Standing seam as flat roofing
In the picture above, we have a cross-section of a typical 180 standing seam, a 90 standing seam, and an uncoupled panel. At leska, we only use the 180 seams on roofs; they're stronger and more watertight.
As you can see from the cross-section, each panel, on flat surface looks like a cross section of a bucket would; even if water builds up a little bit the roof wont leak! This makes standing seam metal a perfect flat roofing material. It can be used on incredibly low-slope roofs!