Early Architecture Project: Experimental building in dry stone at Spittal, Caithness

In a disused part of the A&D Sutherland quarry at Spittal, Caithness, work has been underway over the past few years building and demolishing chambered cairns and brochs. The overall aim of the project is that of understanding the architecture and engineering of early structures so that we can distinguish between them. John Ruskin argues that architecture is everything about a structure that was not strictly necessary for its structural integrity. Identifying those elements of the structures that were subject only to the free choice of the builders allows us to approach the minds of their builders more closely. Understanding their engineering and the mechanisms of their structural decay and failure improves our ability to understand the taphonomy of the monuments we find in the field.

Directed by John Barber of AOC Archaeology Group and Paul Humphries of the Caithness Archaeological Trust, the work has been undertaken as part of the River of Stone by a combination of local community members, professionals and academics/students. In June and July of 2006, work was undertaken on three monuments. The first was the demolition of a long cairn built a year earlier. This was first recorded by laser scanning which allows us to quantify its volumes and weights. The process of collapse of one side of the chamber was progressed stall by stall and the fallen material was then scanned and excavated in a series of strips. This revealed that only about one third of the chamber floor was impacted upon directly by fallen stone. To explore further the location and extent of the destructive footprint of the collapse, animal bone and a sandwich of polyurethane foam were placed on the cleared chamber floor in two separate compartments. Collapse on the chamber side wall/roof onto the floor-targets resulted in patterns of impact and of destruction that are now being studied.

Construction of a second cairn, a circular chamber, to be approached by a passage, was progressed in 2006. Our specific interest here was the testing of three different engineering solutions to the issue of mating the passage and chamber which we can observe in ancient chambered cairns. We also wished to test the theoretical indestructibility of a completed, circular, corbelled chamber.

The third project concerned the completion of the construction of a segment of a broch followed by its demolition. The segment amounted to one eighth of the circuit of the broch which was built to half scale and modelled on the wall structure proportions of Gurness. Chains were built into the broch segment to allow for its progressive demolition. Laser scanning facilitated its quantification and was used to record the collapse, when the latter was excavated away in strips. We believe that we are getting closer to an understanding of the structural engineering of brochs and are certain that we now have a more forensic understanding of the nature of the remains found in the field.

Work will continue with the construction of a long cairn with enclosing chamber, the completion and partial demolition of the circular chamber, the laying out and building start on a full model of a broch at half scale and off-site, and the start of work on a full scale broch.

We are grateful to A&D Sutherland for the use of their quarry and of their stone and for all their support and assistance over the past three years. CASE has supported this project from its onset and Caithness Archaeological Trust has been indispensable to its growing success. Above all we are grateful to all the (now over 200) members of the local community who have visited and worked on the site from time to time and especially to George and Nan Bethune and Paul Humphries (members of CAT), without whom the project simply could not happen.

AOC Archaeology Group Managing Director: John Barber
Research Partner: Caithness Archaeological Trust