Flashing is a finishing trim that can be installed on a roof either for aesthetic or functional value. Generally it is manufactured from the same material as the roofing sheet or panel and its most important function is to keep roofs watertight. Flashing is commonly used to seal ridges, valleys, wall abutments, roof vents, slope changes, etc. but its uses are virtually limitless. Roof Systems’ flashing can be fabricated in virtually any imaginable straight edged shape, and is normally available in up to 20’ lengths.