Decorating Cumberland Terrace

Cumberland Terrace was designed by John Nash with the assistance of James Thomson and built between 1826 and 1828 by William Mountford Nurse as part of the final phase of the Regent's Park terrace development. The terrace was named in honour of the Duke of Cumberland, brother of King George IV, and was positioned on the eastern side of the park to face the site earmarked for the royal pleasure palace that Nash had envisaged as the centrepiece of his grand scheme. Although the palace was never constructed, Cumberland Terrace's extraordinarily elaborate facade was executed as designed, providing a permanent architectural backdrop of palatial grandeur. The terrace comprises 31 individual houses unified behind a facade of unprecedented richness, articulated by a central block surmounted by a vast triangular pediment containing a sculptural group representing Britannia attended by the Arts and Sciences, executed by the sculptor George Bubb. Flanking wings are linked to the central block by triumphal arches, creating a composition of dramatic spatial complexity. The terrace suffered significant damage during the Second World War, and a major reconstruction programme in the 1960s and 1970s, directed by Doris Brealey for the Crown Estate, renewed much of the interior structure while faithfully restoring the Nash facades. This reconstruction involved the recasting of numerous Roman cement ornamental elements from moulds taken from surviving originals, creating a facade that combines authentic early nineteenth-century fabric with mid-twentieth-century replica elements, a circumstance that complicates the conservation painting programme.

The conservation painting of Cumberland Terrace demands the highest level of technical expertise and project management, given the terrace's exceptional architectural elaboration and the mixture of original and replica fabric in its facades. A comprehensive pre-painting survey must be conducted, employing a combination of close visual inspection from scaffolding, percussion testing to identify areas of hollow or delaminated stucco, moisture mapping using capacitance and resistance meters, and petrographic sampling to distinguish original early nineteenth-century Roman cement from the mid-twentieth-century replica elements. This distinction is critical because the original Roman cement, produced from septaria nodules fired at relatively low temperatures, has a different porosity and chemical composition from the Portland cement-based replicas, and may require different repair and coating approaches. For all lime stucco surfaces, the finish specification is a potassium silicate mineral paint applied in two coats to achieve a chemically bonded, vapour-permeable finish. The critical technical challenge is achieving uniform colour and texture across areas of original stucco, repaired stucco, and replica Roman cement, which exhibit different absorption rates and surface textures. Thorough application of a silicate fixative pre-treatment, adjusted in dilution to equalise absorption across these different substrates, is essential for achieving a consistent finish. For the monumental sculptural group in the central pediment, conservation cleaning using laser ablation may be appropriate to remove embedded atmospheric soiling without mechanical damage to the delicate modelling. Any repairs to the sculpture must be carried out by a specialist conservator using a lime-based mortar sympathetic to the original Roman cement. Timber joinery, metalwork, and rainwater goods follow the standard Crown Estate conservation specification: linseed oil and alkyd systems for timber, zinc phosphate and gloss systems for iron, and patination oil for lead.