What is causing water hammer in my flat?

[Mr Gwent]

Hello

I wonder can anyone shed any light on what is becoming an annoying problem?

I had a new stopcock installed in my second floor flat a year ago. This was intended to stop water hammer which had been taking place. However, recently the water hammer has returned and from what I can tell it occurs when water is used in the flat below mine, and possibly in other flats as well. The noise is a banging or crunching of metal sound and it can be quite loud.

But, I cannot work out is why this is happening, and this is where I seek advice. Could the water hammer, if that is what it is, be the result of a vibration in the pipes because of water usage, water pressure or an air gap? If this is so, where might it be occurring?

Water in my flat is delivered via a dedicated pipe which rises through the building. This pipe is, as far as I know, isolated from the other flats which have their own respective pipes. Whether these pipes branch from a common supply which connects to the mains, or if they are connected directly to the mains, is not something I know.

Any advise would be appreciated ...

Thanks

Mr Gwent.

 

[Maryplumb]

How old is the block of flats? What makes you think you have a separate riser? That should mean less noise from neighbours and exact point of connection below is not likely to make much difference.
Hearing neighbours turning off taps is common but that's a brief sound. Banging in pipes more serious as you've
experienced before but crunching metal sound?