Flat and low-slope roofs do not shed water the same way a steeper roof does, so drainage, seam integrity, and material layering become much more important. On the Cambridge page, Aucoin specifically highlights flat and low-slope systems as engineered roofing assemblies built for drainage and thermal movement control, which is a big part of why installation details matter so much. At Aucoin Roofing, flat roofing is treated as a complete system, not just a surface covering.