Why is my flat suffering water hammer?

WIAWSNB

Lorian said:

I agree and ultimately the pressure wave being created is bouncing back off something.

The OP could possibly get a suppressor soldered in where their supply enters their property but it's likely easier and cheaper to do it at the source of the rapid valve shutting. 

Making sure pipes are properly secured in clips can help a little but won't fix it in my experience.

Like I said though turning the stopcocks off just a tiny amount can sometimes be enough.

Yeah - the miscreant neighbours'... :-)

Mr R, would it be easy to fit a shock-arrestor just after your SC at ground level? That would hopefully capture any shock from the other supplies, before it travels up to your flat. 

(Are you sure that every flat has its own individual supply...?)

twopenny

There used to be a horrible annoying noise from en suite loo being flushed in both mine and the linked bungalow, both have the same pipe work.

When I had a new bathroom fitted elsewhere and something changed and mine stopped making the noise.
Tracked it down to the stopcock being opened a tad more.

I told my neighbour and she adjusted hers.

Result, peace 🙂

I had fiddled with the stopcock after advice on here but I was probably too gentle with it. Just didn't hit the spot.
Always worth a try but perhaps your neighbour needs to do it as well.

Mr_Rumbold

I have been discussing this with the managing company of the flats and plan later to post a picture of the common pipework here for opinion.

Thanks to the respondents so far.

grumpy_codger

I don't think that general plan matters. Water flowing to some flat flows through the shared pipe as well. Water hammer happens when all this big volume of water abruptly stops. The only factors that matters is how far from that flat and from your flat the flow splits and how elastic the pipes are . I'm pretty sure plastic pipes are less prone to water hammer than steel pipes; copper pipes are somewhere in the middle.

Mr_Rumbold

Both flats below mine report water hammer, so I do wonder if this problem is to do with one of the flats specifically, or with the common plumbing illustrated below:



If anyone seeing this picture has any ideas as to the cause of this water hammer issue, do please say what you think. Whatever the case, a plumber is needed ...

WIAWSNB

It's no great surprise that one flat's actions can affect the others, given how they share the same incoming mains supply.
Any idea what the supply pressure is like? When you use the kitchen cold, how 'forceful' is it?
If the incoming supply pressure is 'excessive', say more that 3bar, then individual PRVs on each supply - very simple to fit on each pipe just beyond the drain-cocks - could be enough to sort it, as well as easing the stress on each flat's system. If that didn't work, then adding a shock arrestor too should do so. Perhaps try adding one to each supply at a time - see if only the miscreant flat's will sort it.