I am converting a tub to a shower. I took out the tub and found the from the tee connecting the overflow to the old tub drain, there is just horizontal pipe. From the tee, it’s 24″ straight down until I hit anything! I checked my other shower and it’s 24″ straight down, with mighty echo when water goes down. Does this mean I’m missing traps, and should one be added for the “new” shower? Do I need to cut out more slab than the existing 5×13 opening to make room for the plumber?