Hilden Mill, Mill Street, Hilden, Lisburn, Co Antrim, BT27 4RR

Hilden Mill, Hilden, Lisburn, Co. Antrim

Historical Background

Hilden Mill is one of the most significant surviving flax spinning and thread manufacturing complexes in Ulster, with origins stretching back to 1823 when William Barbour established a thread factory on a site previously occupied by an 18th century bleachworks run by Samuel Delacherois. Barbour was the son of John Barbour, a Scottish immigrant who had founded a small thread manufactory at the Plantation, Lisburn in 1784.

By 1837 the enterprise was described by Thomas Fagan, compiler of the Ordnance Survey memoir for Lambeg Parish, as "the most extensive thread factory in Ireland." Fagan's account gives a vivid picture of the early works: the water mill stood three storeys high and contained 20 thread mills each with 48 spindles for twisting thread, together with a double beetling engine of 12 beetles weighing 74 lbs each and two sets of rollers for yarn. All machinery was powered by a single breast waterwheel, 15 feet 6 inches in diameter and 6 feet broad, with a 7-foot fall of water drawn from the River Lagan. The buildings and bleach grounds covered 10 acres. Between 200,000 and 300,000 hanks of native yarn were spun annually into threads of every description, and upward of 200 people of both sexes were employed, earning between 3 shillings and £1 per week depending on age and experience. The 1835 Valuation records the three principal buildings as a water-powered thread mill measuring 71 feet by 25 feet and standing 22 feet high, a drying house of 43 feet by 21 feet by 26 feet, and a boiling house of 34 feet by 23 feet by 12 feet 6 inches.

In 1851 Barbour erected a substantial three-storey spinning mill comprising three contiguous buildings, powered by water and by two 45-horsepower steam engines made by Coates and Young of Belfast. Around 1861 these buildings were heightened by one and two storeys, a four-storey extension was added, and a new administrative office was built. These constitute the complex known today as the Old Mill. The rateable valuation at this point stood at £900, an exceptionally high figure for an industrial enterprise of the period.

Expansion continued virtually without interruption for the remainder of the 19th century, with the site's rateable value rising from £900 in 1861 to £1,650 by 1890. Two major phases drove this growth: first, the construction of the New Mill and ancillary buildings along the river, probably in the 1870s; and second, a major upgrade of the power supply in 1895, which involved the construction of a new steam engine house, boiler house and a 160-foot high octagonal brick chimney. The engines at that date produced a combined 2,050 horsepower, fed by seven boilers with two economisers. Coal arrived by barge along the Lagan Navigation, which ran alongside the premises on the Co. Down side of the river.

William Barbour died in 1875 and was succeeded by his sons John, Robert, Samuel, Thomas and Francis. In the early 1880s the firm became a limited liability company. Writing in 1888, George Bassett recorded that Barbours were by then the world's leading manufacturers of tailors' and shoemakers' sewing thread, with 30,000 spindles working on yarn spinning and a further 8,000 twisting yarn into thread. The site covered 45 acres, employed 300 people, and the firm operated spinning mills in nearby Dunmurry and Sprucefield as well as agencies and offices across Europe and America. Since 1864 they had also operated a spinning mill in Paterson, New Jersey. The Pictorial World of 1888–89 described the firm as "one of the great firms, not alone of Ireland, or even of the United Kingdom, but of the world."

Minor additions were made in the first two decades of the 20th century, including a large Belfast truss shed on the Island (the area between the river and the navigation) and a three-storey brick and concrete building on the main site. The next major phase of expansion came between approximately 1930 and 1960, with a finishing works on the Island and two large single-storey sawtooth-roofed spinning sheds on the main site, developments likely influenced by the Second World War and the post-war rise of synthetic fibres.

In the late 1970s the firm was acquired by the Hanson Trust and merged with Henry Campbell and Co. to form Barbour Campbell Ltd. Spinning was transferred to Campbell's Mossley Mill while Hilden concentrated on thread production. During the 1990s the centre of the main site was cleared for three large single-storey sheds into which twisting, finishing and making-up processes were transferred from the 19th century buildings. In 1999 Barbour Campbell was taken over by Coats Viyella. Thread manufacturing ceased in 2006 and the site was sold for redevelopment. It is currently recorded as derelict.

Architectural and Industrial Significance

The site is of outstanding architectural and historic interest. The scale, massing and floor configurations of the buildings — particularly those in Blocks 2, 3 and 4 — directly reflect the successive stages of thread production: hackling of raw flax, spinning it into yarn, twisting the yarn into thread, finishing by dyeing and waxing, and making-up by labelling and packing. The method of power generation is legible in the surviving boiler room, two engine houses and rope drive housings, and in the positional relationships between these buildings. Building materials vary by period of construction: basalt rubble was used in the mid-19th century, brick during the later 19th century, and concrete in the 20th century. Many buildings are richly embellished with decorative yellow brickwork to their quoins and eaves, and some carry carved figurehead keystones. Internally, the extensive use of brick jack arches throughout the mill floors reflects the structural requirement for fireproof construction capable of carrying heavy loads. The site's proximity to the Lagan Navigation reflects the historical necessity of importing coal and raw materials by water. Major phases of development are commemorated in date stones of 1851, 1861 and 1895. The complex represents one of the few flax spinning and thread manufacturing sites to survive in a largely intact state anywhere in the Province. The buildings also have group value with Hilden Mill Primary School and the Iron Lattice Bridge, both built nearby for the mill workers.

Site Organisation

For the purposes of this description the site has been divided into discrete blocks (numbered 1 onwards), each subdivided by its constituent buildings (lettered A, B and so on), with appendages differentiated further where necessary (for example 2D1, 2D2). The site lies on the left bank of the River Lagan immediately upstream of Hilden Bridge, with a portion extending into Co. Down on an island between the river and the Lagan Navigation. Most buildings with bowstring truss roofs are recorded separately under a companion listing record and are noted but not fully described below.

Block 1 — Former Store and Office Block

This block comprises a multi-pile masonry building at the east end (1A) and a more recent brick building at the west (1B). Building 1A was extant by 1901 and almost certainly dates from the 1880s, when Mill Street — along which it is aligned — was laid out in 1879. Building 1B dates from the mid-20th century.

