5 Sloane Terrace (Cadogan Hall).

Cadogan Hall, situated on London’s prestigious Sloane Terrace, was the city’s first Christian Science Church, built in phases between 1904 and 1908. The wonderfully proportioned arches of the hall, its double-height windows and tiered gallery all remained, but the congregation had diminished and the structure was beginning to decay.

Location

London, UK

Client

Cadogan Estates

Architect

PDP London

Project Value

£7 million

Floor Area

5,900 m²

Status

completed 2004

Expertise

Structures

We collaborated with architects PDP London to spearhead a sympathetic conversion which saw the building’s function change from a magnificent place of worship to a rehearsal and concert venue for the Royal Philharmonic Orchestra.

The building’s external walls are faced with Portland Stone, and the roof comprises trussed steel topped with 38 mm planking and clad in copper. In terms of stability, the western side of the church comprised RC slabs supported on steel beams, in turn supported by load-bearing masonry walls. To the east, load-bearing walls were used in combination with slim cast-iron columns. Traditional corbelled brickwork bears onto a concrete mass foundation beneath basement level.

Our first step was to deepen the basement, installing a new reinforced concrete slab at a lower level. We removed two load-bearing walls and replacing these with steel goalpost frames. We were also able to minimise the risk of superstructure deflection and reduce cracking by installing one of these frames using a jacking system. We strengthened the lower ground floor slab using steel beams, and introduced RC stairs between these two lower levels.

Using the results of an initial structural survey which highlighted potential weak points, we implemented a programme of underpinning which included existing brickwork walls adjacent to existing lightwells and air ducts, and those close to the new lift pit in the north-east corner of the building. We also installed a new steel frame stage in the auditorium, with timber joists spanning between beams, bearing onto the supporting walls below.