I have a 1930's semi. The downstairs lounge window is showing damp stains on the wall above the window recess (recently re-plastered). The window (UPVC) was replaced 2/3 years ago and the outside seals look intact. The outside wall is rendered up to the roof but again I cannot see any breaches.
The window does face the direction of rain showers. I have not checked the guttering, is it possible rainwater is penetrating the outside wall from the roof, running-down the interior brick-work and exiting over the window-recess? The rendering has some 'blown' patches, should I check the roof (no felt-lining), guttering before attempting to strip the rendering?
