Since we shall continually refer to the term, roughing-in, it would be well to understand exactly what it means. Roughing-in refers to actual installation. Plumbing work that is completely roughed-in is ready for fixtures. As long as it remains exposed — before the walls, partitions, and floors are completed—the plumbing is described ; as roughed-in.
Roughing-in includes the placement and connections of pipes, fittings, and fixtures from the connection of the house sewer in the basement to the top of the vent stack extending through the roof, and all water lines up to but not connected to fixtures.
There is nothing temporary about roughed-in work. Roughed-in piping is meant to be permanent and as secure as possible against freezing, settlement, and vibration. All connections are made with care and they are securely tightened to prevent leaks.
Since roughing-in includes the central supply and drainage lines, you will be concerned with the heavier types of pipe in their longer lengths. As your entire plumbing system depends on the efficiency of your main waste and supply piping, be sure that you have the correct tools and materials before you begin. Also make certain that you are capable of completing a major installation, and that you, an amateur, are permitted to do so.
During the roughing-in, you will need many of the tools described elsewere.. These will include pipe cutters and threaders, chisels, caulking irons, saws, wrenches, files, and a plumb bob. You will also find good use for a carpenter's level, a brace and bits, a square, and a machinist's hammer. A 6-foot rule is essential, but use a wooden rather than a steel one, as there is always the danger of the rule's contacting an electric outlet or wire.
Strengthening and supporting piping
Inadequate bracing or supporting of pipe causes such major breakdowns in the plumbing system as joints loosening, excessive leakage, vibration, and sagging. Since each section of pipe, in addition to its own weight, has the added strain of the pipe connected to it and the weight of the water passing through it, good supports are necessary.
Long vertical runs, such as the soil stack, are particularly vulnerable. However, if the pipe is braced well at bottom and top, and if each ten feet of vertical run is held by straps or clamps, there is little danger of undue trouble.
Horizontal pipe must also be held in place along its length. Cast iron or brass installations, because they require more fittings, need more support than copper tubing. Limited sagging in copper tubing has no appreciable effect on the system, but it can cause fittings on cast iron pipe to loosen and rupture. Straps, hangers, taping, and other kinds of support, no more than ten feet apart, will prevent dangerous sagging.