bad condensation and black mould

trixyben wrote: »

i have a problem which is now coming back due to having the heating on more often, its in one room a bedroom and the condensation gets very bad at times, there would literally be water running down the walls and window, and black patches on the ceiling, last couple years just used a dehumidifier but need a more permanant solution...

i understand the heat is meeting a cold surface and therefore turning into condensation, but what can i do, i put extra insulation in attic above room, used a special paint for this problem with no joy, put extra vents in the window still no good, was considering installing a vent in the wall or could anyone advise on the best option?

It's moist air (high relative humidity) in contact with a cold object that causes condensation, not heat:). If your air is "dry" little condensation should occur.

You need to tackle this problem on a number of fronts.

First reduce, as much as possible, moisture entering the house by f.i. not drying clothes indoors, if gas appliances are used for heating or cooking then ensure there are adequate extractors/vents installed and working.

Where moisture generation occurs f.i. bathrooms make sure the extractor fan is adequately sized, working properly and is used. When using an extractor in a bathroom, close the door and also open a window.

Ensure each room is properly vented f.i. by installing wall vents. There are good energy efficient vent systems available nowadays.

Ensure all room are adequately heated. Very often, condensation and mould occurs in bedrooms which are cooler than the living areas because of the temperature effect on relative humidity.

Investigate improving the insulation or that the current insulation is installed properly. Be very careful if insulating the walls with internal insulation as this in many cases can make the situation worse.