By Rob Fanjoy
Home-run plumbing is becoming more popular because of its performance characteristics and easier installation. Now, a new approach toward designing and building homes promises to maximize those advantages and apply them to all utilities, including electrical, HVAC and communications.
The Partnership for Advancing Technology in Housing Concept Home illustrates methods for disentangling systems to accommodate both current stability and future change in the homeowner's housing situation. With its roots in a commercial building concept known as "open building," the fundamental idea is to separate the primary systems of a home--the structure, the utilities and the floor plan. The structure is built for long-term durability, while the utilities and interior walls are configured to facilitate future changes.
In the PATH Concept Home, all mechanical systems can be accessed through removable panels in ceilings, walls and floors. This lends itself particularly to home-run plumbing, which has dedicated lines running through chases, interstitial walls and open-web floor joists. Vertical runs that go from floor to floor are usually located alongside stairwells, as these areas are typically less likely to be altered except during drastic remodeling changes. This system further reduces the already shortened installation time associated with home-run plumbing; PATH estimates it could save an additional 10 to 20 percent on overall plumbing costs.
Other home-run tips and tricks
Even if you're not working in a disentangled or "open building" home, there are some techniques that will ensure a speedy, high-quality and profitable job for you and top-notch performance for the homeowner:
- While home-run plumbing systems and PEX tubing have received blanket code approval in most states, there may still be some restrictions within individual jurisdictions. Make sure you have the proper approvals before beginning the work.
- Cross-linked polyethylene lines replace pipe in home-run plumbing systems, but they call for some extra attention, at least during installation. "Hot-water PEX lines can expand as much as one foot for every 100 feet in length, which can make for some unsightly droops between floor joists," says Dave Yates, president of F.W. Behler Inc., plumbing contractors in York, Pa. "My guys usually install the tubing with a few loops in between some of the joists to stop that droop."
- Manifolds should be located in a convenient, accessible location in the basement or service closet. Dave recommends installation close to where the water service enters the house, yet still near the hot water heater (minimum clearances of 36" vertical and 18" horizontal from the water heater).
- A tee connection should be placed on the main supply line upstream of the PEX system to flush the street line prior to running water through the manifold. Street lines often gather sand or dirt during construction, which can ruin the manifold valves.
- Crimping tools may eventually wear out, so a simple, inexpensive gauge available from PEX suppliers can check the crimps to ensure adequate compression.
- In especially long runs to a shower or sink where hot water takes a while to arrive, Yates recommends installing a simple recirculating pump to save water and energy.
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