Durham’s iconic Old Elvet Bridge in the heart of the town centre underwent preservation work back in 2017 to safeguard the future of the bridge. Now just over two years on since the work has finished, the bridge is holding strong, and Durham council are happy with how the work went.
The bridge’s life began back in the 12th Century however it was widened in 1805 to almost double its original size to 9.5 meters. There was, however, issues with the bridge’s arches, and an inspection in 2017 identified that the arch barrels were saturated in some specific areas and water staining to most of the arches. This staining indicated that any waterproofing left on the bridge was inadequate.
Durham County Council (DCC) who are responsible for maintaining the bridge understood the need to replace this waterproofing as a failure to do so would have resulted in further damage to the masonry.
A number of solutions were put forward to Historic England however they were deemed unsuitable for several reasons. In the end, DCC worked with Historic England to find a solution.
Mark Readman, highways services manager at Durham County Council, said because the Old Elvet Bridge is a Grade 1 listed structure, “we worked in partnership with Historic England to choose a product to which they consented to.”
The solution was CC HydroTM (CCH), a Geosynthetic Cementitious Composite Barrier (GCCB) with a hydrocarbon resistant geomembrane attached to a PVC backing. This added geomembrane, along with the concrete filled geotextile allows the product to be installed in a totally different way to traditional concretes. Concrete Canvas Ltd products have been described as ‘concrete on a roll’ as it arrives on site in bulk or batched rolls and can be cut to size with basic hand tools. As a result, CC is incredibly quick to install and requires far less disruption to the local environment than poured concrete. CC is also used for slope protection and lagoon lining, while the company also produce inflatable semi-permanent shelters.
Due to CCH being used, the product was thermally welded to secure the joints between strips of the product. Following this, the CCH is hydrated to activate the concrete mix and begin the setting process. CC and CCH products reach 80% strength within 24 hours and full strength within 48 hours. Once the CCH had hardened, the flag stones were re-laid on top of the CCH layer, and the bridge was reopened to the public with minimal disruption having been caused.
Now two years on since the work was completed the bridge remains a key attraction in Durham town centre. Mark Readman also said: “the product (CC Hydro) was cost effective and easy to install, and since the works were completed, we have had no further problems.”