Canvas Sukkah

It used to be quite popular to use a canvas sukkah although with the recent advent of sukkahs that are easier to put together, such as the modular sukkah and the ease lock sukkah, they are becoming less common. However, the concept of a canvas sukkah is actually centuries old and is specifically mentioned in the Shulchan Arukh (Orach Chaim 630:10) as being forbidden. This raises the question of how so many people could have used canvas sukkahs. There are two potential problems with a canvas sukkah.

I. Becoming Untied

The medieval sukkah under discussion was made of flax. (I don't think I've ever seen flax but I presume that those who sleep in a flax sukkah do not bring in their linens.) The problem raised by rishonim was that the flax walls sometimes became untied and could be carried away by a strong wind. Because of this, they forbade using flax walls for a sukkah, and that is recorded in Shulchan Arukh (ibid.).

The Piskei Teshuvos (630:9) quotes R. Yosef Chaim Sonnenfeld (Salmas Chaim 253), Kinyan Torah (4:70) and R. Menasheh Klein (Mishneh Halakhos 5:77) as ruling that if one ties the canvas on all sides to the frame then one need not be concerned of it being blown away. R. Moshe Sternbuch (Mo'adim U-Zemanim 1:84) and R. Moshe Feinstein (Iggeros Moshe, Orach Chaim 5:40:2) also raise this possibility but rule strictly on this.

II. Moving Walls

The Gemara (Sukkah 23a) states that a wall that cannot withstand a regular wind is not strong enough considered a wall. Therefore, if you build a large house of cards you cannot use that as one of the walls for your sukkah because it will almost certainly fall down under ordinary circumstances. However, the Gemara does not define what exactly it means for a wall not to be able to withstand a regular wind. Does it mean that the wall will be moved by the wind or fall down because of the wind? This has practical ramifications regarding a canvas sukkah because canvas walls sway in the wind.

The Chazon Ish (Orach Chaim 77:6) rules that as long as a regular wind does not move the wall so much that it becomes invalid (e.g. falls down or is moved so far from the sekhakh or the ground that the wall is invalid) then it is kosher. Therefore, this rule is not of concern to canvas walls. R. Yitzchak Isaac Liebes (Beis Avi 4:73:17) agrees with the Chazon Ish and specifically permits a canvas sukkah.

Most others, however, are stricter. R. Shlomo Zalman Auerbach (Halikhos Shlomo, Mo'adim vol. 2 7:1) rules that if the wind moves the wall even a little bit then the wall is invalid. R. Ovadiah Yosef (Yechaveh Da'as 3:46; Yabi'a Omer, vol. 9 Orach Chaim 59:A) rules likewise. I recall hearing from R. Hershel Schachter, although I cannot find it in my notes, that there are two other positions -- that if the wind moves the wall more than 1 tefach (appr. 3 inches) or 3 tefachim (appr. 10 inches) then the wall is invalid, but otherwise not (I think the latter was attributed to R. Ya'akov Kamenetskt but I could not find it in Emes Le-Ya'akov, perhaps I remember incorrectly).

III. Conclusion

There is a lenient view on a canvas sukkah and it seems to be a widespread custom to rely on this leniency. My personal policy is that I will not use one but if I am invited to the house of someone who uses one, I will be lenient and eat in it.

(See also this excellent article on the topic: link)