When building a new home or adding another bathroom you will hear the term ‘rough in’. This is simply the building of the new plumbing system inside the stud walls as they are built. Electricians and plumbers usually work together to do rough ins. The plumber will put in the waste pipes, then he will plug the ends of each pipe at the place they will connect with the fixtures. The plumber will be aware of the correct size of pipes needed for each place, as well as the sizes of standard fixtures so the walls and pipes can be installed in the correct place. Before you begin be sure to get a permit. The addition will have to be inspected before incoming water can be turned on. This should be no problem for an experienced plumber who knows the codes.