Ok so we have an attic bedroom that has a fixed staircase and no door or hatch, so open to the rest of the house. We have just had the whole roof replaced, yey no more leaks in bad weather! However we are now noticing patches of condensation on the walls, mainly appearing over night, query breathing? room is slept in!!! Patches seem to be where the air vents are for the roof I guess it's much colder there. Occasionally like today they have appeared during the day, whilst hubby was working from home up there.
We have purchased a 10ltr dehumidifier which we have on over night and leave the velux window open an inch or so on the catch.
What I want to know is if we need to keep the dehumidifier on 24/7 during colder months and is it pointless having the machine on if the window is also open? the room has a constant flow of air from the house. Any other tips to help with condensation spots would be helpful.