Alternatively you could use a 12 inch high starter slate thereby guaranteeing a 3 5 inch headlap on the starter course and an 8 5 inch exposure on all field slates.
How to set out a slate roof.
This can be carried out cheaply and it s work you can comfortably undertake yourself.
Although a slate roof is initially quite costly it will often last for a lifetime and beyond.
Run a string up the edges of the roof to give yourself a straight edge to follow when laying the slate tie the string to temporary nails or chalk lines up the roof edge to align the inside edge of the slate in order to leave a one inch overhang on the outside.
In order to maintain your investment and make sure it lasts a slate roof will need regular maintenance.