I just finished building a tornado shelter in the bedroom. I poured a 5" concrete slab with re-bar for the roof. The roof is 35" x 47" The form is 2 pieces of 3/4 osb with plastic on top held up all around the edges with block and 2 4x4 posts to prevent sagging. This was done last Sunday 1/29
Does anyone have an idea how long I have to wait until I can remove the 2 supports?