The conservation of dry stone monuments presents a unique challenge: often, structures such as brochs and chambered cairns are complex in architectural and engineering terms, meaning that a thorough understanding of the principles of their construction is necessary before they can be stabilised. The patterns of their collapse and decay can be equally complex, and often leave fragile remains of corbelled cells, stair chambers and lintelled passages that can be a hazard to both archaeology and the visiting public.

Equally important is the need to design an approach to conservation that preserves the important characteristics of the monument in such a way that visitors can understand the original form of the structure. Past approaches to drystone monument conservation have too often sacrificed the visibility and authenticity of original features for the purposes of simplicity.

Brochs, Iron Age drystone towers, are unique to Scotland and, as a group, constitute one of the UK’s most spectacular and distinctive archaeological assets. Yet they often present considerable conservation challenges.

At Clachtoll, Dunbeath and Dun Vulan brochs, AOC’s archaeologists worked closely with engineers, stone masons, Historic Environment Scotland and local stakeholders to stabilise and conserve the structural features of these monuments in a way that was sensitive to all of these concerns. Each site faced different challenges: coastal erosion at Dun Vulan and visitor footfall at Clachtoll, destabilisation caused by antiquarian excavations and later vegetation growth at Dunbeath. In each case, detailed 3D recording and analysis of the structure was used as the basis for project design as well as for decision making during the site works. By interrogating and interpreting the design of each broch, appropriate solutions for the stabilisation of the walls could be made, while at the same time gathering new information to be used in the future management and presentation of each site.