Sukkah 4a
סוכה ד׳ א — ד"ה הָיְתָה גְּבוֹהָה מֵעֶשְׂרִים אַמָּה וּבָנָה בָּהּ
Sukkah 4a:8
The Gemara derives the law of דופן עקומה and discusses the maximum width of invalid roofing that may be absorbed into the bent-wall principle. This is the Talmudic basis for the practical ruling in Orach Chayim 632.
הָיְתָה גְּבוֹהָה מֵעֶשְׂרִים אַמָּה וּבָנָה בָּהּ אִיצְטְבָא כְּנֶגֶד דּוֹפֶן הָאֶמְצָעִי, עַל פְּנֵי כּוּלָּהּ וְיֵשׁ בָּהּ הֶכְשֵׁר סוּכָּה — כְּשֵׁרָה. וּמִן הַצַּד, אִם יֵשׁ מִשְּׂפַת אִיצְטְבָא לַכּוֹתֶל אַרְבַּע אַמּוֹת — פְּסוּלָה, פָּחוֹת מֵאַרְבַּע אַמּוֹת — כְּשֵׁרָה. מַהוּ דְּתֵימָא: הָתָם הוּא דְּחַזְיָא לְדוֹפֶן, אֲבָל הָכָא, דְּלָא חַזְיָא לְדוֹפֶן — אֵימָא לָא, קָא מַשְׁמַע לַן.
If a sukka was more than twenty cubits high and one built a raised platform in it opposite the entire middle wall, as typically a sukka has three walls and the fourth side is open as an entrance, and the platform has an area of at least a bit more than seven by seven handbreadths, the minimum area required for fitness of a sukka, the sukka is fit. Since the seven-by-seven-handbreadth section from the platform to the roof has three walls and it is less than twenty cubits high, that section is a fit sukka in and of itself, and the rest of the sukka beyond the platform is fit as far as the roofing continues. And if one built the platform along the side wall of the sukka, then the following distinction applies: If there are four or more cubits from the edge of the platform to the opposite wall, the sukka is unfit, as the area of the platform has only two walls. However, if the distance to the opposite wall is less than four cubits, the sukka is fit, as the halakhic status of the roofing that covers the distance to the wall is that of a curved extension of the opposite wall. The Gemara explains that there is indeed a novel element to the halakha of the platform. Lest you say that one applies the halakha of a curved wall specifically there, in the case of a house that was breached, as the wall of the house is suited to be the wall of a sukka since it is less than twenty cubits high; however, here, in the case of the platform, where the opposite wall is not suited to be the wall of a sukka due to its excessive height, say no, the halakha of a curved wall does not apply. Therefore, it teaches us that in the case of the platform too, the roof is considered an extension of the wall.
