A sukka does not need to be made for the sake of the mitzva. As long as the schach is put on for temporary shade it is kashera. But if you put on the schach in order to block someone’s view from above, or even for shelter – but to live underneath all the time – it’s not a sukka.(ShA 1- MB1)
Even if a goy puts on the schach and his intention was to shelter cows, it is meant for shade and therefore kashera. (ShA 1 – MB 2)
The schach must be put over a space that is considered an ohel. An ohel, by definition must have walls at least one tefach high. Therefore, do not put the schach upon a frame without walls. You must have walls first, hanging down from the frame at least a tefach next to the top.Then you can put on the schach and afterwards complete the walls to the 10 tefach requirement.(Rama 1 – MB 11)
Many poskim maintain that if you put on the schach before any walls, the sukka is disqualified.(MB 10)
