While at uni I shared a house with nine other students, it was on the sea front and was always severely battered by the elements. I was fortunate to have a nice big room at the front with big bay windows but the chap in the room next door to me had a room like a box closet, small window and the heating was often on (them mostly being pansy southerners
)
We'd been there a year when I and another mate had noticed Dave had started witha funny cough...and that, thinking about it, he'd been coughing for a while (not a phlegm-y cough, just a dry one) and he actually
smelt mouldy! We went to investigate and half of his walls and nearly all his ceiling was damp and mouldy. No ventilation (he never opened his window, heating on) and general studently slovenliness had resulted in a horribly musty environment, seriously not healthy. He hadn't a clue, hadn't even noticed the smell or the mould. He tried to deal with it himself not wanting to bother the landlady thinking it was his fault...when we eventually got him to ring her she'd said it happened every year, she just painted over it
Hope you get it sorted Matt, the long term damage mould can inflict really isn't worth it.