As produces only natural products from the finest raw material each slate has its own unique visual characteristics. Heather Blue and Heather Red slate often feature naturally occurring markings which are usually green. The quality of allows roofing slate to be produced to 48" (1.2m) or larger. Practical Welsh slate is exceptionally durable. It is unaffected by normal extremes of temperature and is highly resistant to acids, alkalis and other chemicals. It retains its colour, even in UV light and is impermeable to water. Welsh slate is non combustable and is compatible with all other building materials. Aesthetic Welsh slate combines beautifully with traditional and modern materials and provides the designer with a choice of colours and a natural, distinctive, texture. A Welsh slate roof adds character and quality to any building. Proven Longevity Welsh slate has hundreds of years of history and has proven to be the highest quality roofing material in the world. Welsh slate can provide numerous case studies and 100 year guarantees are available.