Q. (See the 2 prior questions 2874-75). If the tefach spread is under the extended roof, (soffit) does it count?
A. As mentioned on the questions above, Shulchan Aruch (O.H. 315: 2) rules that if the shlack cover was extended over a tefach before Shabbos began, it is permitted to continue extending it.
The schach under the soffit or overhang (the underside of eaves, that connect the wall of the house to the projecting edge of the roof, and is usually about 18 t0 24 inches wide), is considered as being under a roof, and therefore pasul and one may not seat under it.
We usually say that the Halacha of ‘dofen akuma’ applies to that underside, as we consider the walls of the house to be curved and reaching the uncovered kosher schach, up to four amos. (Shulchan Aruch O.H. 632:1).
Horav Shlomo Miller’s Shlit’a opinion is that if the tefach spread of the plastic roll lays under that overhang it still counts and the shlack could be spread.
Rabbi A. Bartfeld as advised by Horav Shlomo and Horav Aharon Miller Shlit’a