The stove bases of householders which collapsed: [If it was] less than three handbreadths, it is tamei, since one heats it from below and the pot up above will cook, [but if it was] more than that, it is tahor. [If] one inserted a stone or a pebble it is tahor. [If] he plastered it with clay, it will be susceptible to tumah from then on. [And] this was the response of R’ Yehudah regarding the oven that was placed over the mouth of a pit, or over the mouth of a cistern.

A shelf that has a receptacle for pots is tahor as a stove but tamei as a utensil with a receptacle. [Regarding] its sides: That which touches [the walls] is not tamei as a stove. [Regarding] its wide [side]: R’ Meir rules [it] tahor and R’ Yehudah rules [it] tamei. The same applies if one turns over a basket and builds a stove on it.

A stove that split along its length is tahor, but [if it split] along its width it is tamei. A kupach that split either along its length or along its width is tahor. The courtyard of a stove: When it is three fingerbreadths high it contracts tumah via contact and via airspace, [but if it is] less than this [then] it contracts tumah via contact but does not contract tumah via airspace. How is it measured? R’ Yishmael says: One places the spit from top to bottom and [the area] opposite [the spit] contracts tumah via airspace. R’ Eliezer ben Yaakov says: [If] the stove became tamei, the courtyard becomes tamei, [but if] the courtyard became tamei, the stove does not become tamei.

[If the courtyard] was separate from the stove: When it is three fingerbreadths high, it contracts tumah via contact and via airspace, [but if it is] less than this, or it was flat, it is tahor. The feet of a stove: Three of three fingerbreadths contract tumah via contact and via airspace, [but if they are] less than this [then] they are certainly tamei, and even when they are four.