Parashas Metzora · Passuk 14:34
Chabad.org — English translation + Rashi
Torah Temima points to Toras Kohanim.
English: “In a house of the land” — excluding a house built on a ship or on a raft resting on its four beams, and including a house built on wooden piles or on pillars.
Definition of a grounded house
Chazal require the structure to be fixed to the ground of Eretz Yisrael; floating or purely temporary constructions are excluded, while houses on stilts are included.