1,172. The Requirements of Schach

Hilchos Shofar, Succah v’Lulav 5:1

Not every material may be used for schach (the roof of a succah). Schach must be made from something that grows from the ground, has been detached from the ground, is not susceptible to ritual impurity, does not have an offensive odor, and does not have pieces that will regularly fall off and wither.

Hilchos Shofar, Succah v’Lulav 5:2

If a person uses for schach something that does not grow from the ground, or is still connected to the ground, or is susceptible to ritual impurity, it is invalid. If he used schach that has pieces that fall off and wither, or that has an offensive odor, he has acted improperly but it is valid. The Sages only said not to use these out of concern that one would choose to leave his succah because of them. One must ensure that the schach’s branches and leaves do not dip within ten handbreadths of the ground (about 30”), so that a person using the succah will not be uncomfortable. Metal, bones and hides are unacceptable for use as schach because they don’t grow from the ground. If one draped vines and such over the top, it is invalid because they have not been detached. If one used wooden utensils, mats that were designed for lying on, and similar such things as schach, it is invalid because these things are susceptible to ritual impurity; broken and worn-out utensils are similarly unacceptable. Since these things were formerly susceptible to ritual impurity, we are concerned that one may come to use broken utensils that are still susceptible to ritual impurity.