Building 1A is a five-pile, single-storey store aligned north-south along the site's northern boundary. It has a five-bay natural slate roof with fretted bargeboards and finials at the south ends, and half-round metal gutters. The south elevation is of brick, with all openings having semicircular heads trimmed with yellow brick. Each of the five gables on the south elevation contains either a multi-paned window or a doorway with a multi-paned overlight; the windows have sandstone cills. Some openings are now infilled and all doors are missing. The east elevation is also of brick and was originally a party wall with a now-demolished adjoining building; an interconnecting doorway survives at its south end with an original metal I-beam head. The north elevation appears to have been the original rubble masonry boundary wall, its top raised in brick to form gable apexes. Square-headed window openings were inserted through this wall but are now all infilled. Surviving fittings: timber casement windows; cast-iron rainwater goods.

Building 1B is a single-storey office with a bituminised flat concrete roof carrying a raised skylight. The walls are of brick, rendered to the west elevation, with square-headed openings and concrete heads. There is a door on the south elevation and metal-framed casement windows to the south and east sides, all with concrete cills. All openings on the north side have been infilled. Rainwater goods are missing; doors are missing.

Block 2 — Old Mill

This block contains an assortment of one- and two-storey offices, four- and five-storey mill buildings, a steam engine house and various smaller structures, ranging in date from 1851 to the mid-20th century.

Building 2A is a two-storey building at the north-west corner of the block, dating from 1861, with its principal façade facing west. It has a double-pile hipped natural slate roof, now partly stripped. The walls are of brick, rendered and painted to the west and north elevations, and painted only to the east. The west and north elevations are embellished with moulded stucco string courses at ground-floor and first-floor cill levels and between the floors, and both have bracketed cornices with dwarf blocking walls above. Four tall rendered chimney stacks stand over the eaves on the west side, all now defunct. Ground-floor openings have segmental heads; first-floor openings have square heads. The five-bay west elevation is symmetrically arranged: a central entrance doorway at ground floor has a bearded figurehead above its segmental-headed overlight, flanked on each side by two 1-over-3 top-opening windows with bracketed moulded cills and raised stucco keystones. Five regularly spaced 2/2 sash windows light the first floor, each with bracketed squared cills. All openings have stucco architraves and are set in slightly recessed panels. The three-bay north elevation is identical in design except that the central ground-floor opening is a window rather than a door, also embellished with a bearded figurehead; cast-iron wheel guards are fixed at each corner. The east elevation is by contrast extremely plain — painted brick with a projecting chamfered brick eaves course carrying ogee cast-iron gutters. Most ground-floor openings are infilled; five 2/2 sash windows survive to the first floor, the left-hand one modified to a doorway into Building 2B. Surviving fittings: ogee cast-iron gutters; timber sliding sash windows.

Building 2B is a mid-20th century single-storey block abutting the ground floor of 2A and part of 2D. It comprises three sections: offices (2B1), toilets (2B2) and a staircase (2B3). The office and toilet sections have flat felted concrete roofs with raised concrete verges and skylights, the office roof slightly higher than the toilet roof. The staircase has a monopitched natural slate roof (slates stripped). All walls are of brick with squared concrete-headed openings; windows have timber or metal frames with concrete cills.

Building 2C is a three-storey over basement mill building, its gabled façade facing west, with a datestone confirming construction in 1861. A later goods hoist (2C1) abuts its south-west corner. The building has a pitched natural slate roof with ogee cast-iron gutters. The basement, ground and first-floor walls are of rubble basalt with painted sandstone quoins to the west gable; the second floor is of brick with yellow-painted red-brick quoins. All openings are decorated with yellow-painted brickwork. The west gable has a dentillated brick string course along the tops of its second-floor windows; the apex carries a chevroned yellow-brick string course at its base and a moulded brick cornice along the verges. An ashlar sandstone string course at second-floor window cill level continues around the north and south sides of the building, and further around to serve as the parapet coping of 2A and the cill course to the third-floor windows of 2D and 2F.

The ground floor of the west gable has a wide segmental-headed doorway containing a three-leaf timber door with elongated semicircular overlights; a bearded head above the apex of this opening carries the date 1861. The doorway is flanked by figurehead-embellished windows with stone cills. Three square-headed window openings light each of the upper floors, with tripartite arrangements to the central openings: on the first floor these are margined 2/2, 4/4 and 2/2 sliding sashes with 2/2 sashes at the ends; on the second floor the end windows of the tripartite set are margined 4/4 sashes and the central window is missing, with margined 4/4 sashes at each end. In the gable apex is a spoke-margined 4/4 sash window in a semicircular opening trimmed with dentillated yellow brick.

The north elevation is partly abutted by the office block (2A). The exposed west end is rendered and painted to match 2A's façade, with a segmental-headed window at ground floor and a square-headed window at first floor, both detailed as those to 2A; the ground-floor opening carries a figurehead to its apex. The top floor, which rises above the roofline of 2A, has a chevroned yellow-brick string course and a moulded brick eaves cornice, and is lit by five windows — four 3-by-4-pane sashes and one 8/8 sash. The east gable is abutted by the slightly narrower and lower Building 2D. The south elevation, partly obscured by the goods hoist tower at the left, has four exposed upper openings with 3-by-4 and 5-by-8 top-opening windows, and carries the same chevroned string course and cornice detailing as the north side.

The goods hoist, 2C1, post-dates 1922. It is of brick with a moulded stucco eaves cornice below a dwarf blocking course around a flat concrete roof. Openings to the upper floors are segmental- and square-headed, generally with 2-by-3 windows with stone cills.

Building 2D is a four-storey mill building aligned east-west. The ground, first and second floors were probably erected around 1851 and the building raised to four storeys in 1861. It is abutted along its south elevation by a staircase (2D1), on its north elevation by a toilet stack (2D2) and goods hoist (2D3), and on its east gable by a further toilet stack (2D4). The staircase and toilet stacks probably also date from 1861; the goods hoist was added between 1910 and 1916. The building has a pitched natural slate roof with half-round metal gutters. The walls of all but the top floor are of painted random rubble; the top floor is of painted brick with an ashlar sandstone cill course between it and the second floor on exposed elevations. All openings have shallow segmental heads trimmed with brick, and the windows have stone cills.

