The Mitzvah to Beautify the Sukkah
It is a great Mitzvah to beautify the Sukkah and decorate it as much as possible by adorning it with beautiful vessels and illuminating it with fine lights. The Mekubalim write that by honoring the Sukkah with fine lighting, one’s soul will merit resting peacefully in Gan Eden; one’s performance of this Mitzvah with pure intention and in a beautiful manner will directly impact the kind of Sukkah that will be made for one’s soul in Gan Eden, as the holy Zohar (Parashat Pinchas) states. When one places his fine vessels and linens in the Sukkah in order to adorn it, Hashem shall prepare the individual several canopies in the celestial Gan Eden. Nevertheless, we must point out that sometimes as a result of one’s good intention to decorate the Sukkah, one may inadvertently invalidate the Sukkah. One must therefore be fluent in the laws discussed in this segment in order to know how to observe this Mitzvah according to Halacha.
Conditions for Valid Sechach
The Torah states (Devarim 16): “You shall make for yourself a holiday of Sukkot when you gather [the produce] from your granaries and wineries.” Our Sages learned from here (Sukkah 12a) that one should make the Sechach out of things gathered from granaries and wineries, i.e. the waste from granaries and wineries, such as straw, hay, twigs, or empty clusters of grapes and the like.
Similarly, the book of Nechemia (Chapter 8) states that the leaders of the nation told the Jewish people: “Go out to the mountain and bring olive branches, branches of an oily tree, myrtle branches, palm branches, and branches of a thick tree in order to make Sukkot as it is written.” Our Sages learned from here that in order to be valid, the Sechach must meet three requirements:
It must grow from the ground, it must be detached from the ground, and it must be something that is incapable of becoming impure (as we have already discussed), similar to the waste of granaries and wineries which grows from the ground, is detached from the ground, and is not capable of becoming impure, for anything which is neither a vessel or a food is incapable of becoming impure. If, for instance, a corpse would come in contact with a palm branch, the palm branch would not become impure. However, if it would come in contact with a wooden vessel, it would become impure, and it is thus invalid for use as Sechach (even if the vessel has broken, one may still not use the broken pieces as Sechach).
Thus, one may not use any type of metal as Sechach, as metal does not grow from the ground. Similarly, one may not use tree branches that are attached to the ground, for only things that are detached from the ground may be used as Sechach. Additionally, one may not use foods or vessels (even if they are made from wood) as Sechach, for these things are capable of becoming impure. Even if one covers his Sukkah with valid Sechach and only places invalid Sechach on top of that, the Sukkah is invalid. Therefore, if one builds a valid Sukkah but it is under a neighbor’s balcony, the Sukkah is most certainly invalid.
Paper Decorations
Paper may not be used as Sechach although it is a derivative of wood, since its appearance has changed completely and it is no longer considered something that grew from the ground. Thus, decorations hung from the Sechach in order to beautify the Sukkah can very well invalidate the Sukkah, for they are invalid for use as Sechach.
Therefore, Maran Rabbeinu Ovadia Yosef zt”l writes that one should take care to hang such decoration within four Tefachim (approximately thirty-two centimeters) of the Sechach, for in this way, they are considered part of the Sechach and they in no way invalidate the Sukkah, even if they are quite large. However, if the decorations droop below four Tefachim of the Sechach, there is concern for the invalidation of the Sukkah, as we have explained.
Summary: For the Sechach (roof) of the Sukkah, one must use a material which grows from the ground, is no longer attached to the ground, and which is incapable of becoming impure. If one wishes to adorn one’s Sukkah with paper decorations (or any other material for that matter), one may do so but one must make sure that they are hung in close proximity to the Sechach and do not droop down more than thirty-two centimeters (12.6 inches) from the Sechach, for this invalidates the Sukkah.