Yeh im not one for feeling the cold until its freezing so a lot of the time i had to have the windows open whilst it was on! I never thought about roof storage actually, theres a big 180W panel up there and 2 skylights so not much space left really.
Yep flagstone was a friends suggestion, got it from a builders skip one day on my way home so it was free. Ergh drilling stone is a nightmare! im used to metal and wood but yes it was really long drilling through the flagstone. and another thing not mentioned here was the panic when i thought id drilled into my fuel tank like an idiot. thankfully i was just being paranoid