What defines a steep roof?

A steep roof is defined as one that has a slope greater than 4:12. This measurement indicates the rise of the roof in relation to its horizontal span. Specifically, for every 12 horizontal units, the roof ascends more than 4 vertical units. Roofs with a slope greater than this not only enhance water runoff, helping to prevent leaks and water damage but also contribute to a distinctive architectural style often associated with steeply pitched roofs. Such roofs can also provide more usable interior space, often allowing for the creation of attics or additional rooms, thereby increasing a building's functionality and aesthetic appeal.

In contrast, roofs with less than a 4:12 slope are generally classified as low-slope or flat roofs, which have different considerations regarding drainage and insulation. A completely vertical roof or a roof with no slope does not align with traditional roof classifications and does not function effectively in standard roofing contexts.