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Polybutylene pipes were very popular from the 1970s to the mid-1990s since they were easy to make and flexible. Over time, however, the pipes and connections began to fail at an alarming rate. This can lead to leaks inside walls or more visible water damage, so the pipes no longer comply with today’s building codes. Tubing made from PEX, or cross-linked polyethylene, is an alternative to polybutylene that’s far more reliable and has been used safely for the past two decades.
Replacing your old piping with PEX involves advanced plumbing techniques, and you’ll want to make sure your new tubing is up to code, so it’s best to leave this job to a licensed plumber. However, you may still wonder why PEX is better and how the replacement process works.
This Old House plumbing and heating expert Richard Trethewey has the answers to your polybutylene and PEX questions.
Why Polybutylene Pipes Fail
Polybutylene pipes can fail because of the chemical reactions between chlorine and other oxidants in the water. Ultimately, this degradation weakens the oil-based resin material and increases the risk of leaks and bursts.
Some polybutylene pipe manufacturers have also struggled with defective products. Paired with stress on fittings and connections, all three causes form a trifecta of unreliability for your home.
How To Identify Polybutylene Pipes
Polybutylene pipes can be gray, blue, or black. Their flexible plastic has the code “PB2110” stamped on the side. They would also have been installed sometime between 1978 and 1995.
If you find these characteristics anywhere in your home’s piping, don’t wait for disaster. Replacing it early comes with upfront costs, but repairing water damage is much more expensive by comparison.
Why PEX Is Better Than Polybutylene
PEX (cross-linked polyethylene) tubing offers several advantages compared to its predecessors. Here are just a few of them:
- Chemical composition: The cross-linked molecular structure of PEX makes it more durable.
- Flexibility: PEX is a flexible material. You’ll still need fittings and connectors to route the tubing and hold it together, but you may not need as many, reducing the number of potential failure points in the future.
- Temperature resistance: PEX tubing was first used for radiant floor heating systems. When Trethewey heats a polybutylene pipe with a heat gun, it pulls apart like taffy, while the PEX tubing holds its strength for longer. PEX is also resistant to both freezing and bursting in the cold.
- Reliability and longevity: PEX has been used for potable water systems for over 20 years. Better durability also means a better life span.
Steps To Replace Polybutylene Pipes with PEX
Replacing polybutylene pipes with PEX, especially throughout a home, requires careful planning and precise execution. If your home has polybutylene plumbing exclusively or uses it for key parts of your routine, you may need to plan for a temporary place to stay while the job’s in progress.
During the consultation and estimate process, your plumber will identify and locate where polybutylene pipes are in your home. They’ll plan a new network that considers all your fixtures and appliances and is efficient on materials. Some fixtures aren’t compatible with PEX tubing, so they’ll also let you know which areas may need new fixtures or special adapters.
When installing the new tubing, the plumber shuts off the main water supply and opens all faucets to drain any remaining water. Then, they’ll begin removing the old plumbing. Sometimes, the pipes are in hard-to-reach areas. Specialized tools can make the job easier, though your plumber may also need to cut access holes in a floor, ceiling, or wall. This can be exceptionally painful if the plumbing runs throughout the walls of your home.
Once the old pipes are out, they’ll run the new PEX through everywhere the polybutylene used to go and to your fixtures. A special expansion tool widens the tubing so fittings can go inside. “The tubing and the sleeve have a memory,” says Trethewey, “and will return to their original dimension, which makes a watertight connection.”
Finally, they’ll turn the water back on and check the plumbing system for leaks. If everything looks watertight, they’ll patch up the walls and access points.
Cost Considerations When Replacing Polybutylene Pipes With PEX
Several factors affect how much it costs to replace polybutylene pipes with PEX. They include the following:
- Accessibility of existing pipes: Piping that’s harder to access will often translate to higher labor costs.
- Number of fixtures and appliances: The more fixtures and appliances you need to connect PEX tubing to, the more money you’ll spend on both materials and labor.
- Quality of PEX tubing and fittings used: High-quality tubing and fittings tend to last longer and have better durability. It’s more expensive up front, but you’ll pay less for maintenance in the long term.
- Your plumbing system’s layout: Some homes use a mix of polybutylene pipes and other plumbing and tubing types. If your home is one of them, you may be able to get away with a partial system replacement, which is far cheaper than a whole-home project.
- Size of your home: Larger homes have larger, more complex plumbing systems that cost more money to replace.
Get quotes from multiple different licensed plumbers to compare their recommendations and rates. However, don’t base your company choice on who offers the cheapest prices. Instead, look for a trusted and experienced company that delivers the best value for your dollar.
Just as well, when you schedule your PEX plumbing work is just as important as who you hire to do the job. You might get discounted labor rates by scheduling the project during an off-peak season.
Maintenance and Care for PEX Plumbing
Once your PEX plumbing is installed, here’s how to protect its longevity:
- Use appropriate hangers and supports to prevent sagging and keep the tubing stable.
- Avoid exposing PEX to direct sunlight.
- Insulate exposed PEX pipes to prevent freezing.
- Schedule regular plumbing inspections to catch any issues early.
