Hi, hoping someone here can offer some advice. I'm building a flat roof extension with the help of a chippie to do the joists, firings etc. I'm just a bit concerned that the firings that he has fitted are too big. The joist span is about 3.4m and he has used 150mm joist ripped to nothing. I imagine that too much fall is better than not enough I'm just worried how its going to look down the side of the extension when I do the fascia etc, it looks a massive slope which I haven't seen on other flat roofs. Also there is a roof lantern, I was concerned about the water coming off the existing pitched roof onto the new flat roof behind the lantern and it just sitting there. Is this normal? Am I worrying about nothing and is this acceptable? Thanks.