DuoPlain combines the classic proportions and good looks of traditional plain tiles with all the time and cost-saving benefits of a modern, large-format interlocking tile. Engineered for strength, ease of handling and ease of installation, it fulfils the three main demands of a modern roofing site. Now available in seven popular colours with the addition of our brand new Blue, DuoPlain also comes with a full range of matching fittings and accessories. Properties Tile finish: smooth finish. Tile profile: interlocking concrete plain tile. Certification BBA certified. DuoPlain Tiles conform to BS EN 490: 2004 Concrete roofing tiles and fittings for roof covering and wall cladding - Product Specifications.