Damp Spots

[gmalloch]

In my bedroom at home I am finding that there are damp black spots on one wall that started at floor level and are moving up the wall. The wall is damp to touch and the spots can be wiped off. Condensation does build up quite heavily on the window in the room overnight and the wall is quite shaded. I try to ventilate as much as possible and also use a small dehumidifier. The particular room in question is adjacent to the bathroom. The flat is around 40-50 years old on ground level and was built originally with a chimney and fireplace which is now closed off. Other than that the only permanent ventilation I am aware of is through the vents at the top of the double-glazed windows. Any advice much appreciated!

[joules99]

some things i can think of are having an extractor fan in your bathroom, a cooker hood and or an extractor fan in the kitchen and also there should be vent in all blocked fire places for, air circulation. but the problem could be rising damp, which i think you would need professional help with.

[pamaddy]

this is purely a ventilation problem and will not go awayb until you ventilat e .the black spots are spores which only grow in pure water[condensation]