How To Replace Polybutylene Pipes

Polybutylene pipes, once hailed as the “pipe of the future,” have become a problem for many homeowners due to their tendency to leak and cause water damage. If your home was built between 1978 and 1995, you might have these problematic pipes lurking in your walls. In the video above, This Old House plumbing and heating expert Richard Trethewey demonstrates how to replace polybutylene pipes with a more reliable CPVC system.

What Are Polybutylene Pipes?

Polybutylene pipes are typically gray, blue, or black in color. This material is flexible and usually joined with metal or plastic mechanical fittings. These pipes were initially praised for their low cost and ease of installation. However, they have proven to be unreliable and prone to failure. The pipes often have a characteristic “Qest” or “PB” marking on them. If you’re unsure whether your home has polybutylene pipes, consult a professional plumber for an inspection.

Why Do Polybutylene Pipes Need Replacement?

Polybutylene pipes are susceptible to degradation from chlorine and other oxidants in public water systems. This degradation can cause the pipes to become brittle, leading to cracks, splits, and leaks. The potential for water damage and mold growth makes replacing these pipes a priority for many homeowners.

Preparing for Pipe Replacement

Before beginning the replacement process, prepare your home and gather the necessary tools and materials.

Tools and Materials

To replace polybutylene pipes, you’ll need the following:

• Adjustable wrench
• Bucket for catching water
• CPVC pipes and fittings
• CPVC primer and cement
• Drywall saw
• Pipe wrench
• Propane torch
• PVC pipe cutter
• Tape measure
• Teflon tape

Replacing Polybutylene Pipes With CPVC Pipes

Replacing polybutylene pipes with CPVC is a multi-step process that requires attention to detail and proper technique. It involves removing the old polybutylene pipes, installing new CPVC pipes, and connecting them to existing fixtures. The process can be complex, so you need an advanced understanding of plumbing to handle the job yourself. Otherwise, we recommend leaving it to a professional plumber.

Removing Old Pipes

Removing the old polybutylene pipes is the first step in the replacement process. Follow these steps to ensure a clean and efficient removal:

1. Turn off the main water supply to the house. This prevents any water flow while you work on removing the pipes.
2. Use a plastic pipe cutter to carefully cut and remove the existing polybutylene pipes. Ensure that the cuts are clean and straight to avoid any complications during the replacement process.
3. Carefully remove any remaining fittings or connections that hold the polybutylene pipes in place. Use a pipe wrench as needed.

Installing CPVC Pipes

CPVC (chlorinated polyvinyl chloride) is an excellent replacement for polybutylene pipes. It’s durable, resistant to corrosion, and approved for both hot and cold water use. Follow these steps for installation:

1. Measure and cut CPVC pipes to fit the existing layout of your home’s plumbing system.
2. Apply CPVC primer to the pipe ends and fittings to prepare the surfaces for cement. The primer cleans and softens the pipe surfaces to ensure a secure bond.
3. Apply CPVC cement evenly and join the pipes and fittings. Ensure complete coverage to avoid leaks.
4. Hold the connections firmly for a few seconds to ensure a strong bond. Allow some time for the cement to set before turning the water back on.

Connecting to Existing Fixtures

When connecting CPVC pipes to existing fixtures, such as faucets, showers, and toilets, you may need to use transition fittings. These fittings help create a secure connection between different types of materials (such as CPVC to brass or copper).

In the video, Trethewey demonstrates how to connect CPVC to a brass shower valve using a female adapter and a threaded CPVC adapter. Use Teflon tape on threaded connections to prevent leaks. Carefully tighten the fittings using an adjustable wrench, but avoid overtightening, which could damage the fittings.

Common Challenges and Solutions With a CPVC Pipe Installation

Replacing polybutylene pipes can present some challenges. Here are some common issues and how to address them.

Dealing With Water-Filled Pipes

Even after turning off the main water supply, some water may remain in the pipes. Keep a bucket handy to catch any residual water when cutting pipes. Use a towel to soak up any remaining moisture. Ensure the area is dry before proceeding with the installation of new pipes.

Working in Tight Spaces

Crawl spaces and wall cavities can be challenging to work in. Use flexible CPVC pipes or create access points in walls and ceilings as needed to reach all areas of your plumbing system. Enlist the help of a professional plumber to handle areas that are particularly difficult to access.

Connecting Materials

When transitioning from CPVC to metal fixtures or pipes, use appropriate transition fittings to ensure a secure, leak-free connection. These fittings are designed to accommodate the different expansion and contraction rates of the materials to prevent leaks.

Soldering Challenges

When replacing polybutylene pipes connected to copper pipes, you may need to solder them. Handle the propane torch with care and ensure all joints are clean and dry before soldering. Soldering provides a durable and secure connection between different types of pipes.

Navigating Building Codes

Ensure that the replacement process adheres to local building codes and regulations. Some areas may have specific requirements or permits needed for plumbing work. Consulting with a professional plumber or the local building department can help ensure compliance.

Benefits of CPVC Replacement

Replacing polybutylene pipes with CPVC offers several advantages:

• Improved water quality: CPVC pipes don’t leach chemicals into the water, ensuring clean and safe drinking water for your household.
• Increased durability and longevity: CPVC pipes are resistant to corrosion, scaling, and chlorine. This means fewer repairs and a longer lifespan for your plumbing system.
• Reduced risk of leaks and water damage: CPVC’s robust nature minimizes the likelihood of leaks, which can cause significant water damage and mold growth in your home.
• Potential increase in home value: Modernizing your home’s plumbing system with reliable CPVC pipes can make it more attractive to potential buyers.

Maintenance and Care for CPVC Pipes

While CPVC pipes are more reliable than polybutylene, maintenance can extend their lifespan and prevent issues. Regular maintenance and inspections help ensure the longevity and efficiency of your new plumbing system.

Regular Inspections

Periodically check visible pipes for signs of damage or leaks. Pay attention to water pressure changes, which could indicate a problem. Inspect joints and connections for any signs of wear or corrosion. Early detection can prevent minor issues from becoming major problems.

Water Treatment

Maintain appropriate water chemistry, especially if you have a water softener or treatment system, to prevent damage to your CPVC pipes. Hard water can cause scale buildup inside pipes, reducing water flow and increasing the risk of leaks. Use water treatment solutions that are compatible with CPVC to ensure their longevity.

Avoiding Chemical Damage

Be cautious with chemical drain cleaners, as some can be harmful to CPVC pipes. We recommend opting for mechanical methods or enzyme-based cleaners when possible. Mechanical methods, such as using a plunger or drain snake, can effectively clear clogs without damaging the pipes.