Many people will tell us flat rooves perform no worse under a given load or precipitation condition than pitched rooves, they both just have to be designed righ

Many people will tell us flat rooves perform no worse under a given load or precipitation condition than pitched rooves, they both just have to be designed right for it. But if flat ones are harder to design right, then they're more likely not to be designed right, so we end up with a larger number of edge cases where they're going to perform worse.