roof pitch factor 4

https://wiki-site.win/index.php/What_Is_a_Roofing_Square_and_Why_Roofers_Rely_on_It

The roof pitch factor, also known as the slope factor, is a multiplier used to calculate the actual surface area of a sloped roof based on its pitch. For example, a roof with a 6/12 pitch has a factor of about 1.12, meaning the surface is 12% larger than the building's footprint, which affects material estimates and costs.