Currently re-decorating a small bedroom. Took the radiator under the window off, and noticed a load of plaster behind had blown. The base plaster is 1930's lime plaster so it came off like butter, despite having been skimmed over with gypsum at some point. Bashed it all off and noticed that a lot of the mortar in the brickwork was extremely sandy/powdery and looked slightly darker in colour to surrounding areas and other places in the house. The mortar started falling out just by rubbing a finger across it.
See image below. You can see where I've scraped the really sandy plaster out from between the brickwork. This is a cavity wall so I'd be surprised if the inner skin was getting wet, although I guess if below the window then water could be ingressing somewhere there? All of the plaster above the exposed area sounds fine if I tap it, don't think that has blown, and the mortar seems ok there. None of the brickwork there feels "damp". Could this be historical water ingress, or do you think I have an active problem and need to get someone in to take a look?
Thanks in advance.
See image below. You can see where I've scraped the really sandy plaster out from between the brickwork. This is a cavity wall so I'd be surprised if the inner skin was getting wet, although I guess if below the window then water could be ingressing somewhere there? All of the plaster above the exposed area sounds fine if I tap it, don't think that has blown, and the mortar seems ok there. None of the brickwork there feels "damp". Could this be historical water ingress, or do you think I have an active problem and need to get someone in to take a look?
Thanks in advance.
