Pipes can make knocking and other sounds due to water hammer, a phenomenon that occurs when a valve is closed in a high-pressure water line. Loose pipes and fittings, and expansion of copper lines, can cause noise in your plumbing as well. If you have knocking pipes, you can take steps to reduce the noise and settle your nerves.
Silencing Knocking Pipes
Pipes can make knocking and other sounds due to water hammer, a phenomenon that occurs when a valve is closed in a high-pressure water line. Loose pipes and fittings, and expansion of copper lines, can cause noise in your plumbing as well. If you have knocking pipes, you can take steps to reduce the noise and settle your nerves.
How to Fix Knocking Pipes
Water moves quickly through narrow pipes. Upon closing a valve, such as a sink faucet, it has nowhere to go; the abrupt stop causes a loud thud, which is often loud enough to be heard throughout your entire home. And if not corrected, it can damage pipe connections and joints. Your plumbing has air chambers to create cushions that buffer the shock of water slamming against piping. You can eliminate knocking pipes by:
- Turning off the main water supply valve.
- Opening the faucet at the highest point in your house.
- Turning on the lowest faucet to drain the water (air will replace it).
- Shutting off the lowest faucet and reopening the main valve.
- Air will push out of water lines, exit faucets in a sputter, and remain in the air chambers to stop water hammer.
Stopping Noise in Copper Pipes
Copper pipes expand when hot water is running, and contract when cooling, creating ticking and creaking sounds. To reduce the noise, you can try turning down your water heater thermostat. If this doesn’t work, or you’re unable to turn down the hot water heater, there are other methods you can try.
Soundproof Pipes with Insulating Material
One way to deal with pipe noise is to use a soundproofing wrap. First, make sure the pipe is clean and then measure its length to determine how much wrapping to use. Cut the insulation with a utility knife, to a size that matches the length of pipe you measured, and then begin wrapping the pipe starting at one end and working your way down its length.
Wrapping pipe can also protect it against freezing in addition to deadening the noise. If you are wrapping hot water pipes, make sure the insulating material is rated to withstand hot temperatures. Otherwise, the material may melt onto the pipe.
If using spray-on foam insulation, make sure the pipe is secure and spray a coating on. Wait until this coat is dry before spraying on another coat of insulation. This process can be repeated until you feel the pipe is adequately coated. Only use spray-on coatings for pipes that do not move, as hardened spray-on foam can chip away due to repeated contact with studs and other surfaces.
Fix Loose Pipes
Water pressure can cause a pipe to vibrate if it is loosely attached. The pipe can be secured with straps. If any mounting straps present have loosened, the pipe can vibrate against framing and other building elements. Tighten the straps to secure the pipe; most have either nail-in hooks or hangers that, when tightly secured, prevent the pipe from moving. Cushioned pipe hanger brackets can be secured to studs using wood screws and a screwdriver (for existing homes, this requires opening the wall).
Fill the Wall Cavity
If you can’t access the pipe directly, another method to reduce noise from water pipes is to fill the wall cavity surrounding the pipe. Choose a safe material, such as that made of recycled cotton. To proceed, follow the instructions included with the product. You’ll need to measure the area to cover, cut the material to size, and press it into place; friction will then hold the material tight so pipe noise is dampened.
Contact Express Plumbing Heating & Air
You could also adjust the water pressure if it’s too high and causing knocking pipes. But if none of the above tips work for you, or you’re not comfortable attempting a DIY fix, our trained, certified plumbers can help. We specialize in all types of pipe repair and offer specials, financing, and protection plans for our customers in the Treasure Valley. Call (208) 398-0309 to request a service appointment.