The 16-bay north elevation is partly abutted by Building 2E, goods hoist 2D3 and toilet stack 2D2. Window types vary by floor: 3-by-4 top-openers to most floors, 2-by-3 top-openers to the first floor and 6-by-8 to the top floor. The three-bay east gable is partly abutted at ground floor by a single-storey lean-to, above which toilet stack 2D4 rises the full height. The 13-bay exposed section of the south elevation has similar detailing, with 2-by-3 top-openers to the first floor, 3-by-4 top-openers to the second floor, and a mixture of 3-by-4 top-openers and 6/6 sliding sashes to the third floor.

The staircase, 2D1, serves all floors with half-landings between each. Stairs are of concrete, landings are supported on metal beams, and a plain timber handrail runs up the inside wall. The doors into 2D are of timber except for the topmost, which is a metal-sheeted fire door. A small store occupies the head of the stairwell. Multi-paned window openings with segmental, semicircular and square heads light the landings and half-landings.

The toilet stack 2D2 is a small semicircular brick projection on the north elevation, rising to the top floor. On each floor two small toilet cubicles are cantilevered one to each side of the brick spine (with only one at ground level). They have monopitched concrete roofs and brick walls on cantilevered metal beams, lit by single 2-by-2 windows. Their concrete and metal construction indicates they are 20th century additions to the original brick spine. Each cubicle retains its glazed tiling, bowl and overhead cistern.

The goods hoist, 2D3, is a square brick tower 4½ storeys high abutting the corner of 2D and 2E, serving both buildings. It is embellished with a moulded yellow-brick cornice below a flat concrete roof with blocking wall. Segmental-headed windows light all floors — 3-by-4-pane except at the top floor where they are 3-by-3. External access is at ground level with internal access to all floors of both 2D and 2E. The electrically powered hoist mechanism survives in situ but is no longer operable.

Toilet stack 2D4 is similar to 2D2 but has a monopitched roof and only one cubicle per floor (the first-floor cubicle has been removed). A 20th century single-storey addition wraps around it at ground-floor level.

Building 2E forms part of the companion listing record and is not described here.

Building 2F is a four-storey mill building located between 2D and 2H along the left bank of the Lagan. It was erected as a three-storey mill around 1851 and raised to four floors in 1861. Although it has a bowstring roof, it is described here as it is not included in the companion record. The roof is a shallow felted bowstring truss. Except for the top floor, the walls are of painted random rubble; the top floor is of painted brick, with a sandstone cill course on exposed elevations. All openings have shallow segmental heads trimmed with brick; windows have stone cills.

Both the east and west elevations are nine bays wide. On the east side the ground floor contains 6/6 sash windows; the first floor has 2-by-3 top/bottom-openers and the remaining floors 3-by-4 top-openers. The southernmost window on each floor has been enlarged to form a fire exit to an external steel staircase. On the west elevation, ground-floor frames have been removed and openings sheeted over; first-floor openings are brick-infilled; the second floor has 3-by-4 top-openers; the top floor has a mixture of 2-by-3 top/bottom-openers and 6/9 sashes. Rainwater goods are missing.

Building 2G is a five-storey mill building aligned east-west with its principal façade facing west, added to the west gable of 2H in the period 1888–1901 (most likely 1895, as discussed under Building 4E). That it is an addition is clear from the discontinuity in the coursing of its yellow-brick quoins relative to the brickwork on the north and south elevations of 2H; in making the addition, the original gable of 2H was dismantled to allow the floors of the two buildings to connect. A goods hoist (2G1) and toilet stack (2G2) abut the north side, both added between 1910 and 1916. The building has a pitched natural slate roof with continuous glazing to both pitches and ogee cast-iron gutters to the north and south elevations. The west end is slightly higher than the rest of the building and is surmounted by a large cast-iron water tank in place of a slate roof; the front of the tank is painted with the words "Barbour Threads Limited" and the Red Hand of Ulster — the company's trademark — and both ends read "Ahead in Thread."

The walls are of red brick with yellow-brick quoins. The eaves have several courses of yellow brick below a dentillated and moulded yellow-brick cornice. A sandstone cill course runs at third-floor window level; windows at this level have stone cills, but all others throughout the building have cast-iron cills. The three-bay west gable has two concrete-headed doorways inserted at ground floor. Upper floor openings have shallow segmental heads; the top floor has 2-by-4 windows and other floors 2-by-3, all top/bottom-opening. Three cast-iron bearing housings are fixed along the ground floor with two to the first floor and one to each floor above, indicating that this end formerly housed rope drives transmitting power from the engine house to each floor. A cast-iron wheel guard at the left end of the ground floor bears the maker's name "Ritchie Hart and Co., Belfast."

The eight-bay north elevation has a slightly advanced bay at the right-hand end; a goods hoist (2G1) abuts the second opening from the right, and a toilet stack (2G2) stands between the fifth and sixth openings. The exposed section has 2-by-3 top/bottom-opening windows; those to the second bay from the left have been broken out in recent times to remove machinery. The east end is abutted by the slightly narrower Building 2H; the exposed wall section is slated. The south elevation has a slightly advanced bay at the west end; four bays from the left are abutted by the two-storey engine house (2J). A two-storey building formerly abutted the ground, first and second floors here but has been removed. All exposed floors on this elevation have 2-by-3 top/bottom-opening windows in shallow segmental-headed openings.

Goods hoist 2G1 is a rectangular six-storey brick structure serving all floors including the attic. Wall breaks confirm it is an addition. It has an ashlar sandstone cill course at third-floor level and a dentillated and moulded brick eaves course around its flat roof. Each upper floor on the north elevation has a 1-by-3 window in a shallow segmental-headed opening. Access was at ground level (now filled by a ventilation duct); the hoist itself has been removed.

Toilet stack 2G2 is a small square six-storey brick structure serving all floors including the attic, with a dentillated and moulded yellow-brick cornice. Access balconies from the mill floors serve each level at the west end; these have concrete floors and timber-sheeted walls. Each cubicle is lit by a small rectangular window on the north elevation.

