The vast majority of Commercial Buildings are covered with flat or low-slope roof systems. This is because most of the operations within these structures don’t benefit significantly from operations within the restricted space of an attic. When architects or contractors generally think of flat or low-slope roofs these days – they think of membranes such as EPDM, PVC or TPO.
However, metal roofs are growing in awareness and acceptance in low-slope roof situations (where pitch is less than 3:12). The fact is, Metal Roofs can be constructed with pitches as low as 1/2:12. This article from Building Design and Construction describes the benefits of metal as a commercial flat roofing material.