Points of Caution Regarding Sechach
Supplementing with Invalid Sechach
Question: Is there any way to supplement a sukkah with invalid sechach?
Discussion: There are ways of doing so. The matter is discussed at length in Chapter 632. These halachos are complex, and one who needs to do so but lacks thorough familiarity with the subject must consult a competent halachic authority.
Points of Caution Regarding the More Common Types of Sechach
Sukkah Mats
A premade sukkah mat should feature a reliable rabbinic certification to ensure that the materials from which it was made are indeed valid for sechach and that it was manufactured for the right purposes (see above, at footnotes 33-35).
A point of caution: These mats are especially vulnerable to the wind. Thus, one must take care to tie the mats down securely so that they will not blow off. This is more than just a practical concern; it is a matter of the sukkah’s inherent validity, as sechach that cannot withstand a common wind is invalid from the outset.30
Ideally, the mat should be tied down with something that is itself valid sechach. One option is to use cords of natural fibers. Another is to place heavy wooden beams on the sechach to weigh it down.31
Another point: In the event of strong winds, the mats will often flap about. When this occurs, two points must be considered: First, have the cords tying down the sechach loosened, or has the beam fallen off to the extent that the sechach cannot now withstand a common wind? This should be checked, since if the sechach has indeed become loose, it can invalidate the sukkah, as above.32
Second, since the sechach had lifted off the sukkah and then settled back down, is it considered as though the sukkah got covered by itself, rather than for the purpose of shade?33 We will address a few of the more common scenarios:
If the sechach lifted straight up and settled back down while covering the same surface area all throughout, the sukkah remains valid.34
If part of the mat folds backwards, exposing part of the sukkah, and then flips back into place, the sukkah remains valid. Before it flips back into place, one may sit under the area that remains covered by the folded sechach, provided that that area on its own meets the requirements of a sukkah.35
If the sechach flipped off entirely and then flipped back on, it is invalid.
Some Poskim36 warn that sukkah mats are often infested, and there is cause for concern that insects will fall from the sechach into one’s food. It is therefore suggested that when storing the sechach, one should:
- Wait for it to completely dry before storing it.
- Spray it with bug-repellant.
- Store it with mothballs.
- Store it in an airtight wrapping.
- Store it in a dry place.
In general, it is important to be mindful of insects when eating in the sukkah, especially at night, when insects are attracted to the light.37
Note: although stars cannot generally be seen through the mats at night, holes can be seen in them during the day. Mishnah Berurah seems to consider this sufficient for the optimum sukkah (see above).
Bamboo and Wooden Slats38
An issue to be mindful of when using bamboo or wooden slats — which are typically laid in one direction with each piece spanning the sukkah from end to end — is not to leave too wide of an open space spanning the sukkah from end to end. Although open space does not invalidate a sukkah at less than three tefachim (24 cm) wide, one may not sleep or eat under it if it spans the entirety of the sukkah, or if the majority of one’s head39 or body fits underneath it.
Large Palm Leaves
One point to be mindful of when using this sort of sechach is that the makeup of these leaves can make it difficult to ascertain whether there is more shade than sun. Therefore, one should make sure not to merely cover the sukkah with a basic layer of leaves, but to cover the sukkah amply to ensure that there is in fact more sechach than airspace. Additionally, one must ensure that there is no seven by seven tefach (56 by 56 cm40) area that has more airspace than shade.41
30. Shulchan Aruch, 628:2. Note: this invalidation applies only if the sechach cannot withstand a common wind of dry land. Nevertheless, it is advisable to secure the sechach such that it can withstand even stronger winds, since it is difficult to provide a clear parameter of a “common wind.”
Note, also, that, for the same reason, if the only sukkah available is covered with a mat that is not tied down, one should sit in it without a berachah even if it seems incapable of withstanding common winds, since it is difficult to precisely define the common winds that the sechach must resist and, also, the ability of a particular set of sechach to withstand that wind; see Shalmei Todah (Felman), p. 336.
31. See above footnote 32.
32. However, even if it appears that the sechach has become loose, if that is the only sukkah available, one should sit in it nevertheless; see footnote 56.
33. See Shulchan Aruch 635:1.
34. Shevet HaLevi X:100 [Note: Shoneh Halachos with Toras Hamo’adim II, p. 80, cites R’ Mendel Lubin as ruling that even in this case the sukkah is invalidated.
35. Shevet HaLevi (X:100) rules that as long as part of the sechach still remains in the place where it was put up for shade, the entirety retains the status of sechach put up for shade (see Tosafos, Sukkah 19a, ד”ה לבראי). This is also the opinion of R’ Chaim Kanievsky (Shoneh Halachos with Toras Hamo’adim, ibid.).
36. Bedikas Hamazon Kehilchaso (Hebrew version, III, p. 784). See there for directives as to checking and fumigating it.
37. See Bedikas Hamazon Kehilchaso (Hebrew version, I Mevo, 8:4, p. 79).
38. Shulchan Aruch (629:18) rules that it is customary to refrain from using slats of any size as sechach. The Poskim offer two reasons for this tradition. Shulchan Aruch himself states that this is a custom that was initiated due to concern that if slats are used, they might be set up in a way that does not allow rain to get in. Others (see Mishnah Berurah 629:49) maintain that it is actually included in the rabbinic invalidation of anything that would be used for permanent roofing (referred to as gezeiras tikrah).
Nevertheless, thin wooden slats are very commonly used as sechach. The Poskim defend the practice by suggesting various explanations as to why the aforementioned reasons for the custom do not apply to these slats. Regarding the first reason, the Steipler explained that the custom is in effect only in areas where they did traditionally refrain from using such slats. However, in places where such slats are commonly used, Shulchan Aruch would agree that is permitted (See Orchos Rabbeinu II, p. 218) Indeed, this was common practice in Yerushalayim (see Salmas Chaim 341 – 349, Halichos Shlomo 8:3:3, footnote 6).
Regarding the second reason, Chut Shani (p. 215) and Halichos Shlomo state that although the slats used for sechach today are used in construction, they are not used for roofing (but, rather, for other building purposes). Therefore, the ruling of Shulchan Aruch does not apply.
Note: Halichos Shlomo requires that the slats be less than a tefach (8 cm) wide. The standard slats used for sechach usually meet this requirement.
39. Chazon Ish (144:4) clarifies that the intent is not that it is unequivocally forbidden to sleep under a gap of minimal width that runs across the entire sukkah. Rather, as long as the majority of one’s body is on one of the two sides of the gap, it is acceptable to sleep there. It is forbidden only if sleeping under the gap causes a situation where the sechach on each side of the gap covers only a minority of his body. For further discussion, see footnote d to 632:2.
40. This follows R’ Chaim Na’eh’s measurement of a tefach, which is the more stringent view in this case.
41. See Rema 631:2.