Building 2H is a five-storey plus attic building aligned east-west at the east end of 2G, last described as No. 1 Polishing. A datestone on the north elevation records that its bottom three floors were erected in 1851; by 1861 it had been raised to its present five storeys. A staircase (2H1) abuts the north elevation and three toilet stacks (2H2, 2H3, 2H4) abut the south side, all probably dating from 1861. The building has a pitched natural slate roof with continuous glazing to both pitches and ogee cast-iron gutters.

The ground, first and second floors are of painted rubble basalt with brick quoins to the east gable; the top two floors are of brick, with a sandstone cill course between the second and third floors on all exposed elevations. The eaves are embellished with courses of yellow brick below a dentillated and moulded yellow-brick cornice. A vertical break in the stonework at the east end of the south elevation, together with the remnant of a brick quoin to its left, indicates that the easternmost bay was added to an existing building before both sections were topped with two floors of brick — a development that took place between 1851 and 1861.

The 20-bay south elevation has a five-storey semicircular toilet stack (2H2) between the eighth and ninth openings from the left, a similar stack (2H4) between the 15th and 16th openings, and a rectangular six-storey stack (2H3) at the 11th opening. Buildings 2J and 2K abut the ground floor at its east end; a two-storey building formerly abutted here has been removed. Most windows are 2-by-3 top/bottom-openers; the remainder are later replacements. The north elevation has an 1851 datestone between the two right-hand first-floor windows. The east gable is five bays wide, with its lowest three floors added to the end of the main block before both were raised together. Openings have shallow segmental heads trimmed with brick; the ground floor has 2/4 sash windows, first and second floors have 2-by-3 top/bottom-openers, floors above have 3-by-3 top/bottom-openers, and the attic openings have semicircular heads, the central one serving as a fire escape door to a metal staircase shared with 2F.

Staircase 2H1 is a semicircular staircase abutting the third opening from the right of the north elevation, rising to the attic floor. It has a flat concrete roof and brick walls; eaves are detailed as the main building. Spoke-headed 1-by-3 windows light both sides at each floor level, with smaller round-headed windows between landings. Internally the stair winds continuously between landings without half-landings; the stairs are of concrete supported on metal beams, with a tubular steel handrail on the outer wall. The inner column of the stairwell is hollow and carries pipes and cables.

Toilet stack 2H2 is a semicircular brick projection rising to the eaves, similarly decorated with yellow brick, with small vertical ventilation slits. It survives as an empty spine without projecting cubicles. Toilet stack 2H3 is a rectangular brick structure rising six floors, with a dentillated yellow-brick eaves course around its flat roof and square-headed 2-by-3 top/bottom-opening windows with flat concrete heads to each floor. Toilet stack 2H4 is identical to 2H2 except that a cubicle projects to the left from the spine on each floor; each is supported on a cantilevered metal beam and has concrete walls.

Building 2J is a two-storey over basement engine house aligned east-west at the left end of the south side of 2G. The absence of any wall break with 2G on their shared west gable indicates they were built at the same time, in the period 1888–1901 (most likely 1895). The building has a hipped natural slate roof with cast-iron down pipes, and its walls are detailed identically to 2G — red brick with yellow-brick quoins, and eaves cornices running under a yellow-brick blocking course coped with moulded ashlar sandstone, which continues as a cill course around the west gable of 2G and south elevation of 2H. All windows have cast-iron cills.

The west gable has two flat-concrete-headed doorways (later inserts) at ground floor, above which are two spoke-headed timber windows, originally 3-by-3, now partially infilled with brick at the bottom. The south elevation has two large spoke-headed and margined 3-by-4 timber windows. A cast-iron wheel guard at the left end of the ground floor is inscribed "D and W Grant, York St, Belfast." On the east gable, stone steps lead up to a semi-glazed three-leaf timber door with raised and fielded panels (now missing); directly above it is a large spoke-headed 4-by-2 window, now obscured by a later slatted ventilation panel.

Building 2K is a single-storey mid-20th century building abutting the south-east end of 2G. It has a pitched profiled asbestos roof with glazing and plain timber bargeboards and ogee cast-iron gutters. The brick walls have advanced brick eaves and all openings have squared concrete heads. There is a door on the west gable and five 4-by-4 steel-framed windows along the south side with concrete cills and shallow pilasters between.

Building 2L abuts the corner of 2G and 2K and was erected between 1910 and 1916. It has a felted bowstring truss roof, now partly collapsed, with boxed eaves and a raised skylight; rainwater goods are missing. The walls are of brick; the east gable appears to have been built over an existing basalt rubble wall. The south elevation has a sliding timber door to the centre flanked on each side by a segmental-headed 8/8 sash window with stone cills. There is a 2-by-2 window to the east gable. Although there is no wall break with 2K, the south elevation runs at a slight angle to it.

Building 2M is a single-storey infill building between 2D, 2F and 2H, erected in the period 1861–1888, replacing earlier structures recorded in the 1861 valuation, and described in a 1996 plan as No. 1 Making Up. Its roof comprises six sawtooth bays, glazed to their north pitch and slated (now stripped) to the shallower south slope, with concrete verges at the west end; rainwater goods are missing. The west wall is of roughly-faced and coursed basalt blocks with cement-rendered brick gable apexes, containing segmental-headed brick-trimmed door and window openings. There are two now-infilled window openings per roof bay, all with stone cills. All other elevations make use of the walls of adjacent buildings.

Block 3 — Boiler House

This block comprises a double-pile two-storey boiler room (3A), a small two-storey building to its north-east (3B) and a single-storey section along its east side (3C). All three buildings date from the period 1888–1901, almost certainly from 1895 and built at the same time as Buildings 2G and 2J. They were associated with a now-demolished 160-foot high octagonal brick chimney that formerly stood just south of 3C. Modern oil tanks to the south (3D) have since been removed. A late 19th century dye house to the south, only a gable of which now remains, is noted as 3E.

Building 3A housed boilers at ground-floor level that generated steam for the engines in Building 2J; the first floor was used as a drying room for hanks of yarn. This double-pile building has hipped natural slate roofs with raised ridge ventilators; pipes project through the north end of the roof into the first floor of the engine house and the top floor of 2G. A tall circular metal chimney rises from the south end of the west pile. Ogee cast-iron gutters. The walls are of brick with yellow-brick quoins and dentillated yellow-and-red brick eaves.

