Bathroom Pipes - Loud Tapping Sounds at Night, Please Help!

[amonson1984]

I live in a first floor apartment in Texas. Beginning about a month ago, in the middle of the night (1-2 AM), loud tapping noises have been coming from inside the wall above my bathroom sink. It sounds like a hammer tapping on metal and is loud enough to wake me up. I assumed it was some issue with bathroom pipes. The sounds are anywhere from one to five seconds apart and will only disappear after about 30 seconds of running the hot water in the bathroom sink. But the sound usually comes back two or three more times in the middle of the night. It does not happen during the day.

I'd like to bring the issue to the apartment complex's maintenance crew, but they are mostly inept and without a reasonable idea about what's causing the tapping, I'm afraid nothing will get done to fix the problem, especially since a portion of my bathroom wall would have to be torn out just to get to the pipes. Not to mention that it only happens at night when maintenance clearly can't come over to hear it.

Does anyone have any advice about how to approach the situation? I'd like to make a few suggestions to maintenance so they will be able to help quickly and efficiently.

 

[SlowDrip]

Since it is an apartment, it is possible that someone running water somewhere else in the complex is causing suction on your pipes which makes them vibrate.

 

[amonson1984]

That could be a possibility, but I'm still most confused by the fact that it only happens at night. I've never heard the sound during the day time. Could it have something to do with the pipes expanding/contracting from cold nights? Now that I think about it, this never happened during the summer...

 

[SlowDrip]

It could possibly be from contracting pipes in the cold, especially since you say running hot water makes it stop. If so, the pipe is improperly insulated. Is it on an outside wall?

 

[amonson1984]

No, the pipes are all between the walls. No access panels or anything, so maintenance would have to tear a chunk out of the wall to get a look. That's another story.

 

[SlowDrip]

Ah, by outside wall I mean is the wall that contains the pipe towards the outside of the building, or is there another room on the other side?

 

[amonson1984]

Oh - it is on an outside wall, yes. It's directly above a series of water/electricity meters and the building's cable hookups.

 

[SlowDrip]

That makes it more likely to be an improperly insulated pipe. I suppose it is also possible that something from one of the meters or cable boxes is knocking on the pipe as well if the pipe is exposed.