The answer to 'what causes flat roof' is that flat roofs are typically caused by the design and construction of the building. Flat roofs are created when the roof is built with a slight slope, rather than a steep pitch, to allow for water drainage. This type of roof design is common in commercial and some residential buildings, as it provides a practical and cost-effective solution for roof construction.
Flat roofs can be made from a variety of materials, including built-up roofing (BUR), modified bitumen, single-ply membranes, and even metal. The choice of roofing material can also contribute to the causes of flat roof issues, as some materials may be more prone to leaks, ponding, or other problems over time. Additionally, the quality of the installation and regular maintenance can also impact the performance and lifespan of a flat roof.