Advance excavation at Ballyknock uncovered the remains of a circular structure roughly ten metres in diameter, its form preserved not in standing walls but in patterns of post-holes cut into the ground. An inner circle of these holes defined the likely line of structural uprights, with a partial outer circle extending to the north and northwest, hinting at the original footprint of what may have been a roundhouse, the typical domestic form of prehistoric Ireland, in which timber posts supported a conical thatched roof.

Pottery found in association with the structure points tentatively to a Bronze Age date, placing it somewhere in the broad span between roughly 2500 and 500 BC, though the attribution remains cautious. Two pits lay close by, one immediately to the south showing clear evidence of burning, suggesting use as an oven or kiln of some kind. Radiating outward from the structure, further lines and arcs of post- and stake-holes may represent paddocks or windbreaks, the kind of functional enclosures that would have sat around a working farmstead. The absence of occupation layers inside the structure, which might otherwise confirm its domestic use, is explained by local knowledge of the area: extensive field alteration and vegetation clearance had taken place there over the years, and this disturbance most likely removed or obscured the evidence that would have settled the question. What survives is a ghostly outline, legible mainly because machinery and careful archaeological attention arrived before the bypass did.