Corner Flashing is used both inside and externally behind the cladding. We use top-notch mild steel and aluminum to make this flashing. It is intended to be mounted at the wall panel corners. Additionally, it is intended for the rough opening corners beneath windows. This flashing is important to prevent leaks. Self-adhering flashing can be combined with flashing to make a pan flashing for windows, and corner flashing should be sealed to a rough opening.