Metal Roofs are one of the most common commercial roofs. They are easier to maintain and are somewhat affordable compared to other types.
A commercial metal roof is made up of several layers.
The bottom most part is called the structural cassette. This is the base of the whole system that provides shape and support.
The next layer is the vapor control layer which leads the moisture to the insulation layer.
After the vapor control layer, you can find the aluminum st clip tat holds the insulation.
The top most layer is the seam sheet.