The 20/20 roof tile is a modern take on the traditional plain tile, using a modern interlock to provide greater flexibility and performance. Pressed from natural alluvial Humber clay, this premium material delivers improved longevity and natural beauty. The clay's irregularity adds charm and texture to any roof.The Sandtoft Wienerberger 20/20 tile is a new generation clay tile, designed to make a clay plain tile roof more affordable through a cutting edge design, which reduces labour, material costs and completion times. The innovative interlocking design allows this tile to be used on roof pitches as low as 15°.