I have a 1/2 bath that is roughed in. I would like to add a shower. I am not sure where the drain from the shower needs to tie in. Would it be the toilet rough in or the sink rough in. I know this involves breaking out the concrete, centering the shower drain to the walls. Also 1/4" per foot to drain properly. Would I need a pea trap for the shower? Any help I could get with project would be greatly appreciated.
Thanks.

