I was in a shul where someone cleaned the shul on shabbos and they have a folding/collapsing bima. For mincha they wanted to open it up and the question came up if it’s a problem of making a ohel, especially since it was a very large one.
Does it make a difference since it’s for a dvar mitzvah? Does it make a difference that its made to open and close?
You may open or close the bima without hesitation on Shabbos. The reason for this is since it was made to open and close, it isn’t considered making an ohel. Another permitted factor here is that the bimah is not meant to cover anything, and it is made for what will be put in top of it.
The fact that it is for a mitzvah doesn’t really help us here, and the fact that it is large is not a problem, this may even be done to a collapsible chuppah.
O:CH 315-5, M:B ibid 27, Pischei Teshuvos 315-16.