The seven-bay west elevation has six large semicircular window openings at ground floor, three retaining their 4-by-3 timber frames; all have round-edged cast-iron cills. The semicircular-headed doorway at the right-hand end has been enlarged with a flat concrete head and slatted doors inserted to provide access to modern natural gas control equipment. Seven segmental-headed windows to the first floor all have 6-by-4 cast-iron frames and squared cast-iron cills. The five-bay north elevation forms a continuous façade with Building 3B. At ground floor there is a semicircular-headed doorway with slatted timber doors (later inserts) at the right, and a narrower segmental-headed doorway with overlight into 3B at the left; three modified segmental-headed windows occupy the space between. At first-floor level a diagonally-sheeted loading door at the centre (formerly leading to a balcony accessed from the old dye house) is flanked on each side by two windows detailed as those on the west elevation's first floor. A cast-iron wheel guard at ground level at the left end of this elevation is inscribed "D and W Grant, York St, Belfast." The east elevation is abutted to both storeys at the right by Building 3B and at ground floor level by 3C; the exposed first-floor section has five windows detailed as the west elevation. The four-bay south elevation has a large semicircular-headed window at ground floor left and three smaller segmental-headed 6-by-4 windows; the first floor has two windows and two loading doors.

Building 3B is contemporary with 3A (no wall breaks), sharing its hipped natural slate roof, ogee cast-iron gutters and brick walls with yellow-brick quoins and eaves detailing. Its north elevation is continuous with that of 3A as already described. The east elevation has two cast-iron windows at ground floor (6-by-4 and 6-by-3) and one at first floor (6-by-4). The right half of the ground floor was formerly abutted by the old dye house, of which only a fragment of walling survives. The south gable is abutted at ground floor by 3C; the first floor of this gable has a segmental-headed 6-by-4 cast-iron window.

Building 3C is contemporary with 3A and 3B (no wall breaks), abutting their shared corner. It has a sarked monopitched natural slate roof behind a low brick blocking wall. The walls are of brick with plain quoins and eaves. The five-bay east elevation has a door at each end with three 6-by-4-pane cast-iron windows between; a 6-by-6 window lights the south gable. Rainwater goods and doors are missing.

Section 3D comprised three horizontally-mounted cylindrical oil tanks to the immediate south of 3A, enclosed within a concrete block bund faced with a texture coloured to resemble sandstone. The tanks became redundant when the boilers converted to natural gas in 1999 and have since been removed.

Building 3E is the surviving fragment of a late 19th century dye house, extended in the early 20th century, which abutted the boiler house block and the lower floors of Mill 2H. According to the valuation books it was single-storey with a felted roof. It was demolished sometime after 1988, leaving only a remnant of brick walling at its east end overlooking the river; this section has a segmental-headed 3-by-4 top-opening window at its south end.

Block 4 — New Mill

Building 4A is a small single-storey over basement building at the north-west end of the block, dating from the period 1888 to 1901, latterly used as part of the thread polishing department. The roof was originally of natural slate but has gone. Ogee cast-iron gutters. The walls are of red brick with yellow-and-red brick quoins at the north-west and advanced yellow-brick eaves; all openings are also trimmed with yellow brick. The five-bay north elevation has timber-framed windows throughout: the central opening contains a 5-by-4 window with a concrete cill, the others are 8/8 sashes with painted timber cills. The west gable has a 2-by-3 window in a round-headed opening with a concrete cill.

Building 4B is a single-storey building over a basement, aligned north-south between Buildings 4A and 4H, erected sometime between 1861 and 1888 (possibly the 1870s), and latterly part of the polishing department. It has a flat leaded timber roof around a large hipped skylight. The basement walls are of pocked cement render coloured to mimic sandstone, with a moulded base course below; a moulded sandstone string course runs above the basement. The upper walls are of ashlar sandstone embellished with a rope-moulded string course and moulded stone cornice below a roof blocking course. The roof is accessible from the first-floor landing of the adjoining staircase (4H2).

The three-bay west elevation has segmental-headed basement openings with dressed stone voussoirs and projecting keystones; two contain slatted vents and one a casement window with a small fire escape door. The upper half of the wall has a semicircular-headed central doorway with a moulded stone architrave and surviving spoke-headed overlight (door missing), flanked to each side by a blind segmental-headed panel with a moulded architrave. Each doorway and recess has a projecting figurehead to its keystone. The left end of this elevation is slightly advanced with a blind rectangular panel. The three-bay north elevation, whose basement is abutted by Building 4A, has three segmental-headed window openings with moulded architraves and 3/1 top-opening timber windows, each with animal-head keystones — from left to right a boar, a lion, and an elephant. The left and right ends of this elevation are slightly advanced with blind rectangular recesses.

Building 4C is a five-pile, three-storey building aligned east-west along the north side of 4H, connected to the main mill by an overhead corridor (4C1); both components date from the period 1888–1901 and were last used as part of the polishing department. Each pile has a pitched natural slate roof. Ogee plastic gutters. The walls are of lined and cement-rendered brick.

The five-bay east gable (one bay per pile) is partly abutted at ground floor left by 4D. Two remaining openings are large semicircular recesses with smaller 3-by-3 windows; a third has a sheeted timber door. Five smaller semicircular-headed openings to the first floor each have 5-by-3 windows with timber cills; second-floor openings are segmental-headed with 3-by-2 windows and timber cills. A small toilet is cantilevered from the second bay at second-floor level. The seven-bay north elevation has square-headed openings to the ground and first floors, and shallow segmental openings to the top floor; all contain 2/4 timber sash windows with stone cills (no cills at ground floor). Fire escape doors serve the upper two floors via an external staircase at the right-hand end; the openings served by this staircase are original. The west gable is partly abutted by 4A and 4B; the exposed sections of ground and first floors are blank; the second floor has 2/6 top-opening windows with timber cills. The south elevation has three square-headed ground-floor openings now infilled, with three 2/4 sash windows to each of the first and second floors, all with stone cills.

The linking passage, 4C1, connecting the first floor of 4H to Building 4C, has a pitched natural slate roof, partly glazed timber walls, and a timber floor supported on metal beams.

