Cambus Iron Bridge, Cambus, Clackmannanshire

Andrew Millar describes the conservation of an early Scottish girder bridge.

The bridge as repainted but without timber decking,

The Cambus Iron Bridge is a Category A listed building and a Scheduled Ancient Monument. It is a rare example within Scotland of a single span prefabricated lattice girder construction, 68 feet in length. It was constructed in the early 19th century to span the River Devon and link with the distillery founded in 1806. The iron guide rails allowing a wheel gauge of four feet are still in evidence on the bridge, which was used by horse drawn wagons and pedestrians.

In March 1995, Clackmannan District Council refused a planning application by United Distillers which owns all the surrounding lands, to erect new security fencing which would have effectively impeded public access to the historic bridge. At a public meeting, over a 100 local residents of the village expressed their support for the Council's action. This prompted a debate about the future of the bridge. It had been closed the preceding year owing to concerns about public safety as it had lost much of its timber decking. Ownership of the structure itself was clarified as being in favour of the Council.

Accordingly, given the importance of the structure both in national and local terms, the District Council agreed in May 1995 to assemble a financial package to repair the structure and to reopen it to public use. By April 1996, the monies for the bridge had been assembled by myself involving major support from Historic Scotland and the first Heritage Lottery grant award in the County. This was greatly assisted by the decision to appoint a specialist design team headed by the Conservation Engineer Ted Ruddock, not only to reinforce the case for grant support, but most crucially, to ensure the correct conservation standards which has been a particularly vexed issue in relation to historic bridges. United Distillers, to its credit, removed nearby derelict structures from the riverbank.

The bridge as completed..

The client's brief and proposal was to repair the bridge in situ, fully respecting the historic and architectural integrity (based on principles of minimum intervention), consisting of masonry, timber decking (including reversible anti-skid surface), ironwork, painting, site interpretation and limited landscaping - sub-contracted to the Scottish wildlife Trust (to ensure the application of nature conservation principles). The opportunity was taken to investigate and return the bridge to its historic colours, namely Venetian Red and Brunswick Green which replaced the unassuming battleship grey. These paints were specially prepared for the site.

Through competitive tendering, the contract won by a local firm, Marshall Construction with the work being undertaken between June 1996 and March 1997. Extensive scaffolding to water level was required and the works had to be timed to certain months when the risk of flooding was less. In addition, as part of the CDM Regulations, there was protection of the water- course from both the preparation and finishing painterworks. The final total project cost was £57,485 well under budget of £76,000. Therefore within a period of two years from the planning refusal, the Council had assembled a financial package and intervened to repair the bridge to appropriate conservation standards.

The completed project will shortly become more accessible, as it forms part of the proposed National Cycle Network route, identified by Sustrans, and as such will be one of a series of historic structures linked by the cycleway. In my capacity as Project Manager to the Clackmannanshire Heritage Trust, it has been agreed that we progress an conservation audit of these structures in order to identify a rolling programme for intervention. As such the sustainable arguments for developing the cycleway will hopefully be complemented by sustainable objectives of reducing the rate of decay in these historic structures.

Andrew Millar, Sustainable Development Man- ager, Development Services, Clackmannanshire Council,

Context 58 June 1998