[If the roof of] a house is split, [and] tumah is in the outer part, utensils that are in the inner part remain tahor. [If] tumah is in the inner part, Beis Shammai say: The split must be four handbreadths wide [for the outer part to remain tahor]; [whereas] Beis Hillel say: [It remains tahor even if the split] is very small. R’ Yose says in the name of Beis Hillel: A handbreadth.