Siman - Succah Daf 16

  • החוטט בגדיש אם יש שם חלל טפח במשך שבעה

The Mishnah on Daf 15a stated, החוטט בגדיש לעשות לו סוכה אינה סוכה – If one hollowed out a haystack to make a succah, the succah is passul. On our Daf, Rav Huna says: לא שנו אלא שאין שם חלל טפח במשך שבעה – They taught this halachah only regarding a case where there was no cavity inside the haystack one tefach high, for a length of seven tefachim. If there was a cavity one tefach high, for a length of seven tefachim, then it is a kosher succah. Rashi explains that for the straw to meet the definition of s’chach, it would have to cover an empty space of at least one tefach high, for that is the minimum height of an ohel. Therefore, if it is also has a length of seven tefachim, It would meet the requirement of kosher s’chach, and there would not be an issue of תעשה ולא מן העשוי. Although the cavity needs to be hollowed out further to a height of ten tefachim, that is necessary only in order that to make the walls kosher, and the requirement of תעשה ולא מן העשוי does not apply to succah walls.

  • מחיצה תלויה מתרת

In the next Mishnah, Rebbe Yose disagrees with the Tanna Kamma who holds that if one constructs succah walls from the top down, then if a wall is three tefachim above the ground, it is passul. Rebbe Yose says: כשם שמלמטה למעלה עשרה טפחים כך מלמעלה למטה עשרה טפחים – Just as a wall built from the bottom up, is kosher if it is ten tefachim, so too a wall built from the top down, is kosher. provided it is ten tefachim high, regardless of the gap between it and the ground. The Gemara explains that Rebbe Yose maintains thatמחיצה תלויה מתרת  – a suspended partition is a kosher mechitzah.

The Gemara brings a Mishnah from Eruvin, where Rebbe Yehudah rules that in a case of a cistern between two chatzeiros, the wall running over the cistern should act as a mechitzah to legally divide the water, even if it does not enter the cistern’s cavity. Rabbah bar bar Chanah said in the name of Rebbe Yochanan that Rebbe Yehudah’s ruling is in accordance with the opinion of Rebbe Yose who holds, מחיצה תלויה מתרת in the case of the succah walls, and so too here, the wall going over the cistern, which is a מחיצה תלויה, is considered a full wall. The Gemara rejects this suggestion, pointing out that perhaps Rebbe Yehudah would only apply the principle to a d’Rabbanon, such as eruvin, but not to a d’Oraysa, such as a succah, and perhaps Rebbe Yose would only apply it to a succah, which is an איסור עשה, but not to a matter of Shabbos, which is an איסור סקילה.

  • Lavud can be applied twice to the same mechitzah

Rav Chisda said in the name of Avimi: מחצלת ארבעה ומשהו מתרת בסוכה משום דופן – A mat whose width is four tefachim and a bit, is a kosher wall for a succah. What does one do to render it a kosher wall? One suspends it midway between the s’chach and the ground, with a gap of less than three tefachim below it, and a gap of less than three tefachim above it, וכל פחות משלשה כלבוד דמי – And it is a kosher wall because any gap less than three tefachim wide, is treated as though it were closed, based on lavud. The Gemara explains that one might have thought, חד לבוד אמרינן תרי לבוד לא אמרינן קא משמע לן – that we apply the law of lavud to extend a mechitzah once, but not to apply lavud to extend it twice. Rav Chisda therefore teaches that we apply lavud twice to the same mechitzah.