We have the first floor plumbing draining into the main stack which drains down into the concrete of our basement and out to the street. The basement bathroom toiletsinkshower rough in drains tie into that main drain underneath the concrete. How to Install a Basement Bathroom 1. Lay out the 2x4 bottom wall plates to establish the perimeter of the bathroom walls. Measure off the wall plates to locate the center of the shower drain and toilet flange. Dig a trench extending from the existing drainpipe over to the new locations. do it yourself Basement Plumbing Basement bathroom plumbing is uniquely complex, but not so hard that you can't do it on your own. You need to understand that if your bathroom is below your sewer lines, you'll have to invest in a method to get waste water up to the sewer or to the septic tank. Feb 10, 2015Detect the cast iron pipe leading from the main waste stack to the sewer using a metal detector. This is the pipe in the ground that the new toilet and sink will flow in to. Identify where you want the sink and the toilet to be placed in the basement. Roughingin the plumbing for a basement bathroom is a big job, but the savings are huge. Adding a basement bathroom is a big, complicated project. Break through the concrete to verify that the main line is Plan the system. Aug 04, 2014The remaining tasks to finish the basement bath are: Obtain a building permit. Install a ceiling ventilation fan. Install a vent to the outside for the fan. Install the shower hot cold water supply lines. 10 Stylish Basement Laundry Rooms. When it comes to installing plumbing in a basement bathroom, there are a few options that may work for your space. If you are lucky enough to have a home that was built above the sewer lines, then you can attach the plumbing in the same manner you would if the bathroom was located above ground. Re: Venting Basement Bathroom (Rough In) Author: hj (AZ) 1. The 3 pipe should be for connecting to the toilet. If they were REALLY plumbers and they installed the rough piping, they should also have left a vent opening in the ceiling somewhere for you to connect to. A basement bathroom improves the function of your home, and it adds real estate value like few other home improvements. But adding a fullfunction basement bathroom is no easy project. Few DIYers are really able to tackle all the tasks involved, and more often than. Fill in the holes to 3 inches below the basement floor. Pour 3 inches of concrete to replace and level the floor. Now youre ready to frame the bathroom. Once framing is in place, run the vent pipes from each drain. You can join them together before tying in to an existing vent pipe.