Boomhall, Culmore Road, Londonderry, BT48 8JE

Boom Hall is a substantial ruined rural villa in Georgian style, built between approximately 1760 and 1779, set within a historically significant demesne on sloping ground above the River Foyle in the townland of Ballynashallog, on the northern edge of Londonderry. The house is noted within the Northern Ireland Parks and Gardens Inventory for the quality of its setting. Though fine in conception, the building was considered a little severe in its execution. It now stands roofless and without floors or internal finishes, but retains sufficient external architectural detail and form to tell the story of the house and its relationship with its surviving outbuildings, including the listed stable block. The building is considered of local interest.

The house is a large rectangular structure of two storeys on the entrance front, rising to three storeys on the side overlooking the River Foyle, where the ground falls away sharply. It is built of good random rubble schist with ashlar sandstone dressings, the sandstone probably quarried at Dungiven.

The entrance, or west front, is seven bays wide with a three-bay slightly projecting breakfront, symmetrically arranged. The walls of this breakfront are smooth rendered. A small single-storey porch with a side entry on the south side projects forward from the centre. This porch spans across the basement area, which forms a storey-height plinth running around the whole building. The porch has three-quarter engaged Roman Doric stone columns at its corners, with a deep frieze and cornice above and a flat roof. On the west side there is a single window opening, now built up, as are all the window openings on the basement and ground floor levels across the building. The ground-floor windows were formerly tall sash windows with multiple panes and ashlar sandstone trim. The first-floor windows are square in proportion, also with sandstone trim. A bold, well-moulded cornice runs around the full perimeter of the building at wall-top level.

The principal architectural feature of the house is on the east side, facing the river. Here there is a large polygonal bay rising the full height of the house, with similarly proportioned window openings on each facet. The central opening at first-floor level is enriched as an aedicule, with a moulded pediment, consoles, and fluted pilasters. On the north side is a smaller polygonal bay that defines the staircase position; this may have been a mid-19th-century addition. The south and north elevations are each five bays wide, with window proportions similar to those on the other facades.

The house enjoys a splendid view over the River Foyle and over the site where, in 1689, a boom was stretched across the river during the Siege of Derry, a circumstance from which the house takes its name. Two long avenue approaches served the house; the southern avenue had a gate lodge, now demolished, though its piers survive.

The breakfront design and its full-width steps suggest that a portico was originally planned for the entrance front but was never built. There are other seemingly anomalous features about the design, including an unusual internal layout, differences in room sizes, and certain inconsistencies that have led historians to speculate that the original plans were never fully resolved, or that the client or builder deviated from them during construction.

The house is attributed in the Dictionary of Irish Architects to the Derry-born architect Michael Priestley (died 1777), who also designed Prehen House, Lifford Courthouse, and the First Presbyterian Church in Magazine Street, Londonderry. However, the Boomhall Trust has argued on stylistic grounds that the design bears the hallmarks of Sir Robert Taylor (1714–1788), particularly his work at Sharpham Hall in Devon of around 1770, and has noted possible connections between Taylor and the Alexander family through the East India Company. Taylor had one known Irish commission — the addition of Assembly Rooms to the market house in Waring Street, Belfast, around 1775 — but no documentary evidence linking him, or any other architect, definitively to Boom Hall has yet come to light.

The house was created as part of a demesne assembled by James Alexander (1730–1802), a younger son of Nathaniel Alexander (1689–1761), an Alderman of the City of Londonderry. From the early 1750s until 1772 James had a successful career in the service of the East India Company, spending much of this time in the Indian subcontinent and accumulating a considerable fortune. He was created 1st Earl of Caledon in 1790. He married Anne Crawford of Crawfordsburn in November 1774, and in early 1776 bought the large Orrery estate at Caledon. Shortly afterwards he also acquired land in the townland of Ballynashallog, to the north of Londonderry, from his older brother Robert Alexander (1722–1790), who had been accumulating holdings in the area since the 1760s. A 19th-century Alexander family memoir suggests that some of these lands had been in Alexander hands earlier still, and that Nathaniel Alexander had lived in a previous house on the site also known as Boom Hall, which may have stood near the walled garden. Work on the new house appears to have begun almost immediately after the land was acquired, as the house is captioned on Taylor and Skinner's road map of the area surveyed in 1777. Following the death of James's wife Anne in childbirth in December 1777, James decided to settle with his young family at Caledon, and in 1779 handed the lease of the newly built house, offices, and lands of Boom Hall over to Robert, who appears already to have been overseeing the build.