Building 4D is a single-storey building at the north-east corner of the block, aligned east-west, built sometime between 1931 and 1938. Its sawtooth roof has three bays, all glazed to their north pitches and clad with profiled asbestos sheeting to their south pitches; the roof apexes are braced to each other with exposed steel beams. Ogee cast-iron gutters. The east elevation is raised in brick over an existing rubble basalt wall, with a narrow round-headed brick-trimmed opening at its centre. The five-bay north elevation is of brick throughout; there are sheeted timber doors at each end and three 4-by-4 metal-framed windows with concrete heads and cills between. The remaining elevations make use of the walls of adjacent buildings 4C and 4H.

Building 4E is a two-storey building added to the west side of the stairwell (4H2) at the north-west corner of the block; a datestone at the apex of the west gable records 1895. Architecturally the building has the appearance of an engine house, and although no surviving boiler room has been identified elsewhere in this block, motive power would have been required for the machinery in 4H. It is likely that steam was supplied from the nearby Block 3, which supports the inference that Block 3, and by extension Buildings 2G and 2J, were all also erected in 1895 — a dating further corroborated by the shared yellow-brick detailing common to all these buildings. The building is accessed internally from a small door at second-floor landing level in the adjoining staircase (4H2).

The building has a hipped natural slate roof, now partly stripped with artificial slate repairs. The walls are of red brick over an advanced basal course coped with black brick, embellished with yellow-brick quoins, a string course, dentillated frieze and moulded cornice, all in yellow and red brick. All openings have semicircular heads. The three tall openings on the north elevation were originally single openings but when the interior was divided into ground and first floors a concrete cill was inserted at the new first-floor level; the upper window is a spoke-headed 1-by-4 timber sash and the lower is a square-headed 4-by-3 top-opener. The west gable has a tall opening at the base containing a sheeted timber entrance door with sidelights, slightly above external ground level and originally accessed by an external staircase (now gone); above the door is a spoke-headed 6-by-3 window shared between both floors, and above that the datestone "1895" in bas-relief. The south elevation is obscured at ground floor by Building 4F and on the right by 4G; the exposed upper section has two spoke-headed 1-by-4 windows shared between both floors.

Building 4F is a single-storey office built between 1920 and 1962, aligned east-west in the corner formed by 4E and 4G; wall breaks confirm it is later than both. The sky-lit natural slate roof is hipped at its east end with plain boxed eaves and bargeboards; half-round plastic gutters. The walls are of red brick without yellow-brick embellishment; all openings have square concrete heads. The three-bay west gable has a sheeted timber doorway at the centre and a timber casement window with concrete cills to each side. There are no openings on the south elevation.

Building 4G is a three-storey building on the west gable of the mill (4H), in the corner formed between it and the goods hoist 4H1. It was most probably built to house the rope drives from the engine room (4E) to the mill (4H), serving the same function as the west end of Building 2G, and is therefore also likely to date from 1895. The building has a flat concrete roof accessible from the mill's top floor. The walls are of red brick with yellow-brick quoins and a yellow-and-red-brick string course, dentillated frieze and moulded cornice to the blocking wall around the roof. The west elevation and north elevation each have 3-by-3 timber-framed windows with shallow segmental heads and cast-iron cills at the appropriate floor levels.

Building 4H is a four-storey over semi-basement mill, aligned east-west, 18 bays long by four bays wide, built in the period 1861–1888 (probably the 1870s) and latterly used for thread twisting. It is abutted at the west by a goods hoist (4H1), and on its north side by a staircase (4H2), goods hoist (4H3) and toilet stack (4H4). The staircase and toilet stack are contemporary with the mill; the goods hoists date from the 1910s (4H1) and later (4H3). The building has a pitched corrugated asbestos roof with continuous glazing along both pitches, replacing the original felt roof. Ogee cast-iron gutters. The walls are of rubble basalt throughout with brick quoins; all openings have shallow segmental heads trimmed with brick, and all windows have stone cills.

The north elevation is abutted by the staircase (4H2), goods hoist (4H3), toilet stack (4H4) and Building 4D. Most ground-floor openings contain 2-by-8 top/bottom-opening windows, with some possibly earlier 6-by-7-pane windows also present. First and second floors have 2-by-4 top/bottom-openers; third floor has 2-by-3 bottom-openers. The west gable is abutted by the goods hoist (4H1) and offices (4G); the exposed section has a brick apex with a moulded stone string course separating it from the rubble masonry below, which is a continuation of the moulding along the wall heads of the north and south elevations. The verges of the apex are painted yellow; there is a 3-by-3 circular window with dragon-teeth yellow-brick and yellow-painted red-brick trim; the top floor has 2-by-3 and 3-by-4 windows with stone and concrete cills. The south elevation is partly abutted by Buildings 4J, 4K and 4L, with windows in a variety of styles: 2-by-8 top/bottom-openers at ground floor, 3-by-5 top-openers at first floor, 2-by-4 top-openers at second floor, and 2-by-3 bottom-openers at third floor.

Wall breaks show the original mill was extended lengthways by one bay at its east end. This added bay is the same height as the main block and five bays wide; because it has a flat roof, the apex of the original gable is left exposed, showing three semicircular-headed windows (3-by-3 and 3-by-4-pane). The added section has a flat felted timber roof. Its walls at basement, ground and first-floor levels are of basalt rubble; the top two floors are of red brick. The footprint of the rubble section appears on the 1901 Ordnance Survey map; valuation books indicate the structure had reached its present height by 1922 at the latest. The entire addition has yellow-painted quoins and a continuous masonry cill course at second-floor level; openings have shallow segmental heads with stone cills. Ground-floor and upper openings have 4-by-3 windows, 2-by-4 top/bottom-openers and 2-by-3 top/bottom-openers respectively. A small monopitched corrugated-asbestos shed abuts the left-hand end of the basement.

Goods hoist 4H1 is a later addition (1910–16), running up the third opening from the left on the west gable; wall breaks confirm it is later, though the mill's original openings may indicate an earlier unenclosed hoist preceded it. It has a flat felted timber roof, red brick walls with a yellow-and-red-brick platband and dentilled cornice around a stone-coped blocking wall. Most window openings have been sheeted over, but 1-by-3 windows survive on the south and west elevations.

