Kitchen splashback against interior of external wall causing condensation in plaster

Hi, The problem is humidity is getting behind the splashback which has made salts to build up,you will need to remove the splashback and the paint and apply a salt neutraliser to the plaster.When you re-fit the splashback you will need to apply a bead of silicone to make an air tight seal. Mike

Hi, Is it a solid external wall? Has the wall been rendered or plaster boarded? I'd also check the brickwork outside for any defective pointing/cracks within the brickwork around the same area of your splash backs. If you have high humidity in the room, which is likely from cooking etc, the moist air could well be getting trapped between wall and splashback, but it's worth checking to see if there is another source to ensure that the moisture is not coming up or through the wall to prevent further issues. Any questions, I'm here to help. Best of luck Gary