A machicolation is a projecting parapet or gallery built out from a wall, with openings in the floor through which defenders could drop stones or pour boiling liquids on attackers below. Finding the corbels for one on what is described in 1641 as a "fair slate house" rather than a fortified tower is a reminder that the boundary between domestic architecture and defensive architecture in early seventeenth-century Ireland was not always a firm one.

The house at Mullinderry is recorded as belonging to Edmond Hore in 1641, when he held it along with 120 acres. The building was probably already several decades old by then, constructed in the early part of the seventeenth century. Its proportions are substantial: roughly 22.5 metres north to south and 7.5 metres east to west, with walls approaching a metre thick. Narrow window openings, or lights, survive in those walls, and a large chimney flue projects outward from the south gable, a feature common to houses of the period where the fireplace was worked into the gable end rather than the interior. A stair return on the west side adds further complexity to the plan. Following the upheavals of the mid-century, the property passed to Captain John Trench, to whom Mullinderry was granted in 1688, one of countless transfers of land that reshaped ownership across Wexford and beyond during the Cromwellian and Williamite settlements. The house appears in the Down Survey parish maps of 1656 to 1658, the ambitious cartographic project commissioned to document Irish landholding in the aftermath of the Cromwellian conquest.

The building is still occupied today, though considerably altered over the centuries, and sits roughly forty metres east of the Owenduff stream. The survival of the machicolation corbels at the north-west angle is the detail worth seeking out, a fragment of fortified thinking preserved on an otherwise domestic facade.