Staircase 4H2 is a four-storey rectangular staircase abutting the two right-hand openings on the north elevation, built at the same time as the mill and probably contemporary with Building 4B. It has a hipped natural slate roof with skylight and ogee cast-iron gutters. The walls are of red brick with a continuous cill course to each upper floor; quoins, moulded brick eaves and opening surrounds are painted yellow. The north elevation at ground floor is detailed as the west elevation of Building 4B — ashlar sandstone over a stucco basal course with moulded string courses and moulded eaves. Above the square-headed entrance door is a segmental-headed recess containing a smaller 4-by-1 overlight with a moulded cill and architrave and a projecting figurehead to the keystone. Upper windows generally have segmental heads, though some are round- or square-headed; several have been wholly or partly infilled; surviving windows have various fenestration patterns of 2-by-2, 3-by-2, 6-by-6 and 6-by-8 panes.

Goods hoist 4H3 is probably of mid-20th century date, extending from the ground floor to above the eaves on the tenth opening from the right on the north elevation. It is a steel-framed structure clad in corrugated metal; the mill windows were enlarged to facilitate access. It serves both 4H and 4C, and the electrically-powered hoist mechanism is accessed by a metal ladder from the mill's top floor.

Toilet stack 4H4 is a narrow semicircular stack rising the full height of the building between the 14th and 15th openings from the right-hand end of the north elevation. Cantilevered reinforced-concrete platforms on the west side of the stack provide access from each floor of the mill into the toilet cubicles within.

Building 4J is a 10-pile, single-storey over semi-basement building at the south-west corner of Block 4, dating from the period 1936–1962 (probably the 1950s), latterly used for synthetic thread twisting. The four northernmost piles project eastward beyond the general building line; a contemporary single-storey building (4J1) abuts the east end of these longer piles. The roof is of sawtooth profile, glazed to the north pitches and clad with profiled asbestos to the south pitches; the apexes are braced with exposed metal beams; verges are slightly raised at the east ends with a concrete-coped blocking course along the west. Ogee cast-iron gutters. The walls are of red brick with yellow-brick quoins; all openings have square concrete heads and concrete cills.

The west elevation has 14 blind recesses at the top of which are louvred vents or small windows with concrete heads and chamfered-brick cills, plus a doorway at the right end; above the recesses is a patterned yellow-and-red-brick platband and a moulded yellow-brick eaves course. The north elevation is almost entirely devoid of openings save for a 1-by-2-pane window at the west end; a triple-pile sawtooth roof canopy extends across the west side of 4G and 4H1, and a small monopitched infill bay occupies the space between the canopy and the mill. The exposed east end has a chamfered brick course between the basement and slightly inset ground floor; the basement is exposed on the east elevation, with a sheeted timber doorway at the left covered by a felted bowstring truss canopy on a steel frame (recorded separately). There are 4-by-3 metal-framed windows to both floors. The right-hand half of the basement is abutted by the single-storey flat-roofed Building 4J1. Window openings on the south elevation have 4-by-2 metal frames, all now sheeted over; those to the upper floor are later inserts.

Building 4J1 is a single-storey building at basement level, contemporary with 4J. It has a flat bituminised concrete roof with a hipped skylight. The walls are of brick; a small first-floor toilet at the south-west corner is accessible from 4J's upper floor. A linking corridor on top of the roof connects that floor to the first floor of 4K. Access is from a doorway on the south gable (with a 1-by-3 overlight) and from the ground floor of 4K. The interior has a concrete floor and painted walls; it was last used as a mechanics' workshop.

Building 4K is a three-storey building built between 1910 and 1916, aligned north-south in the corner between 4H and 4L, 11 bays long by three bays wide. It has a flat bituminised concrete roof with a felted timber lean-to enclosing a water tank near the north end. Ogee cast-iron gutters. The walls are of reinforced concrete with red brick facings; all openings have square concrete heads and all windows are 3-by-4 timber-framed with concrete cills. The west elevation is abutted at ground floor by 4J1; there is a fire escape door at the right end of the second floor. The south elevation is abutted at ground floor by 4M1.

Building 4L is a five-storey building aligned north-south at the south-east corner of 4H, infilling between 4H and 4M, probably dating from the 1870s or early 1880s (it was visible in a view published in 1888). It is 13 bays long by three bays wide. Although it has a shallow felted bowstring truss roof (16 trusses), it is described here as it is not included in the companion record. The walls are of brick throughout; the south gable apex appears to have been rebuilt with newer brick. Toilet stacks at the south-east (4L1) and south-west (4L2) corners abut the building; 4L2 is contemporary with the mill, but 4L1 is a 20th century replacement of an earlier one. All openings have shallow segmental heads and the windows have stone cills.

The east elevation has a variety of window styles: 8/8 sashes at ground floor, 6/12/6 sashes at first and second floors, 3-by-4 top-openers at third floor, and 4-by-2 top-openers at fourth floor; toilet stack 4L1 runs up the left-hand end. The south gable is abutted to its lower three floors by 4M; the exposed section has 2/2 and 3/3 sash windows at third floor and three infilled openings at the top. The west elevation is abutted on all but the two right-hand bays at the lower three floors by Building 4K; toilet stack 4L2 is at the right-hand end. Fire escape doors on the top two floors are served by an external metal staircase; windows include 2-by-2, 3-by-3 and 3-by-5 panes and 8/12/8 sliding sashes, all timber-framed.

Toilet stack 4L1 is a five-storey structure in concrete serving all floors at the south end of the east elevation. Toilet stack 4L2 is a five-storey brick stack at the south-west corner with a flat concrete roof and a ventilation slit to each floor.

Buildings 4M and 4N are included in the companion listing record and are not described here.

Block 5 — Water Treatment Works

This later 20th century block comprises miscellaneous single-storey buildings at the south end of the site, most associated with a 1990s dye works. Water was conveyed along the original mill race from the Lagan, abstracted and chemically treated before use as process water in the dye house.

