That older structure is a cashel, a type of circular or oval drystone ringfort once used as a defended farmstead, and by the time these houses were raised within it, its fabric had already been reduced to little more than a low ring of rough crag slabs. The houses are the later intrusion, yet they are not exactly young either, appearing on Ordnance Survey maps from both 1840 and 1916 without any indication of when they were first built.

The antiquarian Thomas Johnson Westropp, writing in 1913, described the cashel's wall as "nearly levelled when some houses were built in it," a phrase that captures something of the pragmatic relationship rural communities in the west of Ireland often had with ancient stonework. Rather than sources of wonder, such enclosures were quarries of ready-dressed material, and the building of new structures within or upon them was entirely commonplace. At Caherfadda, one of the two houses survives as a rectangular outline measuring roughly 6.3 metres east to west and 2.2 metres north to south internally, its double-faced drystone walls still standing to around half a metre in height, with a width of about one metre. A second house lies some 7.5 metres to the east. Both sit on a D-shaped raised platform, approximately 20 metres long and 10 metres wide, whose edges are marked by a shallow peripheral dip in the ground, suggesting the platform itself may preserve the footprint of an earlier feature beneath the later occupation.