Basement Toilet

Basement Toilet - rough plumbing

If you think that roughing for a basement toilet is difficult, take heart. It is not as complicated as it appears. In fact, if you follow the steps on this page along with the diagrams that I included, you will do just fine.

Before you start to dig and putting pipes together, get familiar with some basics.

- check with your local inspector for the required codes for the job you are doing.

- pipe sizes always indicate the inside diameter of the pipe.

- for drain and vent piping, use PVC Pipe or ABS Pipe. The difference is that ABS Pipe is not as rigid as PVC Pipe.

- when cutting pipe weather plastic or copper, always ream clean the inside edge of the cut pipe to avoid restrictions.

- if you are soldering close to wood, always protect the wood from the flame of the torch with sheet metal or . (use a piece of sheet metal folded in half).

- venting is a must to relief air from drain pipes

- always vent a water fixture and add a water trap as part of the drain line.

- install a common vent between two fixtures, for example, the basement toilet and the sink to provide relief air.

- water traps hold water to create a seal against poisonous sewer gases.

- slope drain pipe runs down at 1/4inch for every foot.

- during the planning of the basement renovations try to plan the basement toilet close to the main drain line, it will save time and money.

One big advantage of having a basement toilet is that one does not have to run up stairs to use the toilet. The other advantage is that one does not have to wait if the main bathroom is occupied.

On this page I will explain one of the methods how to rough-in the plumbing for a basement toilet.

Note: all measurements are taken from the center of the pipe or fitting.

Before you start breaking the basement floor, you need to know exactly where the fixtures will be installed. This will avoid the need to relocate the piping and fittings once the walls are finished.

Toilets.

From the bottom plate or stud wall to the center of the toilet flange. There should be 12-1/2”inches (before the drywall is on the wall). If the wall is finished then measure 12” inches from the finished wall. (Make a “X” mark on the cement floor).

Note: if you are including a bath tub, remember to dig a bigger hole to receive the tub drain line and put the vent line between the bath tub drain and the basement toilet drain.

Rough-in the water-supply line for the basement toilet at 6 inches to the left and 6 inches from the floor. (mark a “X” on the wall).

Now it’s time to break the concrete basement floor. Here you want to join into the main drain line that’s going to the street.(Don’t forget the vent in-between the toilet and sink).

Start digging the floor at an area parallel with the main vertical clean-out (the nut on the side of the pipe usually points to the direction of the main drain where you will connect the vent and drain pipes).

After removing the concrete and enough dirt from the area to be cut off the drain pipe measure the distance from the center of the toilet flange to the center of the drain line and draw a line on the cement floor make a note of this measurement. Click here for diagram.

Nail a piece of 2”x4” onto the stud wall and hang a plumb-line, 12-1/2inches from the stud wall and about 1inch from the floor as a reference to the center of the toilet flange. Hang the plumb bob ta 12" from the wall if the wall is drywalled.

Break the concrete floor from the flange area to the drain lines, wide enough for the toilet drain and the vent line and to allow enough freedom to maneuver.

Fit an elbow fitting onto the flange and cut a piece of drain pipe to the measurement you took earlier from the flange to the main drain (a few inches to be cut off later).

Dry-fit the fittings and pipe and lay in the exact place where it should on the ground.Make sure the flange is centered under the plumb-bob and the “Y” fitting square under the main drain line.

Now measure from the outside of the “Y” fitting to the side of the main drain pipe. Pull the fitting and cut the difference off the drain pipe. Fit the “y” fitting back on tight and double check by laying the drain with all the fittings in place and where they should be. (Make any adjustments as needed).

When you are satisfied with the set-up and everything is even and level accordingly, with all measurements to specifications. Mark a line on the end of the fittings and a line on the pipe so that you can realign them back in place when cementing the joints back together.(If you are using black pipe stick masking tape across both ends to be cemented and mark on the masking tape).

Spread some primer on both the end of the pipe and the inside of the fittings as per instructions on the container. Cement the joints making sure that all marks line up.

Join the 2 inch in diameter vent line to the main further down from the drain pipe of the basement toilet and come out at the other end from under the bottom plate of the stud wall long enough to “T” off to the 1-1/2“ sink drain. Note: ( The height from the floor to the center of the sink drain is 18 inches). Now you can join the vent line to the vent stack.

Important NOTE: always check the diagrams before doing any work.

Fill the hole back and pack the dirt down, the more the better. Fill the rest of the dug-out with ready Crete and that’s the whole rough-in for a basement toilet.

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