plague, so that nothing in the house may become unclean; after that the priest shall enter to examine the house." Even bundles of wood and even bundles of reeds [must be removed], the words of Rabbi Judah. Rabbi Shimon said: clearing keeps him occupied. Rabbi Meir said: But which [of his goods] could become unclean? If you were to say, his articles of wood, of cloth or of metal, he could immerse them and they will become clean. What is it that the Torah has spared? His earthenware, even his cruse and his bucket. If the Torah thus spared a man's humble possessions, how much more so would it spare his cherished possessions! If for his material possessions, how much more so for the life of his sons and daughters! If for the possessions of a wicked man, how much more so for the possessions of a righteous one!

[The priest] must not go into his own house to isolate it, nor may he stand within the house in which there is a nega. Rather, he must stand at the door of the house in which is there is a nega, and isolate it from there, as it is said, "The priest shall come out of the house to the entrance of the house, and close up the house for seven days" (Leviticus 14:38). He comes again at the end of the week and inspects the sign to see if it spread. "The priest shall order the stones with the plague in them to be pulled out and cast outside the city into an unclean place" (v.. "They shall take other stones and replace those stones with them, and take other dirt and plaster the house" (v.. He must not take stones from the one side and bring them to the other; nor earth from the one side and bring it to the other; nor lime from anywhere. He must not bring one stone to replace two, nor two to replace one. But he can bring two to replace two or to replace three or to replace four. From here they have said: Woe to the wicked, woe to his neighbor. Both must take out the stones, both must scrape the walls, and both must bring the new stones. He alone, however, brings the earth, as it is said, "And he shall take other coating and plaster the house." His neighbor need not join with him in the plastering.

He comes again at the end of the week and inspects the nega. If it has returned, "He shall break down the house, its stones, and its timber, and all the mortar of the house; and he shall carry them out of the city into an unclean place" (Leviticus 14:45). A spreading that adjoins [the original nega] is effective however small it may be; One that is distant must be no less than the size of a split bean. And a nega that returns in houses must be no less than the size of two split beans.