Spencer's Bridge

The Department's description

Exterior description and setting

A triple-span masonry arch bridge which carries a secondary road between Moira and Hillsborough over the floodplain of the River Lagan.
The bridge is of random rubble construction throughout except for its cutwaters and arch voussoirs. The former are of triangular profile and step up at both ends of the piers to just above arch spring level. They are of dressed sandstone blocks laid to regular courses and continue up to the tops of the parapets in the form of shallow rectangular basalt rubble pilasters. The arches are of equal size and of three-centred (‘semi-elliptical’) profile. Their voussoirs are of vee-jointed cut sandstone, with slightly projecting keystones. Their soffits have been rendered with cement, but random rubble is visible in places. Tie rods (two per arch) hold the sides of the bridge together. The downstream (N) elevation is identical to the upstream (S) one except that a lagged water pipe runs across above crown level. It sits on an RSJ which is supported on crude mass concrete columns rising from the sandstone cutwaters.
The carriageway has a slight hump and carries two lanes. The parapets have drainage slits at road level and are coped with chunky undressed stones. Inserted into the road face of the upstream parapet, directly over the crown of the middle arch, is a finely dressed granite post (square cross-section and rounded top) carrying the inscription ‘1843’. Set into the stone, immediately above this date, is a small cast-iron plaque bearing a coronet and the letter ‘D’ (denoting Downshire, the principal land owning family in the area).
The upstream faces of the long approach roads, walled to each side with random rubble masonry, have been strengthened at their bridge ends with random rubble buttresses; that on the east approach is relatively recent. A small segmental-headed flood arch with cut sandstone voussoirs is visible on the eastern approach. A similarly sized flood arch is also visible on the north side of the western approach (it is blocked or obscured by vegetation on the upstream side). However, it has split stone voussoirs and appears to be of earlier date. According to the Ordnance Survey Memoir (see historical), there were five flood arches in total. The three which were not observed during this survey probably exist but have been buried or hidden by vegetation

Historical information

This bridge is named after the Spencer family, landowners in the Trummery district (a mile south of the bridge). Although cited as Inisloughan Bridge on Oliver Sloane's 1739 map of Co Down, Walter Harris' 1744 map and Taylor & Skinner’s 1777 map both cite its as Spemcer's BRidge, and this name persists on subsequent OS maps fom 1834 onwards.
The 1837 Ordnance Survey Memoir for Magheramesk Parish describes it thus: “Spincer’s Bridge [sic] across the Lagan river, on the leading road from Hillsborough to Moira … has three half-circle arches: span of centre arch 22ft, span of each of the outside arches 21ft; average breadth of the road on the bridge 21ft 6in, average height of parapets 4ft, thickness of parapets 1ft 6in, length of parapets on either side of the road 355 yards, length of bridge 30 yards. Detached from the bridge on the county Down side stands three arches to accommodate in case of high floods in the river. These arches stand at some distance one from another. The span of the west arch of this is 12ft, span of each of the other two is 7ft.
On the county Antrim side of the bridge also stands two arches to serve as above, span of each 10ft. These small arches are turned, or rather faced, with rough quarry stones and the large or bridge arches faced with cut freestone. The remainder of the work, including the parapets, is built of quarry and land stones. The main bridge seems in a permanent state of repair. The other arches and the parapets have suffered partial dilapidation.
The bridge is said to be old, but no accurate account here of the cost, date of building or who the engineer as of it. It is said to be erected at the expense of the two counties, in which it is equally situate.”
Both the 1834 and 1858 OS maps show three cutwaters, thus indicating a four-span bridge. This depiction is clearly inaccurate given the 1837 OSM description and presence of the 1843 stone above the middle arch.
The precise date of this bridge is uncertain. The fine quality of its arch voussoirs would accord with an early/mid19th century construction date. As arches of this quaity are actually described in the OSM (“faced with cut freestone”), either they were either rebuilt in 1843, or that the date on the stone over the middle arch is when the post was positioned here, possibly as boundary marker of that date (rather than a record of the bridge’s reconstruction). The crude floodarch in the western approach would not be amiss in an 18th century context. One can only conclude therefor that a causeway over the river has existed here since at least the mid 18th century but the actual bridge was probably rebuilt at least once during the first half of the 19th century.

References - Primary sources:
1. Sloane, O. Map of County Down (1739).
2. Harris, W. Map of County Down (1744).
3. Taylor, G. & Skinner, A. Maps of the Roads of Ireland, p.282 (1777).
4. PRONI OS/6/3/13/1. First edition OS six-inch map, Co Down sheet 13 (1834).
5. Ordnance Survey Memoir, Co Down: Magheramesk Parish (1837). Reprinted as Day, A. & McWilliams, P. (eds), Ordnance Survey Memoirs of Ireland, vol.21, p.118 (Belfast: Institute of Irish Studies, 1993).
6. PRONI OS/6/3/13/2. Second edition OS six-inch map, Co Down sheet 13 (1858).

References - Secondary sources
1. Brett, C.E.B. Buildings of North County Down, p.251 (Belfast: Ulster Architectural Heritage Society, 2002).

Criteria for listing: architectural interest

A. Style
B. Proportion
C. Ornamentation
D. Plan Form
F. Structural System
H-. Alterations detracting from building
J. Setting

Criteria for listing: historic interest

X. Local Interest
V. Authorship

Evaluation

A triple-span masonry arch bridge, which carries a secondary road between Moira and Hillsborough. Although it is probable that a causeway has existed here since at least the mid 18th century, the actual bridge was probably rebuilt at least once during the first half of the 19th century. This is a good example of a causeway bridge across the Lagan’s wide floodplain and forms an impressive landscape feature when viewed from afar. Although its character is marred somewhat by the crudeness with which the water pipe is carried across it, its architectural interest is retained by the quality of the arches and their constrast with the remaining rubble stonework. Its association with the Downshire Estate, also enhances its local historical merit.