How to build a gable roof over a shed or flat roof?
Probably the easiest way to put a gable roof over a flat roof is with prefabricated trusses. Odds are that you can clear span your flat roof and not worry about providing load support on any interior walls. A truss company will also provide the layout and engineering specs for your project and your local building department. They also will place the trusses on your roof. Depending on the size of your trusses, they are often very easy to stand up with just two workers. Once stood up and properly connected and braced, they are sheeted with plywood or OSB and then shingled with your choice of material, as per the engineering specs.
