Hi. I have a flat concrete canopy over the front door of the house. (approx 2Mtr wide and 1Mtr deep). I want to build a pitched roof with sloping sides. I'm quite good at DIY, so am really looking forward to this. My problem is I have no idea of what angles/pitch to use or the distance to have between the batons ready for the tiles. I want this to be my own design but need some basic info to start with. Advice please.