I have started some work with a contractor to replace a roof on a terrace. They have removed the existing roof, and have left apparent some metallic bars placed on top of pillars. It feels sturdy in the sense that a 70 kg man can pull himself by the arms grabbing the metal bar, and it does not break (it bends ever so slightly).
For various reasons, I have started to lose confidence in the contractor. I worry about his competence. I am not sure I should cut the project now (which would be painful financially and would create conflict).
So I feel I need to educate myself on how to make a tile roof, to make sure I can watch what he does.
Three questions in total, but I am grateful for any advice, any partial answer:
How can I make sure that the metallic bars will indeed support the weight of the tiles, plus the weight of the drywall he will put below?
What minimum slope do the metal bars need to have?
What other advice do you have for me, to watch out for in that situation?
Photo of the tiles he bought is below.