Installation of a Floor Drain Design

Connection couplings join two sewer pipes together.

Sewer drains that attach to floors are used to supply toilets with a route to pass its waste to the main sewer line and then out to the city sewer or private septic tank. The first section of the sewer attaches to the floor and is called a toilet flange. This looks like a small section of pipe with a lip attached at one end which rests on the floor. A 90-degree elbow joint then connects to the flange and sewer pipe is then fitted as per the design and runs to the main sewer line.

Things You'll Need

• Tape measure
• Marker pen
• 1/2-inch wood drill bit
• Drill gun
• PVC primer
• PVC toilet flange
• PVC 90-degree elbow joint
• PVC cement
• PVC sewer pipe
• Handsaw
• PVC couplings
• Utility knife
• PVC connecting coupling
• PVC straight coupling
• 1-5/8-inch galvanized screws
• Screw gun

Instructions

1. Measure and mark on the floor the location for the sewer flange hole. The required distance from the hole to the back wall is generally found in the toilet manufacturer's installation guide. Rest the base of a PVC toilet flange (lip facing up) on the mark and run a carpenter's pencil around the base to create an outline circle on the floor. Use a 1/2-inch wood drill bit to drill around the circle.

2. Brush PVC primer around the flange's bottom inside end, as well as on the PVC 90-degree elbow joint's outside male end. Then apply PVC cement to each primed area. Push the elbow joint into the bottom of the flange and hold it in place for 10 seconds while the cement sets.

3. Lower the flange and elbow joint down into the hole. Turn the female end of the elbow joint in the direction as specified by the drain design (though usually it will face the direction of the main sewer line). Measure and cut the first section of PVC sewer pipe to length as per the design's specifications. Make a straight perpendicular cut through the pipe using a handsaw, circular saw or miter saw. Scrape off any plastic burrs from the cut using a utility knife.

4. Brush primer around one outside end of the PVC pipe, as well as the inside female end of the elbow joint. Cement both areas and push the pipe into the elbow joint. Hold in place for 10 seconds. Now measure and cut to length all sections of PVC pipe to suit the design specifications. Prime and cement them together with PVC couplings, which come in 30, 45, 60, 90 and 180-degree (straight) angles. The last section of toilet sewer pipe should fall just short of the main sewer line.

5. Mark the main sewer line at the point where the new toilet sewer line will connect to it. Make a second mark two inches along the pipe from the first mark. Make a straight cut through the pipe at both marks. Prime around both outside ends of the cut pipe, as well as both inside ends of a PVC connecting coupling. Cement all four primed areas and squeeze the coupling between the pipe ends. Point the coupling's side spout up and towards the new toilet sewer pipe and hold in place for 10 seconds.

6. Measure between the coupling's side spout and the end of the sewer pipe coming from the toilet (allow for how much the pipe will enter into the end of the spout -- usually 3/4-inch). Cut a section of sewer pipe to this length, and remove burrs. Prime both ends of the new section of pipe, the end of the pipe coming from the toilet and the inside end of the connecting coupling's spout. Also prime the inside of a PVC straight coupling. Cement all primed areas.

7. Push the straight coupling onto the end of the pipe coming from the toilet, and squeeze the new section of pipe into the other end of the coupling as well as the connecting coupling's side spout. Hold in place for 10 seconds. Install 1-5/8-inch galvanized screws through the holes in the toilet flange's lip and into the floor to secure it in place.

Tips & Warnings

• If the sewer design dictates that the toilet sewer line be made of ABS pipe, use ABS cement to seal the couplings to the pipe. No primer is needed.

References

• This Old House: Gluing PVC Pipe
• Hammer Zone: Gluing PVC Pipe and Fittings
• Wet Head Media: How To Install The Toilet Flange