Yerushalmi Sukkah 1:7 ירושלמי סוכה א׳:ז׳

MISHNAH: One may use planks as roofing, the words of Rebbi Jehudah, but Rebbi Meïr forbids. If he put there a plank four hand-breadths wide it is qualified on condition that he not sleep under it¹⁶²Everybody agrees that a plank 4 hand-breadths wide, while impervious to impurity, is regularly used in roofing permanent housing, should not be used for the sukkah. But if it is put on the sides, along a wall, it is considered extension of the wall and not part of the roof and therefore disqualifies the roof only if 4 cubits wide (Note 30). The sukkah is qualified but sitting under the plank is not counted as sitting in it..

HALAKHAH: Rebbi¹⁶³As the quote later in the paragraph (Note 144) and chronology imply, everywhere one has to read Rav Jeremiah (the first generation Babylonian colleague of Rav) instead of Rebbi Jeremiah (the fourth generation head of the Academy of Tiberias.) Jeremiah in the name of Rav: They disagree if it is [four]¹⁶⁴Corrector’s addition, rectifying a scribal omission. In the argument later the numeral is in the masculine (hand-breadths); it seems necessary to consider the feminine form here as sloppy spelling, not referring to cubits. wide. Rebbi Yasa in the name of Rebbi Joḥanan: They disagree if they have been polished for implements¹⁶⁵Even if they qualify as פְּשׁוּטֵי כְלֵי עֵץ “wooden implements without concavities” which are impervious to impurity. These are excluded by tradition, as they could be seen as finished implements, not by any biblical standard. Babli 15a.. But was not Rebbi Jeremiah {saying} in the name of Rav: They disagree if it is four wide? Therefore if they have been polished for implements everybody agrees that it is permitted. Since Rebbi Jeremiah said in the name of Rav, if he used steps of ladders for roofing it is disqualified¹⁴⁴Wooden ladders are implements and as such subject to impurity. Steps are shaped at the ends; while they have no concavity which would make them susceptible to impurity, they are implements not to be used., and they are saying that he ruled according to Rebbi Meïr, this implies that both cases are the same¹⁶⁶Since Rav stated that planks four {hand-breadths} wide are disqualified but also that non-concave wooden parts turned into parts of implements do disqualify, for him both his and R. Joḥanan’s statements are operative.. Since Rebbi Yasa said in the name of Rebbi Joḥanan: They disagree if they have been polished for implements, therefore if it is four {hand-breadths} wide everybody agrees that it is forbidden. Now Rebbi Yasa ruled at the big assembly that one may use a cross-beam¹⁶⁷Greek μέλαθρον, τό, a substantial load-bearing beam, not simply a thin plank. Cf. Eruvin Chapter 1, Note 41. for the thatched roof, and they said that he ruled following Rebbi Jehudah, this implies that both cases are the same¹⁶⁸Since the beam need not be polished, the ruling cannot be based on his statement in the name of R. Joḥanan. He also admits Rav’s description of the description of the disagreement between RR. Jehudah and Meïr..

Samuel said, this¹⁶⁹The last statement in the Mishnah, that one may not sleep under a plank four hand-breadths wide. Babli 15a. you only are saying lengthwise; but crosswise it is qualified. Rebbi Joḥanan and Rebbi Simeon ben Laqish both are saying, both lengthwise and crosswise are qualified¹⁷⁰If the plank is on the side along a wall it becomes part of the walls, not of the roofing. But if it lies crosswise it is disqualified roofing. If on both sides there is qualified roofing of more than 4 hand-breadths, the 4 hand-breadths wide plank is disregarded and the entire roofing is qualified. The last sentence of the Mishnah is undisputed.. Rebbi Zeriqan in the name of Rav Hamnuna: Following the words of him who disqualifies here it disqualifies there¹⁷¹In his opinion, the last sentence of the Mishnah follows R. Jehudah and is denied by R. Meïr.. Rebbi Abbin and Rebbi Abun asked before Rebbi Ze`ira: Why are Rebbi Joḥanan and Rebbi Simeon ben Laqish both saying? He told them, because disqualified roofing disqualifies only in four cubits¹⁷²In the Babli 17b this is Rav’s opinion, disputed by Samuel.. A baraita disagrees with Rav Hamnuna: A sukkah which only contains his head, most of his body, and his table. If he brought a plank and added from it three hand-breadths. If you would say crosswise, this is impossible since Rebbi Zeriqan said in the name of Rav Hamnuna: Following the words of him who disqualifies here it disqualifies there¹⁷³Even if only 3 hand-breadths were used, the plank is four wide and therefore disqualified.. So we have to hold lengthwise, but it is impossible¹⁷⁴The usual Yerushalmi meaning of איפשר. Since in such a minimal sukkah it is impossible to lie down without part of one’s body being under the plank. not to sleep under it.