Building a bathroom without bathroom rough in is certainly not a good thing. Rough in for bathroom is actually something quite important because it has function to show you about the very basic design of your bathroom in which plumbing system is also included. Because the function is quite important, it is so sure that the rough in plan should really be made carefully. If needed or if you cannot create the plan on your own, you can just hire a professional service for that. It would be better if the service is taken from the same contractor that you hire to build the bathroom for you because everything can be done much easier.