A board placed over the mouth of a new oven, overlapping it on all sides to the extent of a handbreadth, If there is uncleanness beneath [the board], vessels above it remain clean; If there is uncleanness above it, vessels beneath it remain clean. In the case of an old oven, they become unclean. Rabbi Yohanan ben Nuri declares them clean. [If the board] is placed over the mouth of two ovens, if there is uncleanness between them, they become unclean. Rabbi Yohanan ben Nuri declares them clean.

Netting placed over the mouth of an oven, [so that it is] closed with a sealed lid: If there is uncleanness below [the netting] or above it, everything becomes unclean; But what is directly [above] the air-space of the oven remains clean. If there is uncleanness directly [above] the air-space of the oven, everything directly above it even to the sky becomes unclean.

[In a case where] the board is placed over the mouth of an old oven projects from either [end] to the extent of one handbreadth but not from the sides: If there is uncleanness under one end [of the board], vessels [under] the other end remain clean. Rabbi Yose declares them unclean. A betach does not bring uncleanness. If there was a projection in it: Rabbi Eliezer says: it [still] does not bring uncleanness. Rabbi Joshua says: we look at the betach as if it is not there, and the projection above brings uncleanness.

[With regard to] the shoe of a cradle, for which a hole had been made [in the ceiling to bring it] into the house [below], If [the hole] is one handbreadth square, everything becomes unclean; But if it was not [one handbreadth square] its [uncleanness] is reckoned as one reckons with [cases of contact with] a corpse.

[With regard to] the roof beams of a house and of the upper story which have no plaster ceiling upon them and are in a line, [the upper ones exactly above the lower]: If there is uncleanness beneath one of them, all beneath that one becomes unclean. If it is between a lower and an upper [beam] what is between them becomes unclean. If it is above the upper [roof beams], what is directly above to the sky becomes unclean. [In the case] where the upper [roof beams] were [over the gaps] between the lower [roof beams]: If there is uncleanness beneath one of them, what is beneath all of them becomes unclean; If above them, what is directly above to the sky becomes unclean.

[With regard to] a beam which is placed across from one wall to another and which has uncleanness beneath it: If it is one handbreadth wide, it conveys uncleanness to everything beneath it; If it is not [one handbreadth wide], the uncleanness cleaves upwards and downwards. How much must its circumference be so that its width should be one handbreadth? If it is round, its circumference must be three handbreadths; If square, four handbreadths, since a square has a [circumference] one quarter greater than [that of] a circle.

[With regard to] a pillar lying [on its side] in the open air, If its circumference is twenty-four handbreadths, it brings uncleanness to everything under its side; But if it is not, the uncleanness cleaves upwards and downwards.

If an olive-sized portion of a corpse is stuck to the threshold: Rabbi Eliezer declares the house unclean. Rabbi Joshua declares it clean. If it was placed beneath the threshold, the [case] is judged by the half [in which the uncleanness is found]. If it is stuck to the lintel, the house becomes unclean. Rabbi Yose declares it clean. If it was in the house, a person touching the lintel becomes unclean. [As for] a person touching the threshold: Rabbi Eliezer declares him unclean. Rabbi Joshua says: [if he touches it at a point] below a handbreadth [from the surface] he remains clean; above that handbreadth he becomes unclean.