Buildings 5A and 5B cover a water reservoir at the head of the race from the river. Building 5A, at the north end, is of mid-20th century date with a felted bowstring truss roof and is described in the companion record. Building 5B is a later addition to the south gable of 5A with a pitched corrugated asbestos roof and concrete block walls; the only opening is at the south end where the water channel enters. Two galvanised metal footbridges — the Iron Lattice Bridge recorded separately — span the channel just south of 5B.

Building 5C has a flat concrete roof and brick and concrete block walls. A small concrete block pump house has been erected just beyond its south-west corner; there was no internal access.

Building 5D abuts the east face of 5C and covers a second water reservoir; it has a monopitched corrugated asbestos roof and concrete block walls with no openings.

Structure 5E, at the south end of 5D, is an open filter bed comprising a deep layer of fine sand enclosed by low brick walls.

Building 5F lies south of the filter bed with a pitched corrugated asbestos roof and rendered walls; its only opening is a door on the north gable. There was no internal access, but it probably houses water pumps.

Building 5G, at the south-west corner of the block, is a chemical store, entirely clad in corrugated asbestos with a shallow pitched roof. Three small concrete open water cisterns stand immediately to its north; chemical tanks to its north-west have been removed.

Block 6 — Gatehouse

This late 19th century building is included in the companion listing record. It is a former two-storey administration block set close to the main vehicular entrance on the northern side of the site, shown on the Ordnance Survey map of 1903. A bay to the eastern side and an addition to the south side have both been removed, leaving an approximately rectangular footprint. A canopy runs the full length of the north elevation, resting on a timber beam supported on cast-iron columns; between the columns are carved timber quarter-arches with drop finials at their meeting points, twelve such arches in all. The bases of the columns are fixed to squared sandstone coping blocks on a dwarf brick wall.

Block 7 — Offices and Laboratory

This two-storey later 19th century block is included in the companion listing record.

Block 8 — New Factory

This block originally comprised three long single-storey buildings erected in the late 20th century as part of a modernisation programme, aligned north-south along the west side of the site: a finishing department at the north end (8A) and a dye house in the middle. These buildings were largely dismantled in 2010 and relocated elsewhere.

Block 9 — New Making-Up Department

This block comprises a single-storey rubble stone building erected in 1887 (9A), a modern loading bay to the north (9A1), and a mid-20th century single-storey sawtooth-roofed shed to the south (9B).

Building 9A is aligned east-west at the north end of the block. Originally a four-storey flax store with a semicircular staircase at the east end and a brick goods hoist shaft on the north elevation, the building was recorded with an 1887 datestone at ground floor (since removed or obscured). Since a 1988 architectural survey, the building has been reduced to a single storey and the staircase and hoist shaft removed; it has been used for the temporary storage of goods awaiting dispatch. The building now has a flat bituminised concrete roof and walls of roughly-dressed random basalt; the east end is clad with profiled metal sheeting. Stepped brick quoins survive on the west gable, which still stands two storeys high. The openings are of segmental profile trimmed with brick, most now infilled or modified with flat concrete heads; surviving windows are 3-by-4 top-opening with flush concrete cills.

The north elevation is abutted by a modern loading bay constructed of a steel frame clad in profiled metal sheeting with a shallow monopitched roof, supported at the north side on concrete piers; roller shutter doors serve its north and west elevations.

Building 9B abuts the south and west sides of 9A, added in the mid-20th century and latterly used for making up, labelling and packing. The sawtooth roof, aligned east-west, has eight bays — two on the west gable and six along the south side of 9A; the apexes are linked by exposed steel girders. North pitches are glazed; south pitches are clad with profiled metal sheeting. A semi-basement runs along the east side with mass concrete walls; above, the east wall is of brick with yellow-brick quoins at both ends. The south and west elevations are of profiled fibre cement sheeting over a metal framework resting on a dwarf concrete wall. Window and door openings along the east side have concrete heads; a metal staircase at the south-east end provides external access.

Block 10 — Waxing Department

This block at the north end of the Island comprises two contiguous mid-20th century single-storey buildings aligned east-west (10A and 10B), with a later toilet block (10B1) abutting the north side of 10B.

Building 10A runs along the south end of the block, 11 bays long, with a pitched corrugated asbestos roof, brick walls and square-headed openings with concrete heads. Sliding timber doors serve the east and south elevations; the south and west elevations have metal-framed casement windows with concrete cills. Three circular vents run along the eaves.

Building 10B runs along the north side of 10A, canted at its north-west end, with a felted bowstring truss roof of 11 trusses and boxed eaves. There is no wall break with 10A, indicating that despite their different roof types the two buildings are contemporary. The east gable is of brick; the remaining walls have steel frames with felt shingles on vertical timber sheeting over wooden frames. There is a door in the east gable and assorted timber- and steel-framed windows to the external walls. Toilet block 10B1 abuts the west end of the north elevation; it has a felted monopitched roof, pebble-dashed walls and square-headed timber casement windows with concrete cills.

Block 11

This block consists of a long single-storey building aligned north-south (11A) and a smaller single-storey building spanning the river at right angles (11B). A building is shown on the site on the 1902 Ordnance Survey map, but the surviving materials appear to be of later date. A netting store is marked at the south end of the existing building on a 1954 plan; this may be the netting factory cited in the valuation records as having been built between 1929 and 1934. The river-spanning building is a mid-20th century infill between Buildings 3E and 11A.

Of Building 11A, little now remains except vestiges of brick walling at the north and south ends. A row of steel I-beams and remnants of concrete flooring indicate it was a double-pile building; surviving walls have assorted square- and segmental-headed openings, including a 2-by-3 top-opening window with a concrete cill at the south end of the west elevation. Open-sided cooling sheds, now demolished, formerly ran along the east side of this building.

Building 11B is a double-pile, single-storey building abutting the north-west end of 11A, spanning the river on reinforced-concrete beams; it is essentially an infill between Buildings 3E and 11A. It was gutted by fire in 2006 and is now in poor condition. The roof is of felted sheet metal over angle-iron trusses; the valley is carried on two steel I-beams supported at intervals by diagonally-braced composite steel uprights. The north and south walls are of corrugated asbestos over steel frames. The interior, accessible from both ends, was lit by 2-by-3 metal-framed windows along the side walls.

Block 12 is included in the companion listing record and is not described here.