For much of the 17th century the land had formed part of the Honourable the Irish Society's holdings, granted to that body as part of the Plantation settlement. In 1649 a star-shaped fortification known as Charles Fort was constructed on land to the south of the present grounds and was reused during the Siege of 1689 to guard the western end of the boom — its site has since been lost to road construction and housing development. A 1690 map drawn by Captain Francis Neville shows a small house with apparent outbuildings in the vicinity to the west of the fort, though little is known of this or of any dwellings that occupied the site before the later 18th century. There is also an unverified tradition that the wider area was once part of an estate known as Gunsland.

The house is recorded in the valuation of 1831 as measuring 71 feet by 56 feet by 28¼ feet in height, with a porch of 10 by 7 by 7 feet, the rear bow projection measuring 19 by 10 by 28¼ feet, a kitchen in the cellar measuring 71 by 38½ by 11¾ feet and 19 by 10 by 11¾ feet, a cellar store of 71 by 17½ by 11¾ feet, and two privies measuring 10 by 10 by 7½ feet and 8 by 6 by 6 feet respectively. The porch does not appear on the Ordnance Survey map of the previous year, 1830, suggesting either that it was omitted by the cartographer — not uncommon on some 19th-century Ordnance Survey maps — or that it was added to the building at some point in 1830–31. It does not appear on the revised map of 1848–52, though the polygonal bay addition to the north side is indicated on that map, along with two freestanding structures close to it. These freestanding structures are not shown on an estate map drawn up by R.H. Nolan & Co. in 1856, though the bay itself is undoubtedly earlier than 1856 as it is noted in the valuation of that year. The 1904 Ordnance Survey map shows the porch for the first time at that date, and also records a gasometer to the north of the house.

After Robert Alexander's death in 1790 the property remained with his wife Anne (née McCullough) until her death in 1817. It was subsequently leased to the Dean of Derry, Thomas Bunbury Gough (1777–1860), and from around 1835 to William Ponsonby (1772–1853), Bishop of Derry. In 1849 James Du Pré Alexander (1812–1855), 3rd Earl of Caledon, sold Boom Hall for £6,000 to Daniel Baird (1795–1862), a Castlefin-born merchant and ship-owner who had served as Mayor of Derry in 1847. After Daniel Baird's death in 1862 his widow Barbara leased the house to Joseph Cooke (1818–1896), a former business associate of her husband. On Barbara's death in 1879 the property passed to her grandson Daniel B. Maturin (1849–1924), who had assumed the additional surname Baird in 1875. According to the valuations he occupied the house from 1883 into the 1890s, though other sources suggest Cooke remained as tenant for much of this period. At some point in the mid-1890s, possibly shortly after Joseph Cooke's death in 1896, John Barr Johnston (1843–1919), a seed merchant and Mayor of Londonderry in 1897, became tenant. He is recorded in the 1901 census as occupying the house with his wife Isabel, their three children, and three domestic servants; the residence itself is described as a first-class house with 23 rooms occupied by the family. Johnston was followed around 1908 by timber merchant Henry J. Cooke (born 1852, son of the aforementioned Joseph Cooke), who in the 1911 census is recorded as living there with his wife Mary, their three young children, and five servants. After Henry Cooke's death in 1923 the tenancy passed to his son John Sholto Fitzpatrick Cooke (1906–1975), then a minor, while the freehold was inherited the following year by Charles Edgar Maturin Baird (1899–1994). In 1932 the property was leased to Michael Henry McDevitt (1894–1969), who appears to have been the owner or part-owner of M. McDevitt & Co.'s department store in Duke Street. During the Second World War the house and grounds were commandeered by the government and given over to the Women's Royal Naval Service. After the war Mr Maturin Baird attempted to restore the house before accepting an offer of £3,000 in 1949 from the tenant Mr McDevitt for both the house and 26 acres of the demesne; much of the remainder of the demesne was sold off during the following decade. Members of the McDevitt family continued to live at Boom Hall for a short time after Michael McDevitt's death in 1969, but the house was abandoned at some point in the early 1970s and was subsequently damaged by fire at some point before around 1976. In the early 1980s the southern third of the demesne was lost to the construction of Madam's Bank Road and the Foyle Bridge. Derry City Council purchased the remaining grounds in stages during the early to mid-1990s, acquiring the core of the site from a McDevitt relation in 1996. By this stage the house had been reduced to a ruined shell, in which condition it remains.