PVC (Polyvinyl chloride) is a hard, white plastic used for household sewer or vent lines. The sections generally come in 8-foot lengths with a diameter range of 1 1/2 to 4 inches, and join together with primer, cement and couplings. Extending a previously installed PVC pipe requires cutting all new pipe sections to length before installing them in place. Horizontal pipelines must be installed at a gradient for sewer to travel down the pipeline, so the local city building department must be consulted first for the correct gradient in your area.
Measure and mark the first two new sections of PVC pipe to the required length. Use a handsaw or circular saw to make a straight perpendicular cut though the pipes at the marks. Scrape off all large burrs from the sawed pipe ends and remove smaller plastic fragments with 80-grit sandpaper.
Brush PVC primer around the outside end of the existing PVC pipe to a width of 3/4-inch. Also apply primer around one outside end of the first new pipe section as well as the inside of a PVC coupling. Brush PVC cement on to all three primed areas.
Push the coupling on to the end of the existing PVC pipe, and then slide the cemented end of the first new pipe section into the remaining end of the coupling. Hold the pipes to the coupling for five seconds while the cement starts to set.
Brush primer around one outside end of the second new pipe section as well as the remaining outside end of the first new pipe section. Then prime the inside of another PVC coupling. Cement all three primed areas. Push the coupling on to the end of the first new pipe section and the cemented end of the second pipe section into the other end of the coupling. Hold the pipes to the coupling for five seconds. Measure, cut and install in like fashion all necessary new PVC pipes sections until the water fixture is reached.