The outhouse sits immediately to the south-west of a cottage at Fánta Glebe, on the site of Fánta Castle, and the working assumption is that the windowsill was salvaged from the castle itself when the structure fell into ruin or was dismantled. It is the kind of quiet recycling that happened constantly across rural Ireland, where cut or shaped stone from earlier buildings was too useful to waste and too heavy to move far.

This practice of incorporating older architectural material into later, humbler structures is sometimes called spolia, though in an Irish rural context it was rarely a deliberate statement of prestige or continuity. It was simply practical. A dressed stone windowsill represented skilled labour and good material, and a farmer building an outhouse had every reason to use what was already on the land. The result, here at Fánta Glebe, is that a fragment which may date to the castle's working life now forms part of a field wall enclosing a roofless shed, the two phases of construction separated by an unknown number of generations but occupying almost the same square of ground.