Overflow pipe leads into wall but can't be seen exiting outside the house

[Silvan]

Hi folks

The overflow pipe from the cold water tank in my roof space can be seen going into the wall (see picture) but it cannot be seen exiting on the outside of the house.

Why is it like this? Could it be connected to a drain somewhere with the wall cavity? Could some cowboy plumbers have been doing stuff in the house before I bought it?

The house was built about 50 years ago, of cavity wall construction, block inside and out. Will the walls in the roof space also be cavity walls, or might they be single thickness?

David

 

[Jajodu]

Is it connected to somewhere near the top of your cold water tank? It looks like an overflow pipe.

 

[Silvan]

It comes out the bottom of the tank, connected to a vertical tube inside the tank. If the ball cock fails and the tank keeps filling up the water level rises over the top over that vertical pipe and spills into it. From there it is supposed to flow through that pipe and exit outside the building I think.

 

[Jajodu]

In that case force an overflow and see where the water exits outside.

 

[Silvan]

There isn't a redundant pipe sticking out of the house anywhere. There is one for the central heater header tank and no others.

A couple of weeks ago the ballcock on the tank failed to shut off the water supply. Water spilled over into the overflow pipe, which leaked at a bend which I think should have been sealed up using a solvent join. So on two bits of evidence it looks like a plumber was not doing a good job when fitting the overflow (i.e. didn't use solvent to seal the pipe joint, and didn't cut through a wall to drain the overflow outside the house). There were some other examples of poor plumbing which we found when I had a new boiler put in a few years ago.

Water flooded the top side of a ceiling and dripped out of an electrical ceiling rose into the bathroom, which I noticed quickly so there wasn't any serious damage. I'm just trying to figure out what to do to with the overflow.

I will try pouring a litre or two of water into the overflow pipe and see what happens.

 

[Jajodu]

Normally it would exit the wall on the outside, that way it would be noticed but not do any damage. Can't believe it was left like that!

 

[Koolpc]

You could chip out the cement around the pipe and see if it goes anywhere...

 

[Silvan]

Sorry everyone, the overflow pipe does lead out of the wall, but it it isn't easy to spot. I took the suggestion to tip some water down the overflow, then went outside and there was a damp patch on my (very white) roughcast. I still couldn't see the pipe it is flush with the wall not sticking out. But by going into my neighbors garden with a pair of binoculars I could see that it is there, unblocked and of the correct diameter.

So my only task now is to repair the leak which is present in the pipe as it make its way from the tank to the wall. I don't want to do anything affecting the tank as it is an old fibreglass thing which TBH seems a bit flimsy. Can I repair the leaky joints (picture attached) somehow with something like: fiberglass resin tape, epoxy putty, repair tape.

Given that I have been in the house over 20 years without any problems other than the recent one even if it still leaked a bit it would be okay. I could extend the pipe outside the house and it would drip onto a flat extension roof and we would hear it. I might even make a small hole in the ceiling so that a little drip could come through and drip onto the floor of the room below which is a bathroom with a vinyl floor covering.

And when away on holiday I could shut off the water that feeds the tank.

 

[Jajodu]

Cut that pipe and replace with new, it looks like solvent weld joints

 

[Koolpc]

Now you know why it was cut short!