Standard means all of the slates are the same size in both length and width. Random is where all of the lengths are the same size but the widths will vary. In this case all of the slate would have the same exposure, it is just the width of each slate piece that would be “random” or varying. In some cases, different patterns can also be achieved in the thickness of the slate and this is called graduated. This is where the thickness of the slate at the bottom is thicker and gradually the thickness decreases as it goes up the roof. This is more common in old European homes and newer affluent homes. This is the costliest application of all. The bottom line for the owner of the project is to determine what look they are going for at what price. But it can be easily said that all slate roofs are unique, beautiful, and last a lifetime.