Q. (See the 3 prior questions; 2674-76). Can one just cover the suka with a plastic tarp or canvas that rests directly on the scahch to protect it from rain?
A. Igrois Moshe (O.H. 5: 39: 4) indeed permits to spread directly on the schach a plastic sheet resting directly on the schach, without any air space between them.
His reason is that since it is only placed temporarily and will be removed after the rain stops, as he needs the suka and does not in principle want that cover, besides there is no tefach space underneath it. Therefore there is no ohel created and no boneh prohibition involved
Horav Shlomo Miller’s Shlit’a opinion is similar.
Rabbi A. Bartfeld as advised by Horav Shlomo and Horav Aharon Miller Shlit’a