How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manufactured and modular homes
What does polybutylene pipe look like? Why is it a problem?
Sunday, October 21, 2018
Polybutylene piping (also called “PB” in the trades) was used in residential water supply piping in Florida from 1978 to 1995. It was billed as “the pipe of the future” at first, and its low cost and easy installation made it an alternative to traditional copper water piping. PB was especially prevalent in mobile homes manufactured during the 1980s and early 1990s, but we also see it installed in site-built homes of the same era--occasionally even including estate-type homes in Haile Plantation and similar neighborhoods.
But throughout the 1980s lawsuits, claiming that defective manufacturing and installation had caused hundreds of millions of dollars of water damage from ruptured pipes, began to mount into the thousands. Although the manufacturers never acknowledged that PB pipe is defective, they eventually agreed to fund a class action settlement for just under a billion dollars to resolve homeowner claims. The period for filing a claim ended in 2007.
While the exact cause is uncertain, it is believed that the oxidants (such as chlorine) in public water systems react with the plastic, causing it to flake and become brittle. As the integrity of the piping deteriorates, tiny fractures develop, which can expand over time and cause a sudden failure of the pipe and resulting water damage.
We will check for PB piping during your home inspection, and advise you if it is present in the home’s water supply system. To check for yourself, look for flexible pipe that is gray, with copper-color band connections, like in the photo at the top of the page taken under a bathroom sink at a manufactured home. PB pipe is easier to spot in a mobile home because it extends well into cabinetry. Gray is the most common color used, but polybutylene can also be blue or black in color. It is usually stamped with the marking “PB2110.” The piping is 1/2” to 1” in diameter.
The easiest place to observe it in a site-built home is at the pipe feeds coming out of the wall to the water heater—like in the photos below, again with the copper rings crimped around connections that are a defining characteristic for identifying PB pipe. Because it can be covered with dust or crud, you may have to wipe the pipe to confirm that it is polybutylene. PB pipe can sometimes also be observed under the sinks and toilets, peeking out from behind the shut-off valve. But only a small length of pipe sticks out of the wall at these locations and is often covered up by a chrome escutcheon ring. Polybutylene is not used as drain piping.
Replacement of the water supply piping in a typical home costs $4,000 to $5,000, and is the only remedy available. Because of the public awareness of the risks involved with PB piping, its presence may reduce a home’s value in the marketplace. It can also cause higher denial of coverage or extremely high deductible for water damage with your homeowner’s insurance.
Also, see our blog posts When was polybutylene pipe banned? and Do you have to disclose polybutylene pipes to a homebuyer?
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