Firstly, I'm quite clueless about DIY/home matters - I've had marks on part of the main room ceiling in my top floor flat (with a loft above) for a month or so, but they've particularly worsened over the last week. There's no water coming in through the ceiling but the brown marks are a bit colder to the touch than the non-brown areas - the marks cover an area about 1/2 a metre wide. I presume I need to get a roofer out?

