Mold at sides of wall at the window

continualdiamond

Just washed the inside on my bedroom window and noticed the mold is starting to come back.

Last year i took away the wall paper that had been placed right up to the window edge as it was peeling away anyway. I sanded it all back and then painted it.

Now i can see spots of black starting to come out on the paint. What can i do to help it?

The radiator is under the window, should i open the window slightly every night to help with ventilation?

In all fairness i've hardly opened the window at all during winter, so im guessing thats the cause of the problem, no ventilation and having the heating on so much lately.

bobinbognor

Couple of clues...last years peeling paper was probably caused by damp. You removed the paper and painted the wall, presumably with emulsion paint. Now you have mould on the paint at the edge of the window.
Mould will grow wherever it is damp and cool. Warm air absorbs moisture, cool air displaces moisture, so the mouldy place by your window is probably at a cool spot. Treat the mould with a preparatory mould spray or use diluted bleach. The cold spot might be a breakdown of any cavity insulation if fitted or loose or missing mastic on the outside of the window. You may have replacement plastic windows and this one was fitted badly without insulation on the inside of the cavity. Check outside to see if you can replace any missing mastic. Leaving a window open a little will help because any moisture on the wall will be absorbed by warm air passing over it. Hope this helps. Bob