A ziz-type ledge on top of a doorway spreads tumah if it is a handbreadth wide. [If] it is on top of a ‘‘two-fingerbreadths window’’ [or] on a ‘‘gimlet window,’’ it has no minimum size. R’ Yose says: [It must be] equal in size.

A rod that is on top of a doorway, even if it is one hundred cubits high, spreads tu-mah no matter how narrow it is, these are the words of R’ Yehoshua. R’ Yochanan ben Nuri says: Do not treat this any stricter than a ledge.

A ziz-type ledge encircles the entire house and overlaps three fingerbreadths of the doorway. If tumah is inside the house, utensils underneath [the ledge] become tamei. [If] tumah is underneath [the ledge], R’ Eliezer rules the house tamei, and R’ Yehoshua rules the house tahor. The same applies to a courtyard surrounded by an awning.

There are two ledges, one above the other, each a handbreadth wide, and there is a cubed handbreadth between them. [If there is] tumah underneath them, whatever is underneath them becomes tamei. [If there is tumah] between them, whatever is be-tween them becomes tamei. [If there is tumah] above them, whatever is directly above it, up to the sky, becomes tamei. [If] the upper one extends beyond the lower one by a handbreadth, and tu-mah is underneath or between them, whatever is underneath or between them be-comes tamei; [if there is tumah] above them, directly above it, up to the sky, becomes tamei. [If] the upper one extends beyond the lower one by less than a handbreadth, and tumah is underneath them, whatever is underneath them or between them be-comes tamei. [If there is tumah] between them or beneath the extension, R’ Eliezer says: Whatever is underneath them or between them becomes tamei. R’ Yehoshua says: Whatever is between them and whatever is underneath the extension becomes tamei, but whatever is underneath [the ledges themselves] remains tahor.