Pipes rattling - water hammer?

pledgeX

martinthebandit wrote: »

To be honest it doesn't sound like its water hammer to me, from what you have described it sounds far more like air is trapped somewhere in your waste system.

If it only happens from one particular sink I would be looking at the waste pipe route from that sink and seeing if I could eliminate anywhere that may be causing air to bubble up back against the water going down by seeing if I could secure, or reroute, it better.

I seriously doubt that there would be enough pressure in a sink waste to cause water hammer.

It doesn't happen only from one sink, but it's definitely a lot worse from one sink. As said above, I can't get access to the pipes without pulling down walls. Anything else I could try to do?

ariba10 wrote: »

Have you tried turning the stopcock until it is only open half a turn as I suggested earlier?

(Humour me please)

I can't right now as I'm at work. I'll try do it over lunch, or if not this evening though and report back.

Thanks for all your help so far people

martinthebandit

pledgeX wrote: »

It doesn't happen only from one sink, but it's definitely a lot worse from one sink. As said above, I can't get access to the pipes without pulling down walls. Anything else I could try to do?

Hmmm if it happens with all your sinks, and toilet, then it might be that your vent pipe is blocked.

But it sounds far more as though you are going to have to identify exactly what is knocking onto what and then fix it properly.

I suspect you are going to need to listen against a lot of walls while water is draining to try and pinpoint it.

ormus

i assume we are talking plastic waste pipes here?

rafal.d

It is very simple.
You need to secure waste pipes to the wall/ ceiling

pledgeX

Thanks again for all the replies

I tried turning the stopcock to half a turn as you suggested ariba10. Was still exactly the same. I also turned it off completely and opened all the taps in the house in the hope that it might clear some air, but it didn't make a difference.

I then pulled off the bath panel and tried to listen out for where the noise is coming from. I'm almost certain now that it is the soil/waste pipe. I took a picture of it:



Sorry for the poor quality, but like I said it's hard to get to! So the vertical grey pipe runs up into the loft and out the roof, then runs between the wall downstairs out the bottom of the house. The pipe joining it from the left is from the toilet, the one joining from the right is the bath, and about a foot higher up just out of shot is where the sink joins.

I gave it a bit of a wobble and it's pretty rigid, there's not really any flex in it at all, although if I really give it a shake I can hear a creaking similar to that heard when the water drains. The joins all seem fairly secure as well.

I could try securing it as people mention but I'm not sure it'll make much of a difference. As like I said it is fairly rigid as it is. The other problem is access. In that photo I can't even reach the piping. That photo is taken at arms length as far in as I can get the camera. There's a bath and a toilet in the way so there's no way I can get to the pipe to fasten it.

I may be able to do something with it in the loft, but the roof is only about 30cm high at that point so access is a nightmare, and I'm not sure how good a single fastening point would do on a 6-7m long pipe!

Is there anything else I can try?

pineapple

I live in a small community and all of us were experiencing some problems. Not exactly water hammer but an awful noise and you could feel the pipes vibrating - not necessarily after running water in your own home. It was fixed when Yorkshire Water fitted a pressure reducing valve up the lane. Just to say check that neighbours aren't having problems too.

Canucklehead

Hi,

As you have discovered it's the waste pipe.

Nothing to do with water supply to the bathroom at all.

You will drive yourself insane and dismantle the bathroom to find the source, as it's most likely to be the 110mm soil pipe touching the joist.

Lack of care all round during the build IMO.

GSR.

MonkeySaving?

LOL at all these experts! Have you never head of Mr Pipes ala Ghostwatch fame?

keystone

Oh, an INTERNAL plastic stack . They're often horribly noisy. 1970s "thrown together" property? May be due to water simply dripping and hitting something like an angled bit of pipe. But as CH correctly says its probably binding on some timberwork somewhere and thermal movement is causing it to judder against the timber. Alternatively you have inadequate expansion joints in the stack. You may be able cut a section of pipe out, replacing it with the section slightly shortened, and a couple of slip couplings. These have rubber seals at the ends so the pipe can move - hopefully silently.

Cheers

ormus

as above.
also some of those pipes look very close together. try inserting some rubber/spongey/foamy type stuff between em.