Hi, I've read a bunch of question and replies but none seem to answer my question, so here goes:

I have the banging in the pipes problem, and I was assured by friends/family that this is fine, it's just old pipes. (I rent a flat in an apartment building so it's not like I can fix it.)
What I want to know is, just last night there started this rhythmic banging/tapping noise in the floor below my bedroom. It's only in that part of the apartment that I can hear it. It starts, goes for about a minute, stops and then starts again a minute later. I've lived here 2+ months and have not heard it before. I read a few answers on this website saying it could be vibrating pipes, but what I want to know, is it dangerous? It sounds like they're going to burst! But of course, the banging scared me at first too. Is this just another sound to learn to ignore? Or should I be mentioning this to someone?
Thanks so much in advance,
Ella.

"just last night there started this rhythmic banging/tapping noise in the floor below my bedroom. it's only in that part of the apartment that i can hear it. it starts, goes for about a minute, stops and then starts again a minute later."

This doesn't sound like water hammer. It sounds more like the pipes are expanding and contracting in the cold weather. Knocking, popping, creaking and crackling pipes are a common complaint, especially in colder weather. I can tell you what's happening and take the mystery out of it but you're not going to like the repair. When a draw is made on a hot water line the line expands against a pipe strap next to a stud and when you drain hot water from your tub or shower it goes into a chase that is a little cooler then room temperature. The heat expands the pipe causing it to rub against the stud to which it is pipe strapped. This is the sound you hear. As it cools it contracts and the noise is heard again. To repair it you must tear open the walls and locate the pipe strap that's causing the problem and shim it tight. Most people when they learn what causes it just elect to live with it. Regards, Tom

Next time you hear the noise, go look in your toilet to see if it is running.