Ballyskeagh Bridge, Ballyskeagh Road, Lisburn, Co Antrim

This twin-span masonry arch bridge carries the Ballyskeagh Road high over the Lagan Navigation, here running in a rock-cut channel. One arch spans the water and the other the former towpath on the east bank, now a public footpath. The bridge is built of Triassic sandstone throughout. The abutments and pier are of dressed sandstone blocks, brought to courses and embellished with vee-jointed cut stone quoins. As the pier rises from the bank, there was no need for a cutwater on the pier. There are towrope marks on its quoins. Both arches have semicircular profiles; that over the water is taller and wider than that over the footpath. They have vee jointed cut sandstone voussoirs which are stepped into the spandrels and also raised keystones. The main span has three putlog holes at arch spring level. The soffit has been reinforced with concrete, cast in situ. There is also a tie bar holding its sides together at crown level. The soffit of the footpath arch has been gunited (previous survey notes indicate that it was brick). A string course runs around the abutments and pier at arch spring level. The spandrels are of squared rubble, with a string course over. The parapets are of random sandstone rubble, with some quarried basalt and Silurian shale admixture, all coped with concrete. However, sandstone coping blocks, possibly original, survive at the west end of the north parapet. The carriageway comprises two lanes, but no footpath. Pedestrian traffic is carried on a modern single-span metal girder footbridge just north of the road bridge. An electric cable is carried across the outside face of the north parapet. A steep flight of concrete steps runs up the SE side of the bridge. This is probably a modern rebuild of the steps which enabled the lock keeper (who lived in the lock house immediately SE of the bridge) to access a lock just north of the bridge. There is a twentieth century steel footbridge that spans the same distance adjacent on the North side.