Pipe wet but not where there joint?

[alan0259]

A little baffled at this one...

I’ve almost finished re-doing all my downstairs cloakroom and I have one 15mm copper pipe that is wet to the touch underneath the pipe. This pipe is the hot water feed to the room (not plumbed the sink in to run water yet, the pipe is cold and it’s isolated at the end where the basin goes), the wet pipe is at the other side of room where it comes in from another room.

There’s an existing soldered elbow to the left of this pipe, this feels drys

To the right of this pipe there’s a new JG push fit isolation valve that I’ve fit myself, and this feels dry.

It could have always been like this and I’ve just never noticed, weird how there’s no drips of water on the floor...

Can copper pipes leak from the solid lengths of pipe themselves somehow?

It’s about 1 inch above the floor and runs along a wall so seeing underneath it is near impossible...

 

[CBW]

It could be condensation.

 

[alan0259]

It could be condensation.

Just been googling and seen this.

The cold pipe is right above it though and this is dry.

And it’s doing it when the house isn’t even that cold.

Any sure way of ruling this out?

 

[Harry Bloomfield]

Yes, new pipe can have pin holes in it..

Wrap toilet tissue round the pipe, it will help localise where the leak is, if there is one.

 

[Newboy]

Can copper pipes leak from the solid lengths of pipe themselves somehow?

Occasionally you can get pin-holing in copper tube.

On some occasions I've seen it look and feel like condensation. Dry the pipe with tissue and then get some blue/green paper towel and wrap it along the pipe at strategic points. The darker colour will show up any moisture very clearly.

 

[terryplumb]

A small mirror can be useful ,and a torch ,to see below / behind pipe. Pin hole leaks in copper pipes that are corroding from inside start as miniscule weep.

 

[bernardgreen]

A good way to find leaks is tissue paper with lines drawn on it with water soluable ink. If the paper gets wet then the ink runs and the lines become smudged. Even if the tissue dries the evidence of having been wet is still there.