CH pipe - green powder :-(

Our CH is in the utility room of our bungalow. Because the corridor outside is a solid, concrete one, the CH fitter took pipes across the loft, and dropped them down the wall where they disappear into the floor, and emerge the other side, into the floor void of the front room. From there they go round the rest of the house which has floorboards and voids. Presumable a little drilling was needed for this solution, rather than trying to cut channels in the concrete.

Anyway, I have just noticed a green powder on one of the pipes, where it emerges/disappears into the concrete.

Can't see any pressure loss in the system, but this is clearly an early leak ?

All pipes were replaced 8 years ago (I saw it with my own eyes) so these are (to me) fairly new pipes.

How far from the stain is the leak likely to be ? Can it be *below* the stain, and capillary action has caused the liquid to draw up ? Or is the leak likely to be exactly where the stain is ?

Best solution to cut the pipe out, and replace ?

Copper pipes are meant to be sleeved if they go through anything with cement in it as the cement attacks the copper. Plumbers normally wrap pvc tape around the pipes, but they often don't.

Of all the copper pipes I have removed in these situations, the only visible damage to the pipes are where they emerge from the concrete - that is to say, the pipes are normally unblemished where they have been completely encapsulated in cocrete, but where the concrete stops is where the verdigris and usually severe rot is.

If it were mine I would remove about 6-8 inches of the concrete along the pipe's length, cut out and replace about 6 inches in each direction (both above and below ground) and wrap this new piece in insulation tape before re-concreting.