Q: I have been invited to eat out on Succos. The Succah has canvas walls which shake in the wind. Is this a problem?
A: The Mishna1 states that a person can use the trunks of trees as a succah wall. This Mishna is referring to a scenario where the tree trunks are very close to one another, or the space between them has been filled with some other material, and the overhang of the tree branches will not invalidate the s’chach. The Gemara2 states that this is true only if the tree trunks do not sway. If the tree trunks are supple and sway in a normal wind, the succah wall is not valid. The Shulchan Aruch3 codifies this halacha, and adds that if the tree trunks are supple one can tie them to each other in such a manner that they will no longer sway in the wind. However, he states that it is not ideal to do so, as it is possible that the ties will loosen on Yom Tov,rendering the succah invalid.
How rigid do the succah walls need to be? The Chazon Ish4 suggests that a wall formed from tree trunks is invalid only if the trunks will sway more than three tefachim away from each other, or if the top of the wall will sway more than three tefachim away from the s’chach. There is a general principle in halacha called lavud, which means that any gap of three tefachim or less is not halachically significant and can be considered as filled. Therefore, if the top of the wall is within three tefachim of the s’chach we would consider those three tefachim as filled by s’chach, thereby reaching the top of the wall. However, if the top of the wall sways more than three tefachim, one could not consider the wall to be connected to the s’chach. According to the Chazon Ish, three tefachim is approximately 11½ inches.5
There is another principle in Hilchos Succah known as gud asik mechitzos.6 This means that if a wall of a succah is halachically kosher, we would consider that wall to extend vertically for any distance. If the wall of a succah is ten tefachim high, which is the minimum height requirement for a succah wall,7 we consider that wall to extend upward towards the sky. Therefore, if a succah wall is ten tefachim high, the vertical distance between the top of the wall and the s’chach is immaterial, as long as the horizontal distance between the edge of the s’chach and the top of the wall is three tefachim or less. It would therefore follow that, according to the Chazon Ish, if at the height of ten tefachim the tree trunks are rigid enough that they do not sway more than three tefachim, the succah wall is kosher.
Furthermore, it would seem that, according to the Chazon Ish, if a canvas wall was tied at the top and bottom, so that the bottom was always vertically within three tefachim of the ground and the top was always horizontally within three tefachim of the s’chach, the wall would be kosher even if the middle of the canvas moved in the wind. However, the Igros Moshe8 states that that no part of the canvas should sway more than three tefachim to each side in a regular wind, including the middle of the canvas.
The canvas succahs that are commonly used nowadays are tied at the top and bottom and do not sway more than three tefachim in the wind; therefore, such a succah would be kosher. However, as mentioned above, the Shulchan Aruch states that it is not ideal to use such a succah due to the concern that the ties might become loose. Therefore, the Igros Moshe says that such a succah should ideally be used only if the canvas would not sway more than three tefachim without the ties. It seems that the Igros Moshe would accept lechatchila a canvas wall, if the canvas has been sewn around a metal frame in such a manner that no part of the canvas sways more than three tefachim from the frame in a normal wind.
The Moadim Uzmanim9 suggests that nowadays, where the canvas succahs are very well attached, the concern of the Shulchan Aruch that the ties may become loose no longer applies; however, he concludes that it is advisable not to rely on this. He also questions the ruling of the Chazon Ish that the wall is kosher if it sways less than three tefachim from the schach. Rav Shlomo Zalman Auerbach zt”l10 and Rav Ovadiah Yosef shlit”a11 also pasken that the wall should not sway at all. The Mishneh Halachos12 points out that it is a commonly accepted custom to use canvas succahs. He suggests that the concern of the Shulchan Aruch that the ties will loosen is limited to a scenario where the tree trunks are tied only to each other, with no further structure supporting the wall. However, if a person constructs a square frame and securely ties the canvas to it, the resulting wall is kosher lechatchila.
The Mishneh Halachos quotes the Gaon MiTchebin as advising a person with a canvas succah wall to do the following: Tie a taut string from one edge of the canvas to the other, parallel to the ground and within three tefachim of the ground. Tie a second taut string likewise, above and within three tefachim of the first string. Tie a third string likewise, above and within three tefachim of the second string, and a fourth string above and within three tefachim of the first string. The strings should be distanced from each other so that the fourth string is more than ten tefachim above the ground. As the distance between each string is less than three tefachim, the rule of lavud allows us to consider the space as filled, thereby creating a wall with a height of ten tefachim. As the strings are taut and do not move in the wind, the Shulchan Aruch’s concern that the ties may loosen does not apply, and the resulting wall is kosher lechatchila.
According to Rabbi Heinemann shlit”a, lechatchila one should follow the psak of the Igros Moshe that no part of the canvas wall should sway more than three tefachim. Bedieved, one may use a succah if the canvas wall is tied at the top and bottom, in accordance with the ruling of the Chazon Ish.13
Halachic queries regarding all topics may be presented to The Institute of Halacha at the Star-K by calling 410-484-4110.
1.סוכה פ”ב משנה ד
2.סוכה דף כד ע”ב
3.שו”ע או”ח סי’ תרל סעי’ י
4.חזון איש או”ח סי’ עז (יג) ס”ק ו
5.עי’ בשיעורין של תורה עמ’ סד שג’ טפחים הוא 30 צ”מ ולכה”פ 29 צ”מ, דהיינו 11.4-11.8 אינצ’ים
6.עי’ מ”ב סי’ תרל ס”ק מד
7.שו”ע סי’ תרל סעי’ ט
8.שו”ת אגרות משה או”ח ח”ה סי’ מ אות ב
9.מועדים וזמנים ח”א סי’ פד
10.הליכות שלמה מועדים ח”ב פ”ז אות א
11.שו”ת יחוה דעת ח”ג סי’ מו ושו”ת יביע אומר ח”ט או”ח סי’ נט אות א, והביא שם שכ”כ הגר”י מקרלין בקהלת יעקב סוכה דף כד ע”ב ובשו”ת משכנות יעקב או”ח סי’ קכג
12.שו”ת משנה הלכות ח”ה סי’ עז
13.שמעתי ממו”ר ר’ היינעמאן שליט”א