In order for the s'chach to be permitted it has to meet the following conditions: it must be a material which grows from the ground, it must be detached from the ground, and it must not be susceptible to tumah (ritual impurity).2. Can you elaborate further the halachah that we are not allowed to use for s'chach materials which are susceptible to tumah?
The Shulchan Aruch mentions several examples of materials that can become tomai; metal rods, and bed frames (broken parts of the bed) even of wood. Likewise all vessels are prohibited to be used for s'chach. This halachah would apply even if the vessel was broken and no longer has the appropriate minimum measurement in order to become tomai (impure) (Shulchan Aruch, section 2).3. Is it permissible to use for s'chach materials which can become tomai (impure) only rabbinically?
We do not use for s'chach materials that are only rabbinically tomai. However, in a situation where one has no substitute we would permit him to use these materials, though no blessing should be made upon the succah (Biur Halachah).43. Can something that is still attached to the ground be used as s'chach?
One may not use anything that is attached to the ground as s'chach; such s'chach would have the same halachos as a tree. This only applies when the plant was always attached to the ground, such as a grapevine or pumpkin vine, but something that was already cut from the ground and subsequently reattached would be permitted to use as s'chach (Shulchan Aruch, section 36).44. Can materials that have a bad odor be used as s'chach?
Any plant, even if it is not fit for human consumption and thus not susceptible to tumah, which has a bad odor is prohibited rabbinically to use as s'chach. However, after the fact if it was already used as s'chach it would not have to be replaced, and it is completely permissible to sit in such a succah (Shulchan Aruch Harav, section 21).45. What would the halachah be if the odor is so bad that it is repugnant to most people?
In such a situation there are those that say the s'chach would be prohibited to use by Torah law, since we require that one's dwelling in the succah be similar to that in one's own house (and since no one would use such foul smelling materials for his house they are likewise prohibited to use in the succah) (M.B. section 38).46. Can branches whose leaves fall off be used as s'chach?
Here also the Rabbis prohibited this s'chach to be used wherever possible. This would only apply to plants whose leaves constantly fall off. However, if they only fall when a wind blows it would be kosher s'chach. The reason for this prohibition, and that of malodorous s'chach, is that the Rabbis were worried that due to the falling leaves or bad odor people would leave the succah (Shulchan Aruch, section 14; M.B., section 39).Next Chapter