A record of our ancient Brochs, Hill-forts and Sculptured Stones of Scotland

Purpose of the Broch



With the major broch concentrations in Caithness and on Orkney, some experts, using excavation evidence from Bronze Age hut circles, have suggested that this is where the broch architecture developed. Not by incoming invaders but by indigenous peoples whose pedigree stretched back to the earliest times...


Using the design mantra ‘Form Follows Function’ could well explain the development of the massive construction, unique architecture and typical ‘cooling tower’ shape. Neolithic Orkney demonstrates the ability to plan and construct complex domestic, funerary and ritual stone-built sites. Therefore suitable constructional techniques and logistical abilities had developed during the Neolithic period and their structures were still in the landscape by Iron Age times.
It is difficult to maintain that brochs were defensible military sites as no evidence exists for wall-top defences or windows. A smokey fire lit at the entrance would have quickly suffocated the occupants. There is little evidence, in the north, of destruction due to assault, only time, poor construction decisions and, most likely, recycling of the stone for more recent use as for the long-houses beside Dun Viden broch in Strath Naver, Sutherland. 7


Inspection and excavation suggest two basic forms of broch.
Firstly, the simpler single but thick-walled circle of stone, faced on both inside and out with well-constructed courses and rubble infill. These may well have consisted of only a ground floor as at Nybster broch in Caithness. This site which has complex exterior structures added to the sea-ward side, indeed hanging on a cliff edge with a thick bastion added to the landward side. Excavation of this feature, in 2011, hopes to establish its chronology with respect to the broch structure. This dig has already revealed a cist feature within the bastion.
Secondly, brochs with more complex interior plans such as spaces and passages within the walls. Access passages, stairs to upper levels, wall cells and ‘guard’ cells in the entrances in many combinations demonstrated this complexity.

This latter class strongly suggests the inclusion of one or more upper floors with the floor timbers being supported on a scarcement such as can be seen on Carn Liath just south of Brora in Sutherland. 8

 No evidence exists for roofing structures which were probably built of timber. Turf or thatch has been suggested as a covering. Hides might have been more suitable, being a lighter material which would have allowed partial removal in fair weather giving light into a dark place and improving the inner environment.


 So what ‘Functions’ did this ‘Form’ follow? Why the massive shape? Well it has been suggested that a more productive form of cereal crop was appearing and that this may have created storage problems. The method of storing seed in pits in the ground was not suitable for the larger surpluses and hence the first grain silos in the form of brochs. The taller structures would have upper or even mezzanine floors as suggested by post-holes. Access would have been via spaces and stairs in the walls.

It has been noted that evidence for domesticated cats is associated with this period – useful for dealing with likely rodent infestation. Also, the grain milling moved from the use of the saddle quern to the use of the more efficient rotary quern during the period of broch construction. 9a 9b

 The use of hollow walls probably developed from a number factors.
Firstly, the amount of stone to be brought to site and handled into position would be reduced. Secondly, the walls would be lighter in weight and have lesser tendency to collapse. Thirdly, as well as allowing for access to upper levels, there would have been an air-conditioning effect which would have made the inside conditions more suitable for storage and the temperatures more comfortable for the inhabitants.

The inner wall construction may also have given a platform during the outer wall construction.
Given that wolves were in the wild in Scotland until the 18th Century and that the Iron Age was a time of strife, then to have the security of living in what must have felt and looked like a strong place to retreat into from the fears of the night and bolt the door would have reinforced the use of the design.

The broch would have stood as an impressive place in the landscape and, even when not needed for the above mentioned reasons, the broch would have then served as a way of imposing a message of prestige to neighbours and travellers. This is suggested by the fact that many of the sites stand watch over travel routes by land and water, some having no nearby agricultural resources and are most dominating their landscape.

It almost appears that broch-building became the fashionable thing to do, within a cultural boundary of some kind, irrespective of need or wealth.

The builders were possibly groups of itinerant stone-workers who could offer a range of design options to suit the locality and affluence of the 'customer'. The purpose of this study is to examine the evidence for territorial similarities and differences such as footprint, door orientation and constructional techniques so as to look for cultural or contructional similarities.

 As more sites are visited and their records are then added to the data-base, then some refinment or discarding of ideas will take place.