Clachtoll broch, located on the north west coast of Assynt, is one of northern Scotland’s most iconic archaeological monuments. Surviving in places to first floor level- over 3m above the bedrock- the remains of this spectacular drystone tower are thought to be around 2000 years old. Very little archaeological investigation has been carried out at the site.
Historic Assynt has worked to protect, study and make the broch accessible since 2007. Despite its massive and enduring appearance, the broch is very actively decaying, mainly through coastal erosion, which has claimed around a quarter of the wall already and continues to destabilise the structure.
A conservation management plan for the broch was written in 2009 in consultation with Historic Scotland, archaeologists, engineers and architects in order to provide an assessment of the cultural significance of the broch and to help in planning a strategy for conserving the monument. The conservation appraisal highlighted several areas of concern, the most urgent among them being the area around the entrance, the broken wall ends exposed to the sea and a void of unsupported masonry on the south side of the site.
With support from Historic Scotland and a grant from the Heritage Lottery Fund, structural consolidation of the entrance was carried out in 2012 as part of a public archaeology project known as Life and Death in Assynt’s Past. This work stabilised unsupported lintels and unsafe areas of the broch wall, and afforded an opportunity for archaeologists to inspect the complex engineering involved in the building. Analysis of the structure gave the archaeologists confidence that Clachtoll broch had once been of tower-like proportions, similar to some of the best preserved examples such as Dun Carloway, Dun Telve or Caisteal Grugaig. Charcoal was found on the scarcement ledge within the broch interior, sealed by rubble collapse, which provided a date in the first century BC or AD. It is likely that the interior of the broch has remained untouched since.
The second phase of conservation works, carried out in early 2014 with support from Historic Scotland, comprised the installation of a temporary supporting brace to the unsupported masonry on the south side of the monument. These braces, designed to prevent a collapse of the southern portion of the wall, will eventually be removed when a more sensitive solution can be installed.