Structure Five is the earliest building so far excavated on site.
Dating to around 3300BC, it was built some four centuries before the last construction in Trench P, Structure Ten.
An elliptical building, Structure Five is architecturally similar to the Knap of Howar, in Papa Westray — but in typical Ness fashion is much bigger, measuring over 16 metres long and 6.5 metres across.
If our dating is correct, Structure Five is now the largest Early Neolithic, non-funerary, building in Orkney.
Unlike the later buildings in Trench P, which are divided internally by large piers, in Structure Five upright slabs, partly built into the walls, defined the internal space to create an interior that looks strikingly similar to that of stalled chambered cairns, such as Unstan, to the south of the Ness and across the Stenness loch.
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 abandoned entirely and covered by midden and rubble, but the area continued to be used, as shown by evidence of later postholes, stone settings and features.
Initially, we thought that Structure Thirty-Two — represented solely by a curved wall in the south-western section of Structure Five — was a later addition to Structure Five (something akin to the curved wall inserted into Structure One at the start of its second phase) that related to the re-use of its south-western section.
It now seems, however, that it was separate building, built on the ruins of its predecessor. From the evidence so far it seems that when Structure Thirty-Two was built the walls of Five were still extant and sections perhaps incorporated into the new building.