Supply Pipes

Supply pipes, which bring pressurized water to your fixtures, are generally installed after the DWV pipes have been installed. Planning and running supply pipes is far less complicated than running DWV pipes. Supply pipes can be sloped in any direction and can run hither and yon, the only caveat being they must be connected correctly so they don’t leak.

Older homes often have gray-colored galvanized steel supply pipes. It’s a very good idea to replace these with either copper or PEX pipe because galvanized pipes corrode and clog, often leading to low water pressure and leaks after some decades. Some homes have white plastic PVC supply pipe, which has proved unreliable and may leak in time. Chlorinated polyvinyl chloride (CPVC) pipe, which is a cream-colored plastic, is more trustworthy. In the following pages, I’ll show how to install the two most common supply pipes: copper and PEX.

Tools for working with copper: standard-size tubing cutter; small tubing cutter for tight spaces; plumber’s tape (sanding mesh); wire brush; flux and a flux brush; propane torch; protective heat shield.

Working With Copper

Though PEX has surpassed it in popularity in some areas, copper is still a very common choice for supply pipe and is required by codes in many locales. The process of soldering copper pipes to fittings may seem daunting at first glance. But with less than an hour of practice, you will likely be able to “sweat” copper with ease.

-WHAT CAN GO WRONG: Deburring the cut end of copper pipes should become a habit because it’s important. Any burrs left in the pipe will slightly impede water flow, and a good number of them will seriously slow the flow.-

For the sake of clarity, I’ll first show sweating on a tabletop, although much sweating is done with pipes assembled in place. Though none of the steps for cutting and soldering copper are difficult, it is important that you do all of them. Skipping any step will result in faulty joints.

  • Measure for cutting pipes by holding them in place or using a tape measure. To cut, slip the pipe onto a tubing cutter and gently tighten the tool until the cutting wheel starts to bite into the copper.
  • Turn the tool all the way around the pipe until you stop feeling resistance. Then tighten the knob a bit and turn again until you stop meeting resistance. Repeat until the cut is complete.
  • Insert the reaming blade of the tool, or insert the head of a pair of pliers into the cut end and twist to remove burrs.
  • Dry-assemble a number of fittings and pipes to be sure they all fit, then dismantle them in order and start sweating. First, use a small piece of sandpaper called “plumber’s cloth” or a wire brush to burnish the outside ends of the pipes until they gleam brightly. Then do the same for the insides of the fittings.
  • Then apply a generous amount of flux to the burnished pipe ends and fitting insides.
  • Reassemble the pipes. (In a normal installation, you might cut, burnish, flux, and assemble 12 or more pieces, but for clarity, I’ll show sweating just one joint.) Turn on a propane torch and adjust so the flame makes a pointed shape about 4 in. to 6 in. long. Apply its tip to the fitting—not the pipe—until you see the flux begin to bubble.
  • Once the fitting is very hot, apply the tip of plumbing solder to a joint. It should melt and suck into the joint all around.
  • If it does not melt and suck in, reheat the fitting and start again. If two or more attempts fail, disassemble the parts and start again with burnishing and fluxing. Once all the ends of fitting have been soldered, brush them with flux to start smoothing things out, then wipe with a damp rag.

Running Copper Pipes Through Walls

Although it’s extra trouble to keep pipes in the center of studs, it is there where they are safe from the sharp tips of standard-length drywall screws or nails. You may choose to run pipes in simpler ways, but if so, be sure to use protective plates to protect them from drywall fasteners.

To tap into existing supply lines, be sure to shut off the water to those pipes and open faucets downstream to clear out all water.

  • Mark for cutting them in two places so they can be inserted into a T fitting.
  • Make the cuts using a small tubing cutter if space is tight. Tighten, twirl the cutter all the way around, tighten, and repeat until the cut is made.
  • Dry-fit the Ts. If you need to go around a pipe and stay in the center of a stud, use a number of “street elbows,” which have one female and one male end.
  • Measure to the centers of the pipes and mark nearby studs for cutting holes.
  • Use a right-angle drill to bore holes for the pipes to travel through.
  • Assemble all or most of an installation in a dry run, then disassemble, burnish, apply flux, reassemble, and solder all the joints.
 
STUBBING OUT: A strap like this holds copper pipes fi rmly in place where they emerge from the wall. Run pipes through the holes and screw the strap to studs. Apply fl ux and solder the pipes to the strap.

PROTECTIVE PLATE: Protective Plates A screw or nail can easily pierce copper pipe, causing a serious problem. If a pipe is run through the center of a 2x4, a 15⁄8-in. drywall screw driven through 1⁄2-in. drywall will not be able to reach it, so no protective nailing plate is required. (And most drywall screws are only 11⁄4 in. long.) If the pipe is nearer to the edge of the framing, be sure to attach a metal protective plate.

