Hi, I have a large shed (about the size of a garage) with a leaky flat roof. I have a couple of options, i could either re-felt it or use some metal corrugated roofing that will be removed from another garden building which will be taken down soon. I was wondering what the minimum pitch would be to make use of corrugated roofing? There is a slight pitch to the roof which I will measure (when the rain stops eventually) I like the idea of re-using the metal roof as it is in good condition, saves cash and saves me taking it to the dump. Is this a realistic idea? Or would it just be easier to re-felt it with good quality roofing felt. Thanks