Profile: Matthew Charlton Slate Merchants manufactures and supplies roofing and flooring slate products. Our products include blue black roof slate, grey black roof slate, flooring slate, ridge tiles, roofing tools and welsh slate. Hadrian slate is blue black in colour and very similar to other blue black slates such as penryn slate and bangor slate. They are 4 to 7mm thick and available in sizes ranging from 300x200mm to 600x300mm, with slate and a halves available for most sizes.