Ants or Rising damp in cavity

[gally35]

This is appearing on the outside of a wall below the DPC. It looks like water oosing from the inside.
It is adjacent to a embeded wall sink in a toilet and shower tray in a bathroom the drain cover is seen on the left. There is no sign of damp inside the house which has a concrete tiled floor and walls. There is a very large ants nest running along the wall in the cracks in the concrete and slabs. But ants do not make water. Is this rising damp and how do I fix it? Thanks

 

[George_engineer]

It'll be a leak somewhere. Or, a fault in the gutter dripping onto the wall which just happens to coincide with the bathroom.

Rising damp isn't really a thing and would not occur in such an isolated manner. Also, rising damp, by definition, doesn't occur below the DPC as brickwork below the DPC is 'allowed' to be damp.

 

[^woody^]

It looks like it is below the DPC, so not rising damp. May be rising ant though.

 

[JohnD]

You have a water leak. Probably close to the highest point of the damp patch. Repair it.