1,191. Using the Wood from a Succah

Hilchos Shofar, Succah v’Lulav 6:14

After eating on the eighth day, one removes his utensils and returns them to the house. If a person has nowhere to put his utensils (and must therefore continue eating in the succah), then if his succah is small, he should bring in his candelabra. If it is large, he should bring in his pots, pans, etc. to signify that the succah is no longer valid and the mitzvah has been completed. Since the ninth day is yom tov, one is not permitted to reduce the size of the succah in order to invalidate it.

Hilchos Shofar, Succah v’Lulav 6:15

If one did not build construct a succah, whether he neglected to do so intentionally or unintentionally, he should assemble one on chol hamoed. He should even put up a succah in the last moments of the seventh day because the mitzvah lasts until the end of the seventh day. Wood that was used to build a succah is prohibited for other purposes all eight days of the holiday. This applies to both wood used for the walls and wood used as schach. For all eight days, one may not derive benefit from this wood for any other purpose. This wood is prohibited for use on the eighth day (which is Shemini Atzeres and no longer Succos) because the succah was muktzeh for the entirety of the seventh day, including during the twilight period (which is doubtful whether is belongs to the day that is ending or the day that is starting). Since it was muktzeh during the twilight period, it continues to be muktzeh on the entirety of the subsequent day.