November, 2001
Inspection News and Views from the American Society of Home Inspectors

Take Another Look at Polybutylene Plumbing


Several times a month, I get calls from real estate agents and home buyers seeking information about polybutylene (PB) plumbing, a product frequently installed in the Hampton Roads area of Virginia and nationwide during the 1980s and 1990s. They call me because I’m a plumbing contractor and a home inspector, who has been quoted on the topic in local newspaper articles.

 The answers to many of their questions can be found in Michael Casey’s article, “Checking for Leaks in Polybutylene Piping”, published in the 1995 July/August ASHI Reporter. Other questions I answer from the knowledge I gained installing PB for nearly eight years, and then repairing and replacing it for 18 more years.

In order to address how PB plumbing is affecting plumbers, real estate agents, insurers and home inspectors today; it helps to know its history, including the original installation practices.

Here comes polybutylene
With more than 25 years in the mechanical trades, I’ve seen a lot of new products come and go. In 1993 I was introduced to a flexible gray and blue water piping material known as polybutylene. Sold primarily under the brand name “Qest”, it was cheap and marketed as easy to install – using it could shave days off the average plumbing job. My plumbing company had been doing quality custom-built homes, primarily those piped with copper. As new home construction increased, I was asked to look at everything – single-family homes, large multi-family townhouse and condominium projects. To get this type of work, we needed to be fast, use code-approved materials, and have the lowest bid. Polybutylene helped many plumbers, including me, get these jobs.

At first PB systems were installed much like a copper or CPVC plastic pipe job, with sections of pipe cut to fit between two fittings. Turns were made with elbows and branch connections with tees. The actual connection process though was radically different. A new crimping method allowed the pipe and fitting to be put together without glues or solders, and lugging a large acetylene or propane tank from place to place was no longer necessary. The new process simply required crimping a small ring or band around the end of a piece of pipe that had a plastic barbed fitting inserted inside. A two-pipe size combination
-crimping tool that looked much like an average bolt cutter was basically the only new tool plumbers needed to add to their toolbox. At a cost of less than $100, it was a bargain.

Initially, aluminum crimp rings and plastic or “acetyl” fittings were the standard for polybutylene connections. But over-crimped joints were showing up as split or snapped off fittings. Under crimped or missed crimps were also leaking and there were expansion rate concerns as well. Measures to stop the PB problems were put into place.


Plastic or acetal type fittings with aluminum crimp rings

Local and national solutions for PB problems appeared to work

In the early years of polybutylene, it was common for code inspectors to give the okay to cover work following a visual inspection under normal city water pressure. But when quality-looking crimps occasionally leaked and popped joints flooded new homes, code inspectors began insisting on an elevated pressure test before the piping could be wrapped up. The thought was that under the higher pressure a defective or missed crimp would be discovered before the framed walls were covered up, therefore averting a future problem. Hydrostatic hand pumps were used to reach the new pressure demand, – some as high as 200 lbs. It worked! Missed crimps, under crimps and even over-crimped cracked fittings were found when they leaked or blew off during the new rough-in test.

Problematic aluminum rings and the acetyl fittings caused concern after the walls went up. The industries’ solution was to use copper or brass fittings along with copper crimp rings. In some localities, bags of the unused parts carted around in plumbing trucks were simply no longer accepted. However, some areas allowed existing stocks to be used, which could account for homes that have a mix of fittings and rings.


Copper fittings with copper crimp rings

The combination crimp tool was the next to go. Though popular when first sold, it wasn’t easy to place it around the ring and still get the proper crimp action required to set the joint. The combination tool also had space limitations, and it was difficult to keep it adjusted. By the mid 80s, suppliers stopped selling it, urged plumbers to throw it away and to replace it with a single crimping tool for each pipe size. Plumbers who purchased large quantities of PB pipe sometimes received the new tools free-of charge.


Combination crimp tool


On site and factory made manifold units

More changes

New tools and piping methods kept coming. Manifold units, both site built and factory manufactured, became popular. Manifold piping, often called “Home Run Plumbing”, involved pulling a series of 1/2" pipes from the hot and cold service locations behind each fixture to one location in or under the house.

By attaching the pipes to a large battery of tees or a manifold fed by one 3/4" hot or cold supply pipe, water was sent to each fixture through a dedicated pipe. PB was sold in 20-foot lengths and in rolls. Because the rolls of tubing could be purchased at 100 feet or more, the need to install fittings along the way on a manifold system was eliminated – a plus because fewer
fittings meant fewer potential leaks.

Although  substantially more pipe was required for the manifold system, pipe was inexpensive and the simplicity of the installation method meant pipe could be installed faster than for other systems, saving on labor costs. Some companies trained non-plumbers and laborers to install the pipe, thus cutting labor costs even more.

About the same time, copper stub out fittings – again factory- manufactured and site-built – were being used by some plumbers (including me) so they could plumb a house in a way that little or no polybutylene was exposed to view. This eliminated the cheap look – such as the flimsy wall extensions inherent with the product – and gave the house a more professional appearance. Copper stub out products allowed plumbers to put PB in houses where builders previously insisted on all copper. When the walls went up, the house appeared to be piped entirely in copper. It looked good, and where it was done well, this system of piping confounds many homeowners, real estate agents and even home inspectors today.



