Ask Me Help Desk - Strange noises!

Hi! I have a real mystery on my hands. Let me give you some back ground: My house was built in 1969 and has copper supply and drain lines.

When using the upstairs master bathroom (either faucet, toilet, or shower) you hear a very distinct banging or knocking in what I think are the drain pipes during and for 15-20 minutes AFTER you turn off the water. The noise seems to have become louder in the past several months. The noise sounds like someone rapping a wooden spoon on the pipe and/or the irregular sound of dripping water. There are two distinct sounds. The dripping water sound is odd because it is irregular. It might go: drip.drip... drip... drip.drip.drip. etc. Same with the knocking sound.

If you go into the basement and place your ear against the copper stack about 8" above where it meets the cast iron, you can actually feel the vibration against your head.

I've been unable to locate any leaks or wet spots on the ceiling or walls. But it is driving me CRAZY! Like I said, over the past few months it has gotten louder and it seems to be lasting longer... Please help me!

Thanks,

Joe

I need a few more details Ace,

This sound, how loud is it? How fast is the vibration? Is the noise more of a rap, a bang or a howl? Do me a favor. Next time the noise starts try to localize it. Check the toilet tanks for noise. Tell me where it's the loudest. Good luck, Tom

Tom,

The sound is pretty loud - I would equate it to slightly quiter than a normal knock on a door or the sound of someone gently rapping their hand on the other side of a wall. The sound appears to be coming from inside the wall AND ceiling. From different locations at different times during the same incident. The sound from the wall would be at about head level or above - standing next to the wet wall on the first floor of the house. Again, standing on the first floor, the sound also seems to come from the ceiling in the area that is immediately below the shower/bathroom. It is most noticeable when someone takes a shower and appears to be most noticeable when using hot water, but it still occurs when using only cold water.

When standing in the 2nd flr bathroom, the sound appears mainly to be coming from inside the wall at about knee height or below.

The sound isn't as much of a vibration as it is a knocking or rapping and also dripping sound. The rate is about one sound per 1/2 second and then will slow to one sound every 15 seconds and then vary back and forth from there. What confuses me, is if it were dripping water I would expect it to be a fast rate and slowly taper off. Instead, the sound is fast then slow then fast again.

The vibration I described in my fist post is somewhat misleading - what I feel when I press my ear against the stack is similar to what I would expect to feel if someone were tapping the stack in the attic with a wooden spoon. It's not violent, but definitely noticeable.

I checked the toilet tanks for noise - they are all quiet. It is the loudest on the first floor where the sound seems to be coming from behind the wet wall at about head level.

I hope this helps and I really appreciate you taking the time to try and figure this out!

Joe aka Ace

OK Joe
I think I can take the mystery out of this for you. At first I thought you had "seat chatter" but now that you get a little bit more descriptive the sound like pipes expanding and contracting against the pipe straps and the studs or rafters.
This is what clued me in,"It is most noticible when someone takes a shower and appears to be most noticable when using hot water, but it still occurs when using only cold water."
When hot water goes through a cold pipe the pipe expands. When it cools off it contracts. This expansion is what you hear. It won't hurt anything and to track it down and shim the pipes means opening up the drywall and going hunting. I hope explaining what's going down will be enough but if you really want to fix it you'll have to open up the drywall where the sound's the loudest and shim the pipe between the pipe strap and the stud and that's not going to guarantee that you have every one. Good luck, Tom

Thanks Tom - in reading your answer, it made me think of another clue - the sound seems to be louder in the winter. I live in Cincinnati, OH (Go Bengals) and we have pretty cold winters here. Since the noise also seems to be more pronounced in the winter, that would support your analysis since the main stack is relatively close to the outside wall and the pipe would naturally be colder in the winter, which would make sense that the sound appers to be louder when it is cold outside and hot water is being used.

Is is safe to assume that this is not a "dangerous" problem, i.e. its not going to suddenly start leaking, but is more of an annoyance?

We plan on remodeling the 1st flr. Laundry room in the future so I may expand that to replacing the drywall on one side so I can track down this stupid sound!

Thanks for your help!

This is quite safe and will not harm anythig except your nerves. Cheers, Tom

Quote:

Originally Posted by speedball1

This is quite safe and will not harm anythig except your nerves. cheers, Tom

I live in a 3 story home and have the same issue with the upstairs bathroom. It freaked me out when I first moved in, but like yourself, I've noticed it is worse in the winter and something I've just learned to live with.

I was worried by house was going to collapse (based on all the horrible creaking) but after no signs of rot, mold, moisture or cracks in the drywall... I figure I should just learn to accept this little quirk.

I have some strange noise in my ceilings in my house. It sounds like a loose bearing or electrical buzz. Does anyone experience the same thing, or have an idea what it could be. I willing to pay something for the right answer. Thanks in advance