Use this Slate Coverage chart to assist in calculating your required slate quantity.

The table below shows Slate coverage by number per m²
Size - Nominal (mm)50mm Lap65mm Lap75mm Lap80mm Lap85mm Lap90mm Lap95mm Lap100mm Lap105mm Lap110mm Lap115mm Lap120mm Lap125mm Lap130mm Lap135mm Lap140mm Lap145mm Lap150mm Lap155mm Lap
600 x 30011.912.312.512.612.712.913.
500 x 30014.615.115.415.615.81616.216.416.616.81717.317.517.718.018.218.518.719.0
500 x 25017.418.018.518.718.919.119.419.619.920.120.420.620.921.221.521.822.122.422.7
460 x 22516.417.017.517.718.018.218.518.719.019.319.619.920.220.520.821.221.521.9-
400 x 25022.423.424.124.524.925.325.726.126.627.027.528.028.529.0-----
400 x 20027.929.130.130.531.031.532.032.533.133.634.234.835.536.1-----
350 x 25026.127.528.529.029.630.230.931.432.732.733.4--------
350 x 20032.534.235.536.136.837.538.339.039.840.741.5--------
300 x 20039.041.543.444.345.446.547.648.8-----------

Values calculated using nominal sizes and incorporating a 5mm joint gap as per BS8000: part 6: 1990. We recommended the addition of at least 5% wastage allowance.

Slate Coverage & Cost

The actual cost of a roof per unit floor area of the building is determined by a number of factors, including roof pitch, slate size and head lap. By taking advantage of the various sizes and types of SlateScape roofing slate, considerable cost savings can be made.

Roof Pitch & Lap

The shallower the roof pitch, the smaller the area of the roof slopes. This area reduction, however, does not automatically lead to a cost reduction because lower pitches require larger slates and laps. The full cost advantage can be taken by adjusting the lap to the minimum required, for the pitch of the roof.

Slate Coverage Click the image to download this information as a PDF, or visit our Downloads section for a range of useful information.