Parashas Metzora · Passuk 14:45
Chabad.org — English translation + Rashi
Torah Temima points to Toras Kohanim.
English: “Its stones …” — “and he shall demolish the house, its stones and its timber and all the plaster of the house” — this teaches that a house does not become tamei through negaim unless it contains stones, timber and plaster.
Three essential components
Chazal require the presence of stones, wood and earth-plaster before a structure is subject to the full demolition law of house-negaim.