Since the last slate quarry in Scotland closed in 1955, architects and builders carrying out maintenance and restoration and new developments in conservation areas have struggled to meet specifications for traditional roofs. It is also a problem for homeowners making repairs

The situation became so desperate that Historic Scotland and the Scottish government have studied the viability of reopening disused quarries. However, the current economic situation and the possibility of local and environmental objections make that doubtful.

Historic Scotland research confirms the reputation of Scottish slate as a long-lasting material, with a service life of 150 years or more, if fixings and support are regularly repaired. But this has generated extra demand, which currently can only be met by recycled slate from old roofs.

Low-cost slates are being imported from abroad – one company trading as “Scottish Slate” imports from China - but conservationists say these do not match the appearance of Scottish slate and there are questions about the durability of some.

Tom Brown