Q. It says that one should begin putting up the Suka on the night at the end of Yom Kippur and then finish it on Friday. Can one do fixing of the Suka Erev Shabbat after Chatzos (midday)?
A. Mishna Berura (626: 2) quoting P’ri Megadim rules that on Erev Shabbos one should only work on the Suka until a half hour after Chatzos.
However, Shulchan Aruch (O.H. 251: 1) mentions two opinions, and the second one maintains that one can do regular work on Erev Shabbos until Mincha Ketana and that is about three and a half hours (Zemanios) after Chatzos or around three thirty in a day of twelve hours. Mishna Berura there (ibid. 3) rules that one can be lenient.
Bikurei Yaakov (5) quotes a list of Poskim that support that view. They recommend that one should have already ended by then all the Shabbos preparations.
Horav Shlomo Miller’s Shlit’a opinion is that one can certainly be lenient regarding the great mitzva of building a Suka.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a