Installing Plastic Drainpipe

Intro

Plastic PVC pipe and fittings are inexpensive and easy to install. However, do not take this work lightly. Once glued together a joint is rock-hard and cannot be adjusted. If you make a mistake, you'll have to cut out the section and start over.

Making a dry run
To prevent a mistake, cut and assemble the pipes in a dry run: Cut and temporarily join five or six pipes and fittings and make sure that the last pipe in the run is facing the right direction. Use a felt-tip pen to make alignment marks on all the joints where the fitting must face correctly. Disassemble, keeping careful track of the order of installation. Apply primer to each pipe end and each fitting. Apply cement and join each pipe in order.

Checklist

Time
About an hour to cut and assemble five or six pipes and fittings

Tools
Felt-tip marker, PVC saw or backsaw and miter box or power miter saw, deburring tool

Skills
Sawing, measuring, working methodically

Prep
Make a drawing of the drain/vent assembly; clear a path for the pipes

Materials
Primer and cement for your type and size of pipe

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Step 1

When measuring allow for the distance the pipe will travel inside the fitting. Use a felt-tip marker to mark the pipe. You can use a hacksaw or backsaw to cut PVC, but a plastic-pipe saw is easier to use. A power miter saw with a fine-cutting blade is easiest of all. Cut it square.

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Step 2

Remove all the burrs from the cut pipe end. You can do this by scraping with a knife, but a deburring tool does a better job and is easier to use. Assemble cut pipes and fittings in a dry run.

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What If... You Are Connecting ABS Pipe?

Most codes require PVC for drain lines, but if you already have black ABS pipe in your home, local codes may allow you to add to your system using the same material instead of making a transition to PVC.

Cut and assemble the black ABS pipe in much the same way as you would PVC pipe. Use a plastic-cutting saw or backsaw with a miter box, remove the burrs, and put pipe and fittings together in a dry run. Use a sharpened, light-color crayon to make alignment marks.

Instead of primer, apply ABS cleaner to pipe ends and fitting openings. Use special ABS cement to glue together the pieces. Push the pieces together and twist.

To connect PVC pipe to existing ABS pipe, use a no-hub fitting.

Step 3

Apply primer to the inside of the fitting openings and to the pipe ends. The applicator should be wet enough to produce a fairly dark line but not so wet that the primer drips. Place the pieces where they will not get dirty. If debris sticks to the primer, it will be difficult to join the pipes.

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Apply cement to the inside of one fitting

Step 4

Apply cement to the inside of one fitting opening and to the end of one pipe. Work quickly -- the cement starts to set up in a few seconds.

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Step 5

Push the pipe into the fitting and twist so the alignment marks line up. Hold for a few seconds, then wipe with a damp cloth. In a minute the joint will be strong enough so you can assemble the next piece. After 15 minutes you can run unpressurized wastewater through the pipes.

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