Various Materials as Schach
Question: Can I simply buy wooden fencing or shades and use them for sechach?
Discussion: This is acceptable, provided that it is clear that the product was originally manufactured for these purposes and not for sitting or lying (which renders it susceptible to tumah and thus invalid for sechach). This includes that it was not manufactured in an area where such products are commonly used for sitting or lying, since it is then assumed to have been made for that purpose.7 In addition, it is only acceptable in an area8 where such a product is not commonly used for sitting or lying.9
Question: Many pergolas have slats inserted into them which cover the porch the entire year. Is it acceptable to simply make the sukkah underneath and consider these slats the sechach?
Discussion: Sechach may be left permanently over an area used as a sukkah, provided that it was originally placed there to serve as sechach.10 In addition, the slats must not be nailed or screwed in place (as above). If these conditions are met, the sukkah is valid. However, one must remove a tefach-by-tefach section (10 by 10 cm11) of the sechach, or a slat of any width that extends across the entire sukkah, and then put it back with intent for it to serve as sechach.12
Note: This is acceptable only if the walls of the sukkah are also permanent, or are in place before one removes the sechach and puts it back, because a sukkah whose sechach preceded the walls is invalid (see below).
7. Shulchan Aruch 629:6.
8. Sha’ar Hatziyun (629:35).
9. Of additional note is that if it is held together by metal wire and the like, there might be a problem of ma’amid. Note also that the purpose for which it is displayed in a store, might not be the purpose for which it was originally manufactured, especially if it was manufactured in a foreign region.
10. Note: putting it there for shade suffices as well (Mishnah Berurah 636:3), as long as it is not serving as a ceiling for one’s regular living quarters; see Shulchan Aruch 636:2.
11. This assumes the measurements of Chazon Ish, whose calculation for the length of a tefach is more stringent in this case.
12. Mishnah Berurah 636:7.