Shaking/vibrating pipe under sons floor, any help? Is piglet John still aròund?

[Dilemmaleeds20]

Hi

Since last week i have been hearing a random vibrating/shaking/shuddery noise. It occurs for about ten minutes, stops then can start again within 15/20 mins. Its not massively loud, but if I am sat in front room I can hear it
Followed the noise earlier and its definitely under my sons bedroom floorboards, near his radiator.
Any idea what this could be?
Its not water being switched on thats causing it i dont think, as we were all in bed the other night and i came down to check the doors were locked and heard it.
Could possibly be shortly after toilet is being flushed, but im pretty certain its just on its own as I havent noticed a pattern yet.

Any help please?

Have you tried bleeding the radiator?

No I haven't, it didnt even occur to me it could be trapped air. I was thinking maybe a loose pipe, will try it and see. Thanks

Does it match at all to when you have the heating on / running hot water? Had it just started recently? Bleeding the radiators is always a good idea sporadically, but this likely won’t fix it. Could be a pipe has worked lose from its clip under the floorboards. Could be sludge in the system getting pushed around. Lots of things. If you can isolate the noise to a specific spot, can you get access? Pulling the carpet back and lifting a floorboard or two won’t be too hard / disruptive.

Hi Mike
Thanks for the reply. Yes i can isolate the noise now to a specific spot. I have bled all radiators now and havent heard it since, no air came out of my sons bedroom radiator however the bathroom radiator did have alot of air in it.

I first heard this noise about 4 days ago and then nothing again until today, so not convinced its fixed from the bleeding radiators yet as it did stop and then come back. Will see how next few days go and look under floorboards if it starts again

Thanks

Will also check the hot water and heating if it does start again and see if it matches.

We had this when loo flushed but it is wasn't the loo making the noise it was a pipe at other end of room
Turned out it was the water valve in the ball cock (mechanism that goes up and down) that had degraded/worn out. We replaced the thing that goes up and down (whole mechanism ) and noise stopped
You can test this theory by running a tap, noise usually stops then too, but returns when tap goes off again.
Also stopped when loo cistern is full up again

It's the pressure building up in the water pipe I think that makes the shuddering noise

Ours was like the whole house was shaking!!

If it is water mains related it could be water hammer and you can solve with an arrestor. The noise will come with use of mains water that changes pressure quickly - when a tap is turned off for instance. If it is central heating related then as per above could be a few things. Something to look into as if your pipes are moving then it could weaken joints and cause a failure. That is worst case, and if coming and going I don’t think you’re heading that way at present. Do you know when the system was last flushed? Could be sludge build up but you’d likely notice some of your rads being cold at the bottom too which not sure if you have? The one in your son’s bedroom - is it hot all over or only towards the top? Other thing to consider is vermin - they can sporadically chew at pipes etc which will make a noise. If it’s easy enough to get a floorboard up that’s what I’d do and get visual on it. If you need to see further under you can buy an endoscope for about £20 from screwfix etc which will let you look about 3 metres under the floor. You might even be able to get it down an existing hole or with (carefully) drilling a small hole in a floorboard - make sure no pipes underneath!!!

So the noise has come back as I thought it might.
I cant isolate anything like a tap that is causing it to start, seems to just start randomly at different times of the day.
Did start about 10 mins after we put the heating on though today.
Felt the radiators, they all feel hot at top and bottom but slightly hotter at the top than bottom.
We have had a look under floorboard, this house is about 100 years old now, pipes are sat in joists and noticed one had come out, have put back in and wrapped it to keep it sat so will see how we get on with that 🤞 really appreciate your replys thank you.

We had this when a particular toilet was flushed. The plumber said it was water hammer, can’t remember how it was fixed but didn’t take long or cost much as far as i remember.

Does it only happen when the heating is on?

It wont be hard to pinpoint.

Our house can have this when the boiler is pumping hot water to radiators. The under floor pipes can knock.

Might just be worth trying to bleed it again. If there was air trapped, and it didn't all come out the first time, what's left may well have migrated to the same spot.

Thanks, sounds back again so wasnt the pipe knocked out the joist that was the problem. We didnt take sons bedroom floorboard up because its wooden flooring, we checked in next room right next to sons bedroom wall but now looks like we are gonna have to get his floor up.
Will bleed them again too.
Its driving me mad!

No, it can happen even when heating is off. This is the first time today we have out heating on in months so doesnt make a difference.

OK my 1st thought was a valve rattling as the heating turned on or off but if not heating related then wont be that.

It must only happen then as cold water shuts on or off elsewhere. How is hot water supplied? Is it on an old gravity fed system with a tank in the loft. Is the toilet an old type? A ballvalve may be faulty.

Hot water is supplied through a boiler in the kitchen, boiler is about 3 years old.
We have 2 toilets, upstairs one is about 4 years old, downstairs one is older, over 10 years old and has had issues with refilling so we have turned the water off to that one on Wednesday to see if that helped and havent turned it on since, but noise is still continuing.

Thanks, have bled them again just incase.

But what sort of boiler is it? If its a combi then there will be 6 pipes coming off it. If its a heat only there'll be just 2. Do you have a water cylinder upstairs? Is there a pressure gauge anywhere?

You say you turned off water to downstairs toilet. Are you sure its definitely off? I presume theres a little turn valve under the toilet.

100% combi boiler, counted pipes and checked our guarantee.
Partner says we dont have a water cylinder upstairs, we dont have a pressure gauge either.
Yes definitely off, turned valve under toilet and not flushing/filling up.

So we can rule out hot water. And probably heating but you never know.

So that leaves cold water. Toilets are the only places cold water goes to that aren't controlled by a tap. You have isolated the downstairs toilet so that just leaves the upstairs one. Can you isolate that too for a good while and see if noise stops? I would hazard a guess that theres a problem with that toilet and its randomly filling back up. The pipe in sons room must be loose and is rattling when the fill valve in the loo closes.

We have got a new fill valve for downstairs toilet which we are going to do tomorrow. When thats sorted, i will switch that back on and turn off the upstairs toilet and see how we get on. Will also get sons floor up and try to secure the pipe under there.
Thanks so much for your help, i really really appreciate it.

Id be tempted to take the lid off the cistern of the upstairs loo and have a look and see if anything is going on. Also see if water is running into the pan or if there is any leaks on the back of it. These could all cause the water levels in the cistern to be up and down and could cause the washer in the fill valve to vibrate when it shuts off and you'd normally hear it there rather than anywhere else, but plumbing is a dark art. Its all a case of logic and isolating different parts till you find whats going on.

Also just a quick thought, no showers that are dripping at all?

Sorry only just seen this. We are going to have a good look at both toilets today, i will have a look under cistern.
A few years ago we had a leak under the bath, but as far as we know that was sorted / had stopped, we will have a look under that too as we did leave a small container under there just as a precaution. Shower not dripping that I know of, but again will have a close look today. Funnily enough yesterday morning I thought I heard a small vibrating noise under bathroom floor right inbetween toilet and bath, but thought maybe I was just hearing the pipe again in sons room travelling, but interesting that it could be that.

Possibly unrelated but about 5 years ago the pipes under the bathroom would bang really loud, especially at night, when we changed the flooring, we found the pipes next to each other were making the noise, bought some stuff to put between them and its never done it again.

Will report back later. Thanks again, this is a great help.

Update
Partner turned stopcock off and drained all cold water pipes, filled back up with taps open on Saturday, also fixed downstairs toilet fill valve and the noise/shaking pipes hasnt returned 🤞
Hopefully thats the end of it.
Thanks for your help everyone.