PigletJohn: why is there a wet strip along the wall? Pic included

[sh77]

Hi
Would be so grateful for any insights.
Just renovating a house. Frehly plastered and painted. There has been very heavy rain in my area. I am wondering why there is a damp strip along the wall. Seems to be above DPC line. Could water be coming through cavity? Behind this wall are kitchen appliances which haven't been switched used.
Any advice?

Did the plaster dry out completely before painting?

Yes I'm pretty sure as there was a couple of months between plastering and painting.

did you do a piss coat before putting paint on the wall.
I believe it's 50%/ 50% water and paint. Then, when dry you put your main paint on top.

Haha funniest auto correct above....did you mean mist coat?? 😂😂

No, ashamedly not, it's what we call it because it's piss strength.
I know, I'm terrible. Just got used to hearing it as have done up several houses and had various tradesmen on site at times.

the wall does look curiously wet and I think I can see the shape of bricks showing through. I wonder if there has been a water leak. Is the kitchen worktop of a height where dripping water could have gone into the wall on the other side? Is there damp on the other side?

Tape a piece of clear plastic tightly to the wall and see if water droplets form on the wall side or the room side.

Is it level with where the electric sockets were fitted on the other side, resulting in cutting out and chasing?

The DPC is normally nine inches above where ground level used to be when the house was built. If you mean that damp was covered up by plastering over a wet wall, perhaps with useless chemical injection, and the water has now travelled up above whatever was hiding it, then you need to find and remedy the source of the water. For example if there is a solid kitchen floor, there may be a leaking pipe in it.