Brazilian Alpina 500mm x 450mm 1st Quality Natural Slate - Graphite Our slates are usually delivered on a Six Wheeled Lorry (11m Long & 2.4m Wide) with a Tail-Lift facility to off-load on solid level ground with a Pump Truck.   Non compliance to delivery restrictions may result in additional Delivery Charges. Should you specifically require Crane Off-Load or small vehicle please notify us at the time of ordering, as an additional charge may be incurred.   Please allow 5% extra in the ordered quantity to cover acceptable Breakage in transporting Natural Slate Products. Description Brazilian Alpina Grey/Green Natural Roofing Slate (30 Year Guarantee). Brazilian Slates are a natural sedimentary stone with excellent consistency which requires the minimum of grading and represents excellent value. Alpina is a natural Brazilian slate of the highest quality, selected from the finest deposits and produced at some of the best facilities in Papagaios, Brazil. It is available in two colours: grey/green and graphite, in a variety of sizes, and with its flat surface and pleasing shade variations can be relied upon to create an attractive and long lasting roof. Alpina slate has virtually no unstable minerals such as pyrites, graphite, carbon and un-oxidised irons and will withstand the most severe weather conditions. It is unaffected by sunlight, ultraviolet light and even acid rain. Laid correctly Alpina slate will last the lifetime of the building and is ideal for use on any major project including supermarkets, schools, city offices and prestige homes. Quality Alpina slate is a tough natural material and samples are regularly tested to the following national standards: British Standard. BS EN 12326-1: 2004 Product specification for roofing slate. Exhibited the top Class A1 for water absorption. Exhibited the top Class T1 for thermal cycle resistance. Exhibited the top Class S1 for sulphur dioxide exposure resistance. Good flexural strength both transversely and longitudinally. Acceptable non-carbonate carbon content. Slate Grain and Surface Characteristics. Most slates have a secondary plane of cleavage or grain which can only be determined microscopically. However this grain should not be confused with the texture which can be seen on the surface of the slate which is influenced by the direction in which the slate is split with a chisel, either from the top or the side. Alpina slate has a normal texture using the classifications detailed in BS EN 12326.