About Re-piping

Vertical Vs Valance

As Owners receive various proposals from contractors they will find major variations between quotes. We are providing you with some general information on the two different types of retrofit systems available.

There are two types of retrofit plumbing systems being installed in existing buildings, a VERTICAL SYSTEM and a LATERAL/VALANCE SYSTEM. Cambridge has installed both types of systems in existing buildings.

Generally a horizontal system would only be considered for a high-rise building. Buildings of four levels or less are almost always a vertical system.

Vertical System

Virtually every multi-family building was originally constructed with a vertical water pipe system. This system typically has a pipe that runs vertically in the wall behind the fixture(s). These pipes are called risers. Typically each suite will have two risers, one for the kitchen and one for the bathroom. The wall is usually opened on the opposite side of the fixture for access to install new piping. Once the new piping is installed, drywall is installed and finished. The wall is then painted and the re-piping project is complete. Upon completion there are no visible differences to the suite's architecture due to re-piping.

Vertical System Advantages:

  • Usually no valances are required throughout suites or common hallways.
  • Only the areas where pipes are replaced need drywall repairs and painting.
  • Painting within suites due to the retrofit is reduced by 50-75%, when compared with the lateral/valance system.
  • Approximately 40% less pipe is used in a vertical system resulting in less heat loss and a more efficient system.
  • There is less water noise within suites because piping is not distributed throughout suites.
  • No need to relocated fire alarms, smoke detectors, exit lights and lighting fixtures due to the addition of valances to enclose new piping.
  • The installation process is completed quicker then a lateral/valance system and with less dust, debris and noise within suites.
  • Bathroom ceilings are not usually cut and removed as they are with a lateral/valance system.
  • Does not take away from ceiling space in common hallways or in suites.
  • Water temperature and pressures are more consistent then a valance system.
  • As you may know, every time a building's water is turned off there is a risk of more leaks when water is reinstated. This system usually requires fewer water shutdowns during repiping.

Vertical System - Water Isolation:

  • Isolation is provided to each riser.
  • Example: In an eight-storey building you can individually isolate the kitchens from 101-801 while to the rest of the building, water remains undisturbed. In effect, eight kitchens are isolated instead of the complete building being shutdown. The same principle applies to the bathrooms. In consideration that most buildings currently have only one shutoff valve for the whole building, being able to isolate each riser is a great convenience over the original installation. A building taller than eleven storeys would usually have two sets of valves, one set for floors 1 - 11 and a second set for floors 12 and up.

Valance System

This system usually uses one set of vertical pipes from the boiler room to the top floor. These pipes are usually  located in an area of the common corridor or in some cases, an abandon garbage chute. These pipes are called the main lines. On each typical floor, branch lines are connected to the main and distributed at the ceiling level in a valance into each suite. From inside the suite to the fixtures the pipes are also run in a valance at ceiling level. The valances are usually constructed of drywall and are approximately 10" x 10" in size. If the bathroom or kitchen is twenty feet inside the suite then the valance will run twenty feet through the suite to the kitchen or bathroom.

Usually this system provides isolation valves to each floor and as an option to each suite. This system allows one suite to be isolated at a time while the remainder of the building does not need to have the water shutdown.

Valance System Disadvantages:

  • Requires additional insuite cutting, patching and painting resulting in more inconvenience and dust for residents.
  • Not visually attractive.
  • Valance runs throughout the suite to get to kitchens and bathrooms.
  • Requires valances to be painted throughout the suite.
  • Proves to be a problem if wall papering is present and there is no additional wall paper for valances.
  • This system typically uses approximately 40% more piping then a vertical system, which results in more water within the piping to be heated and greater heat loss resulting in an increased operating cost.
  • Approximately 40% more piping is used on this type of installation. This means 40% more piping must be maintained in the future.
  • Repiping horizontally requires a water shutdown to the complete building on a daily basis.
  • Commonly when a buildings water supply is turned off then on, new pinhole leaks may appear particularly on a system with advanced corrosion.
  • Valances in common hallways may prove to be a problem in moving couches and other furniture.
  • Valances usually run on one side of the common hallway and cross over to each suite on the other side. This may interfere with lighting in hallways and is not an attractive feature.
  • Fire alarm bells and smoke detectors may have to be relocated and services may be interrupted.
  • The sound of running water is present wherever the valance system is installed.
  • Bathroom ceilings are usually opened for pipe installation. This is not usually required with a vertical system.
  • The mains are usually located in the common hallway that require a drywall enclosure and painting.
  • Most piping is supported horizontally. This requires holes to be drilled into the slab for support anchors. These holes are drilled with a rotary drill and the sound carries throughout the building. The Residents can expect the noise of drilling that spreads throughout the building to be heard throughout each day of work. A typical 50-unit high-rise building would require approximately 2,000 holes to be drilled.

Most existing buildings have only one shutoff valve for the entire building. A new vertical riser system allows each riser to be isolated rather than shutting down the entire suite or building. Isolating each floor with a vertical system is also possible. The result is the isolation is limited to groups of fixtures rather then by the suite. Example: An existing 50-unit high-rise building that originally only had one shutoff for the entire building would now have approximately 10 sets of shutoff valves to the new system.

Variations of each system may differ for each individual building, however, the information provided may help you to understand the basics of the two different systems.