Generally, roofing types and roofing products are typically divided up into two primary categories, steep slope roofing and low slope roofing.
The terms low slope and steep slope describe roof slope. The slope of a roof is often referred to as the pitch. The slope, or pitch, of the roof is determined by the vertical rise in inches for every horizontal twelve inch (12") length (called the "run").
Steep slope roofing is sometimes referred to as “residential roofing” because most single-family homes in the U.S. are constructed with some sort of pitch or slope to the roof.
Low slope roofing is often synonymous with “commercial roofing”. This is because commercial buildings typically have “flat” roof design, but many apartment buildings and townhouses have low slope roofs.