From your chosen size of slate and headlap, calculated using our headlap tables, use this coverage table to calculate how many slates per m2 your roof will require.

The most popular slate size in Southern England is 500 x 250mm, and 400 x 250mm in the North of England and Scotland.

Please Note: Values are calculated using nominal sizes and incorporating a 5mm joint gap as per BS 8000: Part 6. We recommend the addition of at least 5% wastage allowance. These figures are for guidance only and dependent on the joint gap allowed. This table gives a range of sizes for your information. Other sizes may be available, please contact us for further information.

Given the multitude of different sizes and headlaps available, and the peculiarities of the production process, the installed cost of any slate can be influenced by the size selected, the quantity of batten and fixings required for that particular slate size.

Once you have calculated how many slates per m2, decide on which fixing method to use by referring to our article on Hook or Nail fixing.