Having fitted sarking boards and roofing membrane, the next task for the joiners was to batten out the roof ready for tiling, and forming timber 'skews'.     'Skews' are a verge treatment seen widely throughout Orkney, be they lead covered, stone or formed from concrete.     Nothing especially complicated in their construction, as can be seen in the 'technical diagram' used by the joiners:     With no external block leaf, our options were a bit