It is, according to researcher Georgina Scally, a Dutch Billy, a house type that was once common across Dublin but has been reduced over the centuries to a small handful of survivors, easy to walk past without recognising what you are looking at.

Dutch Billies are the vernacular name given to a style of terraced house characterised by a stepped or curved gable facing the street, a form that became fashionable in Dublin during the late seventeenth and early eighteenth centuries, largely through the influence of Huguenot and Dutch settlers who arrived in Ireland following the religious upheavals of the period. The name itself is thought to be a colloquial reference to King William III, William of Orange, under whose reign the style flourished. Where most Georgian redevelopment swept away these earlier buildings in favour of the flat-fronted brick terraces that now define so much of the city, a few Dutch Billies clung on, particularly in the older commercial streets south of the Liffey. Exchange Street Lower sits in precisely that kind of territory, a narrow street that retains traces of the pre-Georgian street pattern, tucked between the river and the area once defined by Dublin Castle and the old city walls.

The building has not been formally dated, which is part of what makes Scally's identification worth noting. Visitors to the area will find Exchange Street Lower running between Parliament Street and Fishamble Street, a short walk from the riverside. The gable end or roofline is the thing to look for; the stepped profile is the defining feature, and it reads most clearly when you stand back a little and look up rather than focusing on the ground-floor frontage. The street itself is quiet by Dublin standards and passes through quickly, so it rewards a slower pace than most people give it.