Fixtures Rough in

We’ll look at a variety of common plumbing improvements that involve changing or installing plumbing fixtures. Of course, to install a fixture, the proper configuration of pipes must be in place-usually in the wall and/or under the floor. The first stage of preparing for fixtures is known as “roughing-in” the plumbing.

The proper rough-in for fixtures depends upon a number of factors, notably the way the fixture is made, the room’s layout and building and plumbing codes(be sure to check your local codes). When you buy a new sink, toilet or similar fixture, rough-in templates and instructions are nearly always included with the product. Carefully read the manufacturer’s directions before roughing in a fixture.

Following are directions for roughing-in two common fixture improvements: a bathroom sink and a toilet.

A bathroom sink is fairly easy to install and has little effect on a drain’s efficiency, though a new sink must be vented as stipulated by your local code. You can run pipes along the surface of a wall in certain circumstances, but it’s best to handle all rough-in plumbing during the framing stage of construction, when the walls are open, so pipes may be concealed. Otherwise, in most cases, you’ll have to remove wall surface materials and replace them when you’re finished.

A toilet is the most troublesome fixture to install in a house because it requires its own vent(2-inch minimum) and at least a 3-inch drain. If it is on a branch drain, a toilet cannot be upstream from a sink or shower

Roughing-In Bathroom Sink

In addition to vent connections, you will need ½-inch hot-and cold-water supply stubouts; shutoff valves; transition fittings, if necessary; and flexible riser tubes. You may also need water­hammer arresters on the supply pipes to prevent pipes from banging.

Sloping A Drain

The maximum distance allowed from the trap to the stack or vent is coiled the critical distance. The drain outlet cannot be below the level of the trap’s crown weir. If the fixture drain is vented properly within the critical distance, the drainpipe may run on indefinitely to the actual stack or main drain.

Roughing-In A Toilet

The closet bend and toilet floor flange must be roughed in first(be sure to allow for the wall covering material’s thickness when measuring the outlet’s distance from framing). The floor flange must be positioned at the level of the eventual finished floor. You will also need the following piping supplies: ½-inch riser tube, a cold-water supply stubout, shutoff valve, and flexible riser tube.

Framing A Toilet Drain

When installing a new toilet, you may need to cut an entire section out of a joist to accommodate the drain piping. Reinforce that section by nailing doubled headers on both sides of the cut.