Working With PEX

Extruded or cross-linked polyethylene tubing, usually referred to as PEX pipe or tubing, is a common material for water supplies in many parts of the country. It is certainly the most economical solution: The material itself is far cheaper than copper, and it is much easier and quicker to install. Whereas sweating copper takes some practice and skill, connecting PEX is quite simple, as long as you make sure to fully tighten all the joints.

There are three different ways to join PEX. Pros may use a very expensive tool to make expansion joints. Another method uses crimp rings; this method is less expensive, but some people find it difficult to fully tighten joints. Here, I’ll show the simplest and least expensive method:

PEX clamps, which require some muscle but not as much as crimp rings. If you have only a few connections to make, consider using push-on (SharkBite) fittings, which are expensive but very easy to attach. PEX fittings may be plastic or metal. Both types have proved themselves reliable.

  • Measure for PEX lengths, taking into account any bends you may need to make. Because the tubing is so flexible, you can add an inch or so. Mark for cutting with a felt-tipped pen.
  • PEX is easy to cut. Do not use a saw, which will leave burrs that need to be scraped away. A PEX or tubing cutter like the type shown makes quick work of cutting.
  • Be sure the cut is nice and square; an angled cut may produce a joint that leaks. PEX fittings, which may be Ts, elbows, or other types, slip inside the tubing. To make a connection, first slip clamps onto each of the pipe ends.

WHAT CAN GO WRONG: PEX is even easier to puncture with a screw or nail than copper. Protect tubing with metal plates, as shown on p. 123.

  • Then slip the tubing onto the fitting at each end.
  • You may need to slide the clamps down a couple of inches, slide the pipes onto the fitting, and then slide the clamps back into position. Check to be sure that each clamp is positioned completely over the barbed end of the fitting, so it will fasten securely to the fitting. Slip the tip of the clamp tool onto the clamp’s wings. Use two hands to start tightening, then finish by tightening the 3Slip handles all the way together.
  • Check that the clamps are completely over the barbed fitting ends. If you cannot fully tighten the tool, or if the clamp is partway off the fitting’s barb or at an angle, cut the tubing and start again.

PEX tools & materials

PEX comes in red and blue colors, for hot and cold supplies. Cut with a tubing cutter made for PEX. Fittings such as elbows and Ts may be plastic or metal. Instead of the clamp tools and rings shown in the steps here, you may choose to use crimp rings and a crimping tool.

Turning a corner and stubbing out

PEX is just flexible enough to turn a right angle by itself, but doing so requires a fairly wide sweep, and you may accidentally crimp the tubing. Instead, use right-angle brackets. These are plastic, with tabs for attaching to a brace. You can also buy metal brackets without tabs, for tighter spots.

  • Attach wood framing braces between studs. Drive screws to attach the brackets, and snap the PEX into the brackets.
  • Cut the tubing to the same height.
  • PEX is rigid enough that you could actually poke it out of the wall and connect a stop valve directly to it, but for a firmer installation use special copper stub-outs. Screw plastic clamps just above the cut ends of the tubing.
  • Attach stubouts to the PEX ends, and snap them onto the clamps.

Transition Fittings

When connecting two different types of pipe—most commonly copper, PEX, or galvanized steel— use a fitting made for the purpose. In this example, a straight coupling is soldered onto a copper pipe and will be joined to PEX pipe with a straight coupling. Transition fittings may also be elbows or Ts and can accommodate any type of supply pipe.

Push-on fittings

Often referred to by the brand name SharkBite, push-on fittings resolve many supply-pipe situations with amazing ease. Once you buy the correct fitting and make clean cuts in pipe ends, you simply push the pipes into the fitting—usually with no tool required—to achieve a reliably watertight connection.

Fittings may be elbows, Ts, couplings, or other shapes. And they can connect to copper or PEX. The downside is the price—about $10 per fitting—but if you have only a few connections to make, or if you are in a tight or hard-to-reach spot, push-on fittings are well worth the cost. Here, we show installing a T fitting onto existing copper pipe, and connecting to PEX pipe.

  • Cut the copper pipe to receive the T, and use plumber’s cloth or a wire brush to remove any raised edges or burrs from pipe ends.
  • Push copper pipe into two ends of the fitting and make sure they seat all the way into the fitting.
  • Pull hard on all the pipes to make sure the connection holds. Push the PEX pipe into the remaining fitting. You can also use this fitting for CPVC pipe, if your home happens to have that.