7.3.5.1 Roundhouses and Simple Atlantic Roundhouses

Roundhouses were constructed in a number of materials, and in the main, this probably relates to local availability. Many were solely built from stone and the more substantial of these stone roundhouses are identified as sARs or cARs (see below); others were built of stone and turf, turf only, turf and wattle or timber-only constructions. As a result, the term ’roundhouse’ includes examples of buildings in a range of materials. Simple stone-walled roundhouses, typically with wall widths that are thinner than sARs or cARs build on the roundhouse tradition of the Bronze Age, though no simple development sequence can be put forward. However, at Lairg the Iron Age constructions show some differences from earlier buildings. House 7, which had Iron Age dates, marked a departure from Bronze Age houses on the site because it used more stone and also had evidence of an internal post-ring (McCullagh and Tipping 1998; see Table 7.6 for dates).

Within this broad category, sARS are defined as having either one wall without intramural space or no indication of double wall in the upper stories. The wall construction of sARs is of a composite structure consisting of two faces and an uncompacted rubble-mix core; the walls were not built with layered courses throughout (Romankiewicz 2009). Many buildings published as duns but which do not have intramural spaces, would be considered sARs; see Fairhurst (1939); Harding (1984); Henderson and Gilmour (2012); Romankiewicz (2009, 381) for discussions of dun buildings.

Often all that remains of these structures for analysis is the lowest footing level, which often survives because it was built from stone, as a wall or as a continuous platform, especially when on sloping ground such as at Dun Ardtreck, Skye. Without upstanding structures, buildings can only be identified through the negative features that remain, such as a ring-ditch, ring-groove or post-ring. These distinctions, as Romankiewicz pointed out, mix functional and structural aspects. For example, the ring-ditch was usually created by repeated wear, while the ring-groove is a foundation trench and therefore a structural feature; both can appear with post-rings. The internal post-ring may or may not be discerned on the surface due to the use of post-pads (Romankiewicz 2009, Romankiewicz 2011, 20, 23ff).

Some timber roundhouses from the Highlands were exceptionally large. Two of the largest roundhouses known from the Highlands are from Culduthel. With a diameter of 18m and 17m internally, these structures were at the upper end of what was feasible to roof (Hatherley and Murray 2021). Investigation at Culduthel (MHG49950) revealed 22 timber roundhouses, most of which were completely excavated (see Case Study Culduthel Iron Age Craftworking Site). All of the roundhouses had postrings, and three had a ring-groove; the two large roundhouses that had the later date from the first centuries AD also had carefully cut ring-ditches. Most of the houses were workshops; indeed none of the structures can categorically be interpreted as solely domestic. The construction of large ring-groove buildings appears elsewhere in the Highlands, for example at Seafield West (MHG3058; Cressey and Anderson 2011), and elsewhere in Scotland, and may be a preferred way to construct large timber buildings in the early years AD (Hatherley and Murray 2021).

While the current evidence has fewer examples of structures dating to the early years AD, there are some examples, to which can be added the cellular buildings surrounding Nybster broch. Roman objects found at some cARs also provide evidence of occupation at this later period.