Specific PB problems

Improperly used fittings
A large compression type fitting was primarily used at yard lines, as a repair part and by do-it- yourselfers.  Still sold today, they can be found as tees, elbows and various adapters. Generally easy to install, they rarely leak if just a little more than hand tightened. But when misaligned or over- tightened, they can crack and slip off, or the compression ring itself can cut into the pipe.

Although these compression fittings and even the pipe itself is not recommended for use in continuous loop heating systems, both were used by plumbers and HVAC installers on Apollo or Hydro type systems. In the past, both were often approved by some code inspectors even when used in this manner.

A loop type heating system uses the house gas water heater to heat the home. It can produce dramatic temperature changes to the pipe and fittings. Unlike water-filled systems that operate on lower water pressures, the fitting can work loose and leak. It’s been my experience that leaks occur at the fittings when water-filled systems are used this way. Because a chemical reaction between the pipe and coil may be taking place, leaks occur along the pipe wall as well. Portions, if not all of the hydro system, can be found in attics under house pressure, where a leak can be catastrophic, often bringing down a ceiling.

Hose bib advisory frequently ignored

It says, “Hose bibs shall not be directly connected to PB tubing,” in the 1993 Plastic Pipe and Fittings Association’s edition of the “PB Handbook ONE”. This advice was widely ignored for polybutylene. Barb adapters were often soldered to a hose bib, and the pipe directly attached. When first screwed to the wall covering, the valves were secure. But once the screws worked loose, the valve could twist off completely or dangle from the wall.

Support issues
To support copper pipe diameters of less than one inch, a strap about every six feet is acceptable for horizontal support. To support CPVC pipe, a strap every three feet is generally acceptable for horizontal support. Polybutylene, however, required a strap every 32", and when filled with water, it still drooped. The sharp edges of some special pipe straps and talons used for PB were a stated concern. I’ve frequently repaired large dangling clusters of PB fittings in crawl spaces and pipes that were woven through attics like garden hoses, with no strapping at all. It’s not unusual to find a cut pipe or pinhole leak at an improper strap.

Backfilling guidelines overlooked
Professional plumbers generally take pride in their pipe installations, but there are circumstances where things get overlooked. While backfilling a trench for example, it’s easy for debris to get pushed in with the dirt. Soda cans, stones and wood scraps get dumped in a ditch with the fill dirt. Over the years, I’ve found these little construction artifacts in the same hole as the site of a leak.

Backfilling guidelines are spelled out in the “PB Handbook One”. With regard to PB, the book states, “Do not use clay, silt or rocky backfill. Remove the construction materials or foreign objects from the trench prior to backfilling.”

Yet I continue to find trash pressed against the pipe wall when repairing a yard service line leak.

In heavy load traffic areas, a minimum depth of 24" was required to help protect the pipe from crush concerns. But like in many warmer climates, the code in the Hampton Roads Virginia area only required a depth of 18" for freeze protection. So 18" it was.

The “PB Handbook One” manual also states the pipe should be pressurized with water before covering to reveal possible damage to the pipe and to keep it from being compressed into an oval shape. My experience was that plumbers often rolled the pipe from the street to the house, taped off both ends, and then covered it up. Later the pipe would be dug out at the ends, connected to complete the water service, then pressurized. Slab piping was done much the same way. Plumbers trusted this material straight off the rack. There was rarely a leak with new pipe and pressurizing it before covering it just took up time and wasted fittings. Today, when trying to make an underground service pipe repair on older pipe, I find pipe that is simply too flattened to take a fitting or to hold a fitting leak-free. Sometimes the pipe splits along the sidewall as I try to repair it.

Sunlight – one of several PB enemies
Sunlight, high levels of chlorine, solvents, cutting oils, solder flux and pipe dope are just a few of the known enemies of polybutylene. While recommendations caution against exposing polybutylene to sunlight for more than 30 days, it was often hauled around in an open truck for days. On the building site, it extended above roughed-out slab jobs for several more days or even weeks before being wrapped up and the house built around it. PB doesn’t change color or act differently on day 31, and because it has passed through several hands, no one knew how long it had been exposed to UV rays – so it was used.

Information about PB sorely lacking

Getting accurate information about polybutylene problems was itself a problem. Looking back, I’m alarmed by plumbers’ lack of information about PB. When it was introduced, I attended a class on installing it, which was more marketing than training. Plumbers were told about PB’s outstanding ability to hold up in harsh water situations. Fitting concerns were never mentioned. Now even durability is questioned.

As Michael Casey pointed out in his article, the Uniform Plumbing Code removed PB as an acceptable water distribution material in 1991. Yet, in my 1995 International Plumbing Codebook, the product is still listed as approved. At that time it was still going into houses in Virginia Beach, Chesapeake and other Hampton Roads cities. When I recently discovered the pipe in a house built in 1997, I quizzed a local code inspector to determine if the material was still accepted. He said the use of polybutylene isn’t actually prohibited. But since manufacturing of the product had stopped, code officials felt it was a moot point. He also confided to me that he had seen service lines installed with PB after 1997.

More to come next month.