The earliest building excavated on site to date, Structure Five is currently the largest Early Neolithic, non-funerary, building in Orkney.
Until 2021, this early date was based on the architecture – an elliptical building very similar to the Early Neolithic Knap of Howar, in Papa Westray, but much bigger.
The discovery of round-bottomed pottery in the southern half of Structure Five confirmed its early date. This ceramics style generally preceded the appearance of Grooved Ware pottery in the later Neolithic, c3200BC.
Unlike the later buildings in Trench P, which are divided internally by large piers, upright slabs built partly into the inner walls defined Structure Five’s internal space.
Over its lifetime, Structure Five went through episodes of rebuilding and remodelling and continued to be used after the south-western section collapsed.
Eventually it was entirely abandoned, and its remains covered by midden and rubble.
The area continued to be used, as shown by Structure Thirty-Two as well as evidence of later postholes, stone settings and features.
Over the years, however, it has become clear that Structure Five’s history is much more complex than originally thought.
It had always been assumed that the building’s northern end was primary and that the southern end was perhaps a later, tacked-on, addition. A trench extension in 2021, however, revealed archaeology suggesting there is a lot more to the building’s biography.
The curve of the newly exposed western wall, for example, suggested the size of Structure Five had been underestimated.
Originally suspected to measure over 16 metres long, extrapolating from the wall curve it is now likely that Structure Five was much bigger than that – its southern end lying several metres beyond the trench edge.
The extension also showed that Structure Five’s southern end was the original build. At some point the building was extended northwards, towards what is now the Loch of Harray. This addition perhaps saw the primary entrance, on the western side, sealed off and two new doorways added in the south-eastern wall.
Structure Five, unlike the later buildings on site, was constructed on natural glacial till – the original ground surface 5,000 years ago. The difference in height of the glacial till outside and inside the building shows that the building’s interior was below ground level.
This probably accounts for the clay sealing found on the lower courses of the walls – a feature also encountered at the Early Neolithic settlement site at Smerquoy, at the base of Wideford Hill.
Without the clay barrier, Structure Five would have filled with water in wet weather! This may also go some way to explain the insertion of what appears to be a large drain at the northern, lower, end of the building.
Although excavation of the occupation layers inside Structure Five are in the early stages, the structure appears to have contained stone-built furniture akin to that encountered at other Neolithic settlement sites in Orkney.