Intermittent leak from tap pipework

Mistermeaner

Hi all; want to share experience that’s got me stumped!

Long story short; bought a 3 bed 1 Bath house 18months who. Knocked seven bells out of it, 2 storey extension loft conversion added a new bathroom in loft garage conversion new downstairs wetroom kitchen utility , new megaflow and mains water feed etc etc

Only room we haven’t touched is the existing first floor bathroom although we know it was done by Previous owners in last 5 years

Twice in the last month (weeks after completing the work) we have had a massive leak from in the wall behind where the original bathroom is, from the pipes that feed the bath tap.

Luckily (ish) these pipes are in the external porch ceiling so the water mostly cascades down the outside of the front door.

I’m not talking drips I mean full on gushing water

What’s so strange is it’s only happened twice, and not when the bath was in use.

The first time we weren’t sure where it came from as water came out everywhere in the porch - we then ripped down the porch ceiling and exposed (partially ) the bathroom pipes (inc waste) - we thought the waste may have got blocked and backed up ....

Having left the porch ceiling exposed to let everything dry out it happened again tonight - out of the blue another gushing torrent - as the pipes were exposed I could clearly see it was coming from the bath tap pipes that disappear up through the porch ceiling / bath room floor into a false wall that forms the bath enclosure

I turned on a couple of downstairs taps that clearly relieved the pressure, the torrent stopped and when I turned those taps off again the leak stayed stopped.

It’s maddening that it’s so extreme on / off and no obvious cause

On both occasions it’s been night time , circa 10pm (when I think pressure is higher) , both times it been after kids are in bed, so we’ve had 3/4 baths / showers / dinner / dishwasher / washing machine all variously going (there is 5 of us living here)

Clearly all the work we have had done has messed around with the pressures in the water system ; particularly the new main, megaflow and loft bathroom (albeit the loft bathroom has its own dedicated feeds from the new main)

I was just wondering what may be going on with the fittings on the bath tap that could blow intermittently in such a fashion but be fine minutes later - and I mean not even a drip for days !

We’re just debating whether to pull apart the bathroom or the porch ceiling (even more) to get proper sight of the pipes but what on Earth sort of connection could be so temperamental as to be a gushing torrent one second and nothing the next .... as far as we can see there is copper pipes with white push fits in the bathroom floor and metal coated flexies into the back of the tap - the 3ft between there where the leak is happening we can’t see


Nb noticed we get a fair amount of pipe hammer in that room. Eg turn off the basin tap and the toilet ‘clunks’

Any ideas people ?

southcoastrgi

Where does the safety pipework for the megaflow go to, I'd be looking at that first

Mistermeaner

Hi thanks ; mega flow is in the utility (was garage) on ground floor, it goes straight out of external wall into a drain. The leak is in the ceiling of the ground floor (or the floor of the 1st storey)... ie 1 storey above the megaflow

Had plumber over tonight and removed the tap and associated 4ft of pipe for each of hot and cold, this took us back to where already exposed piping is ( the leak could only have come from the removed 4ft and tap)

It took a fair bit of yanking and twisting to get it out but came out intact , nothing visually up with it... a mix of copper and plastic with push fit 90s. Joined flexies by the tap. We pressure tested it to 12bar and not a drop leaked, messed with the tap under pressure kicked it around everything ... no leak

Absolutely mystified as it must be this section of pipe that leaked- there is nothing else there- the wall insulation where this pipe was is soaking wet, the insulation just above is dry

Me, the plumber , our buillder all mystified

The feeds are now capped and we!!!8217;re using the rest of the house fine, will give it a month before reinstating just on off chance it occurs again but can!!!8217;t see how it can

Nb turns out we have a pressure regulator on the incoming main that limits us to 3bar (apparently to protect the megaflow) so external pressure shouldn!!!8217;t matter

Nbb the pipe knock has stopped now the bath tap is gone ... maybe that was something do with it ???