Where the Old Bridge runs over land in Strood, a series of arches are built into the brickwork. These arches house a number of Trust workshops and stores, and passers-by will be aware the brick wall surrounding them is in a rather poor state.
There is open cracking and distortion, including places where the brickwork is no longer in line.
First of all, let us reassure you this wall is a non-structural façade. It was built some time after the main structure of the bridge, is of a half-brick thickness and conceals the supporting wall. While this is good news from a safety point of view, it in no way lessens the need to fix some very unsightly cracks on a Grade II listed bridge.
Some attempts at cosmetic repairs have been made in the past but as these have been unsuccessful in the long-term, it was decided to take the time to monitor and investigate the damage over a number of years.
In short, the damage is believed to have been caused by movement not long after the wall was built. Some movement can occur naturally during the first few years in place, when moisture is absorbed. A lack of expansion joints and brick ties linking the two walls would also have had an effect. Add to this temperature changes between the core of the structure and the façade and the cracking was probably to be expected.
Studies to test this have included the installation of glass ‘tell-tales’ across the cracks, regular inspections and the examination of historical records from the Trust’s archives.
Now a reasonable amount of information has been gathered, the challenge is to fix all the cracking and displacement in a way that will last.
You will be able to read about the repair options we came up with in the next entry.