The House Detective: by Barry Stone, Certified Home Inspector
Dear Barry: Our home is only 20 years old, and we just had a pinhole leak in a copper pipe above our dining room. Our insurance will pay to repair all of the damage, but we’re worried about this happening again. Next time the damage could be worse. We’ve heard that leaky pipes can be repaired by coating the insides with epoxy. Is this a good idea, or would you recommend installing brand new pipes throughout the house? Camille
Dear Camille: Coating leaky pipes with epoxy is a repair method that has been gaining popularity in the United States since the 1990s. Its use is still subject to debate among plumbing professionals, but many plumbing systems where epoxy coating has been used have withstood the test of time.
Most people have probably never heard of this method for repairing leaking pipes, so here are the basics. The procedure for lining water pipes with epoxy involves the following four steps:
1) Preparation: All valves, stops, fixtures, and water heaters must be disconnected to prevent them from being damaged by the epoxy and to enable the entire piping system to be drained of water. Hot air is then blown through the pipes to dry them completely. The pipes must be totally dry to enable the epoxy to adhere.
2) Cleaning: The interior surfaces of the pipes are then scoured of corrosion and scale by means of sandblasting. This is done by forcefully blowing abrasives through the pipes.
3) Coating: Epoxy is blown through the pipes to coat the entire system. This seals all joints and prevents further corrosion of the metal. Excess epoxy is then blown out of the pipes and steam is injected to cure the new synthetic coating.
4) Reconnection: All of the valves, stops, fixtures, and the water heater are reinstalled.
The total cost for this process is approximately 80 to 85 percent of the cost to replace all of the pipes in the building. On the positive side, the epoxy method is much less intrusive than repiping because no holes are cut into walls and floors, as would be done if new pipes were installed.
Expected longevity is also an important consideration. Epoxy coatings are usually guaranteed for approximately 10 years, which is much less than the life expectancy for new pipes. If you plan to stay in your home for many years, this would be a significant consideration. If you go with epoxy, be sure to research the companies you may hire. Find a contractor who has been doing this for many years and who has a reputation for high quality work.