Newly Skimmed and Painted Wall has Patch of Different Colour

[neilmuzz]

Hi,

Wondering if anybody can shed some light on a decorating issue. Had a room skimmed & painted recently by contractors. Was delighted with the work, apart from a large patch on one of the walls that was a different shade to the rest of the room. The plaster was dry according to the decorators that did the work, and it certainly looked dry. however after 2 weeks and attempts to dry out the wall using heat & air there is no improvement.

Photo attached, really hope there isn't damp or something, but if anyone can help it would be appreciated.

Cheers

[welsh brickie]

it is damp, at that height its unmistakable

[neilmuzz]

Ok, well thanks.

What kind of damp? Can it be rising damp if we have a cellar space below? Its an internal wall so cant be from external sources?

Anybody any idea how we get rid of it & how costly this is likely to be?

Ta.