Chiswick House Gardens, Classic Bridge Restoration

Described as the birthplace of the English Landscape Movement, the William Kent designed Chiswick House Gardens have provided the inspiration for many other great gardens including New York's Central Park. In a £12m, two year project supported by the Heritage Lottery Fund this Grade I listed site has now been restored with key focal points in the landscape being returned to their mid-18th century appearance.  

Working with architects Dannatt Johnson, Gifford’s conservation engineers undertook a comprehensive programme of works to restore and repair the structures within the gardens. These included the 18th century Classic Bridge attributed to James Wyatt.  This elegant stone Grade I listed structure comprises a single Portland stone segmental arch spanning approximately 25m over a lake, with a steeply humped path over the top. It is decorated with Coade stone reliefs on both spandrels and has attractive stone balustrades.

Built for the 5th Duke of Devonshire as part of the extensive remodelling of Kent’s Palladian villa and gardens in 1774, the bridge was in poor condition after long exposure to the weather, pollution and lack of maintenance. Taking an approach of minimum intervention, the restoration team endeavoured to prevent further fabric decay, consolidating the integrity of the structure and revitalising its appearance to allow the original design concept to be appreciated.

The bridge was cleaned using mainly mechanical techniques, while very gentle abrasive cleaning was confined to areas around the more delicate or intricate surfaces.

There were many open joints with lime runs where pointing had been neglected and these were all repointed. Wherever possible, repairs to damaged stones were completed using mortar to minimise disturbance and maximise retention of the original material. Where replacement was essential, the new stones were carefully matched to original sizes, profiles and finish.

One special feature is the original paving, formed by channel stones diverting surface water to drain stones directly connected to the lake, which remained adjacent to the inner parapet.  As the stones were no longer draining effectively they were all repaired and rebedded where necessary, so that the original drainage system is now in good working order.

Gifford and Dannatt Johnson’s collaborative approach achieved a dramatic result, with the cleaned and repaired bridge regaining its place as a destination for visitors to the gardens.

• Structural and conservation engineering

• Historic Bridges and Infrastructure Awards 2010; commendation
• Landscape Institute Awards 2010 – Heritage and Conservation category; highly commended

Related project - Chiswick House Cafe