Number 42 is thought to be of the Dutch Billy type, a style of urban house that was once extraordinarily common in Dublin but has since almost entirely vanished from the streetscape. The Dutch Billy is recognisable by its tall, curved or stepped gable end facing the street, a form that arrived in these islands in the late seventeenth century and became fashionable among Dublin's merchant and tradesman classes. At a glance, such a house seems almost continental, and that impression is not entirely wrong.

The Dutch Billy style takes its name, somewhat loosely, from the period associated with William of Orange, though the architectural form has roots in the Low Countries and spread across northern Europe through trade networks and the movement of craftsmen. In Dublin, these houses proliferated during a period of considerable commercial expansion, lining the quays and the older street grid of the city south of the Liffey. Most were later demolished, replaced, or so thoroughly altered that their origins became unreadable. Number 42 Essex Street East was identified as a surviving example of this type by archaeologists Linzi Simpson and Ed O'Donovan in November 1997, who noted that the building could date from the late seventeenth or early eighteenth century. That cautious phrasing, "can date from," reflects how difficult it is to pin down an exact construction date without more invasive investigation.

Essex Street East runs between Parliament Street and Crampton Court, close to the old heart of the city near the former site of Dublin Castle's outer reaches and the area long associated with print, trade, and legal activity. The street is not especially prominent today, and the building itself does not announce its age. Visitors with an interest in early urban fabric should look at the roofline and upper storeys, where the gable form, if preserved, is most legible. The ground floor of a building like this will often have been heavily altered over the centuries, so the evidence tends to survive higher up. It is the kind of detail that rewards a slow walk and a willingness to look above the shopfront level, which is where most of Dublin's older building stock quietly endures.