R68 Blue-Grey-Green Roof Slate / Special offer roof tiles / By stoneandslate Size (mm) Price (£) (excluding VAT and delivery) per sq.metre (m2) coverage per tile 350 x 200 16.38 0.45 400 x 200 16.94 0.55 400 x 250 17.96 0.73 500 x 250 18.50 0.98 Non fading, pre-holed. Similar to Burlington blue slate.