CONDENSATION MARKS ON CEILINGS / WALLS
Is it a leak or condensation?
How do I stop condensation marks?
A typical condensation mark, on the outside facing wall of a bedroom interior. (wall and ceiling)
Condensation marks can sometimes look very much like leaks, typically they occur on an outside facing wall or the edges of ceilings (especially when loft insulation is not rolled out to the very edges) also on window panes and aluminum window frames, it can also be found behind beds when moved away from walls and sometimes even in wardrobes.
These marks are caused by warm moist air in the bedroom, bathroom or around the house being drawn to a cold surface. Cooking, showering and even breathing creates plenty of warm moist air, this is then going to seek out the coldest surface to land on. The answer is ventilation, the more fresh air circulation the better.
Try to leave windows ajar or on locked night vent. Alternatively invest in a small dehumidifier if the condensation is really bad.
It’s very similar to sitting in a car on a cold day, the longer you sit there eventually the windows steam up, this is caused by warm moist air from breath. However if you turn on the fan heater, the condensation slowly disappears with the air flow.
If you were crazy enough to wallpaper the inside of your car windows, similar marks to the very top picture would appear after time. Eventually if left untreated a very fine black mould is formed.