http://revach.net/article.php?id=2854

Section: Halacha   Category: Tshuvos
Rav Shlomo Zalman Auerbach: Can You Build Your Succah On Friday After Chatzos?
The Rema writes (OC 625:1) that you should build your Succah immediately after Yom Kippur.  The Mishna Brura (2) says that this means starting to build it.  If possible you should complete it the next day. 

If Yom Kippur is Thursday and the day after is Erev Shabbos, then you should try to finish it by Chatzos.  After Chatzos, says the Mishna Brura, the Pri Megadim says it is assur to build.  The Bikurei Yaakov says that you may build it until Mincha Ketana, which is 3 hours (Sha'os Zemaniyos) after Chatzos.

Rav Shlomo Zalman Auerbach (Halichos Shlomo 2:7:13) was asked if someone is building a Succah before Chatzos may he continue to build after Chatzos and he said that they may.

Important Note: We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. Please also understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.

This article has not been reviewed by the posek of the AskRevach section, Rav Peretz Moncharsh.  Any questions regarding this topic and Halacha L’Maaseh may be asked to him at www.revach.net/ask