What are meant by the terms weathering, semi-weathering, fading, and unfading?
Unfading slate is slate which changes very little from its freshly quarried look and whatever changes do occur are relatively uniform throughout the roof. If slate isn’t unfading it is known as “fading” (also “weathering” or “semi-weathering.”) The amount and type of fading or weathering varies from color to color and quarry to quarry. A reputable supplier can usually offer a fair prediction of the weathering characteristics of their slate. Fading and color shifts do not affect the longevity of top-quality slate, but will affect the appearance and thus should be anticipated. Fading and weathering involves all or part of a slate turning some degree and shade of brown.
