Below is a 37' x 37' single sloped (flat) roof (contemporary style) Porte Cochere for a New Best Western Hotel renovation completed in March 2016. Below are some before and after photos showing a structural steel sub-frame and an aluminum screw base and cap skinning system that will hold the 25mm opal 5x wall polycarbonate roof glazing. On new renovations the existing columns (piers) can possibly be used....consult your local engineer. The porte-cochere is a stand alone structure with a lower canopy attaching to the building over the main entrance. Both porte cochere and canopy will have large gutters. Another flat roof porte cochere to review is in South Carolina for a Cambria Inn.
Steel sub-frame by others.