The maximum space from the floor of the sukka till the schach is 20 amos.Within this height the walls are able to be built out of flimsy material.You are allowed to build the walls out of sturdy material as long as you could build it out of flimsy material.Higher than 20 necessitates sturdy material – contravening the requirement of diras arai.(ShA 1- MB3)
”Diras arai” calls for schach that is really arai. Therefore you aren’t allowed to nail down the schach. (ShaH 6)
You can minimize the space of a high sukka by building a seven-tefach platform against three of the walls.The sukka is kasher on top of the platform. Even off of the platform is a kasher extension. (ShA 5 – MB18)
You aren’t allowed to make any adjustment which kashers the sukka on Yom Tov. It’s a form of tikkun. (MB 13)
The minimum space from the floor till the schach is 10 tefachim (80 cm). Make sure no leaves hang down within 10. Although you can hang noi sukka from the schach – it won’t minimize the shiur.(ShA 8,9 – MB 25)
