Plumbing's Next Generation

Plumbing can be a major hassle for professional remodelers. Pipes take up space and limit where walls can go and which walls can come down. It also can take days for a plumber to reroute conventional piping. Some of these systems leave little room for plumbing upgrades or make it difficult for homeowners to reach shutoff valves.

January 31, 2007

Put to the Test

Plumbers string PEX piping from the central manifold directly to individual fixtures.

Plumbing can be a major hassle for professional remodelers. Pipes take up space and limit where walls can go and which walls can come down. It also can take days for a plumber to reroute conventional piping. Some of these systems leave little room for plumbing upgrades or make it difficult for homeowners to reach shutoff valves. So, what better options do you have?

How about home-run plumbing?

For You and Your Client

Home-run plumbing is a simple and affordable plumbing upgrade using PEX — cross-lined polyethylene piping — that simplifies the job for the contractor, particularly during additions. Home-run plumbing speeds construction, which can lower costs — and inconvenience to your client — on all remodels that include replacing old piping or making other major plumbing modifications. You also have the benefit of knowing that you've delivered a higher-quality product.

This innovative plumbing system uses a central plumbing manifold — essentially, a plumbing fuse box — to feed hot and cold water through flexible supply lines to individual fixtures. Here's how it works:

  • The manifold provides a central point of water flow, with the option of shutoff valves to each fixture. The manifold accepts all common supply line sizes, down to 38 inch.
  • Parallel supply lines, one to each fixture, require few or no fittings. That means less work for the plumber and more consistent water pressure for the homeowner.
  • The supply lines comprise PEX, which means the flexible piping can easily be threaded around structural members, through walls and through crawl spaces. Although PEX needs to be fastened at intervals, it still results in a lot less cutting and welding or gluing for the plumber. That means less time spent on the job.

According to research by the Partnership for Advancing Technology in Housing (PATH) and the NAHB Research Center, PEX piping performs better and costs less to install than copper (see sidebar, "Put to the Test").


It is important to properly install and care for home-run plumbing.

First, install the central manifold in a convenient and accessible location, such as a basement wall or a service closet. This allows easy access for shutoff to individual fixtures.

Install manifolds near the water heater. Minimum clearances of 36 inches vertically and 18 inches horizontally are needed between a thermoplastic manifold and a water heater.

A plumber connects a hot water supply pipe made from PEX to the central manifold. Compared to copper piping, PEX can save 20 percent on the installation.

Ensure that PEX piping has 12 inches vertical clearance and 6 inches horizontal clearance from other heat sources, such as light fixtures, gas flues and heating appliances. PEX can melt, distort or crack if exposed to excessive heat, so during installation, shield it from high-temperature sources, such as torches used for soldering other equipment. PEX also should not be exposed to freezing temperatures or sunlight. Protect it from abrasive surfaces, which can damage the pipe as well. Follow the manufacturer's installation instructions, and check your local code provisions.

Around Corners

Too often, plumbing constrains remodelers from recommending designs they want.

"We were looking for the design flexibility home-run plumbing gives you in a remodeling project," says Tommy Strong, a project manager for Brothers Strong Residential Design and Build in Houston. "The existing structure can be very restricting, and copper is difficult to work with in small spaces. Above all, flexible piping is ideal in retrofits or additions where you are working with the existing piping," he says.

Strong cites one job where the company was hired to expand a one-car garage into a three-car garage with a living space, including two full bathrooms on the second floor. Using copper would have been much more difficult and labor intensive to extend the piping from the old part of the home into the new bathrooms.

"There were several tight spots as we were trying to get from old areas to new areas," Strong says. "We probably would've had to make some design compromises if we used hard piping, such as building out some fir downs or lowering the cathedral ceiling a little bit. With PEX, we didn't have to worry about that."

It only took one day to install the plumbing for the two-bathroom addition. Other plumbing configurations using PEX can save time, including remote manifold, trunk and branch and combinations of the three. Each has its own cost/benefit combinations, so review your options.

The central manifold allows individual water supply pipes made from PEX to go directly to the fixture. How water is delivered up to 50 percent faster than with traditional copper supply piping.

Costs and Savings

The financial bottom line often keeps remodelers from trying less traditional construction technologies. But with home-run plumbing, money shouldn't be an issue.

PEX piping and a manifold usually cost less to install than conventional plumbing because there is less cutting and no pipe to solder or glue. There is less chance of leaks after pressure testing and easier access to joints for repairs. The entire test-out time should also be shorter.

However, Brothers Strong president Michael Strong warns that not all plumbers are willing to share those cost savings with you.

"One of the problems that we are struggling with is that our plumbers are not giving us the price break for the plumbing installation when we know the labor is a fraction of normal costs," says Michael Strong.

When plumbers give estimates for a project, Strong says they often claim it's going to take longer because it's non-traditional technology.

However, the marketplace is full of plumbers with some — if not extensive — experience with PEX piping. You might need to let your plumber know that you understand the cost and time savings available through PEX and you expect to see those savings in the estimate.

Materials cost is also comparable. For a manifold plumbing system, the price tag varies depending on number of ports, whether they include gate valves and the materials they contain. Some systems run as little as $35, while high-end manifolds can exceed $200.

However, local supply of PEX and manifolds heavily influences cost competitiveness. Ask your suppliers if they keep it in stock. And if they don't, ask why not.

Homeowner's View

Presenting your customers with a new product might require you to provide a little education, too.

"It's still a new enough technology where you can't walk into a house and start plumbing with it and not have the homeowner be part of that decision-making process," Michael Strong says. But home-run plumbing should be an easy sell, considering its numerous benefits to homeowners.

The most exciting feature for many clients will be the speed with which hot water gets to the faucet. Tests show that PEX delivers hot water 30 percent faster than standard piping (see sidebar, "Put to the Test). Those extra minutes can mean a lot to homeowners rushing through their morning routine.

If your clients have an old plumbing system, shutting off the water to one leaky pipe means shutting off the whole system. With a centralized shut-off valve at each supply line, plumbing emergencies, repairs and upgrades are much easier to handle.

Plus, emergencies should be far less common because most plumbing leaks occur at the joints in fittings. PEX home-run systems require few or no fittings, so leaks are less likely.

PEX piping also expands and contracts more easily than copper or other plastic piping. This means it's less likely to freeze and burst if your client forgets to turn off the water before going away on vacation.

Since PEX piping insulates better than metal pipes, the cold water pipes won't sweat as much on humid days, and your clients might even save a little money heating water.

The next generation of piping is here. With little or no extra investment, you can have more flexibility in your next project and improve the plumbing for your client.

Author Information
Scott T. Shepherd writes about better building practices on behalf of the Partnership for Advancing Technology in Housing ( PATH is administered by the U.S. Department of Housing and Urban Development. Learn more at


Put to the Test

Is PEX piping really better than copper?

That question confronting remodelers was also on the minds of PATH and the NAHB Research Center. In 2005, the two collaborated with Nebraska builder Fernando Pagés Ruiz to compare installation, material cost and performance at Pagés Ruiz's Liberty Village project in Lincoln, Neb. They tested four homes with identical floor plans and identical demands on the plumbing system. Two homes used copper, and two homes used home-run plumbing. The results were definitive: the home run system significantly reduced installation time over copper, which required additional labor for fittings.

For material costs, copper was marginally less expensive due to the central manifold and the limited local availability of PEX. However, installation and material costs for home-run plumbing were still 28 percent less.

In performance testing, PEX delivered hot water an average of 30 percent quicker to the lavatories farthest from the hot water heaters.

Results of the Liberty Village evaluation are available at Click on "Practices."


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