damp patch

[johnad]

please help
i have a internal wall and in just one spot a very small area has developed a damp looking patch it is around 4ft from the floor and is around 12" big
i cant belive this is damp as it is an internal wall and it is also directly above a radiator it backs onto a shower room but this has plastic cladding fixed over the exsisting tiles so i don't think this i the cause,
could it be something in the wall or paint as it had been painted several times before i moved in and papered it,
this is the second time this has happened the last time i glossed painted the wall before i hung the paper but still it has come back,
you thoughts please,

 

[jbonding]

where do the pipes travel to, that feed the shower?

 

[Softus]

I suggest that you avoid using the shower for a week, and see if the patch reduces in size or wetness.

 

[johnad]

the pipes are under the floor an nowhere near the wall
the patch is not damp to the touch just dark under the paper
if it was the shower surly it would be more at the bottom of the wall
i can replace the strip of paper but what should i put on the wall first
many thanks

 

[JohnD]

i can replace the strip of paper but what should i put on the wall first
many thanks

you should find and mend the leak, not fix the paper.

 

[Softus]

Either it's a water leak, in which case you should take note of JohnD's advice, or it isn't, in which case you should strip the decoration back to where the problem is and remove it.

Doing the latter first will allow you to discover which is the actual cause.