You can see the bottom row of slates being positioned. On the turrets at Balintore Castle, the first row of slates is square cut, subsequent rows are cut on the round - the so-called fish-scale slates that are very much the look of Scottish Baronial architecture.
Notice there is a little "kick" outwards in the shape at the bottom of the turret. This is called a bell curve, because it echos the shape of bell. This is labour intensive to achieve, but it is precisely the small details like this which give a building its class.
|bottom square-cut row of slates on turret|
It is fascinating that slating is one of the few remaining professions where hand tools still hold sway, and methods have stayed the same since time immemorial. In other fields such as carpentry, power tools have taken over. The photo below shows the three basic tools of slating. There are two edging tools: the slater's knife and a "sage" to strike against, which put an edge on the slate; and a hammer to nail the slates in place.
|the tools of slating|
Below you can see how the knife and the sage are used to put a curve on the bottom of the slate. The speed Andy can put a curve on a slate is phenomenal: a few sharp chops at the right angles and of the right force are all that are required. If the slate is hit too hard or too softly, it could shatter! You chop the slate at the back surface to give a sharp edge here and a bezel on the front. If the bezel was at the back, it would draw the water underneath by capillary action, and cause the wood in the roof to rot.
|how to cut a slate on the curve|
It is important to sort the slates by size before laying. The roof at Balintore consists of "layered courses" i.e. the higher you go up the smaller the slate gets. This looks classy but is very labour intensive. I was intrigued by Andy's yellow rule - it didn't seem to be marked in either centimetres or inches. I have since found out it is marked in 3/4 inches, which is how you size slates! Historically there are regional variations: the slaters of Dundee used whole inches: the slaters of Fife used 1/2 inches. So Andy was apprenticed to use a sizing system, which would be reasonably compatible with either.
|the mystery markings on a slater's rule|
If you have made it this far, you are much the better informed about slating. :-)