NICK COX ARCHITECTS

Kedleston Hall - Marble Hall Rooflights

Location: Kedleston Hall, Near Derby

Building period: late eighteenth century

Listing Status: Grade I

Construction Value: c £150K

Articles: Written up for the Georgian Group magazine

The overall design for the house draws on the ideas of Palladio. The Marble Hall expresses the grandeur of the house and the inspiration taken from ancient Roman The ceiling springs from a highly embellished entablature above the corninthian columns and is divided into compartments. The central three compartments frame oval rooflights.

The rooflights have a long standing history of being problematic in terms of their ability to keep rain out and have been the subject of a programme of repairs that Nick Cox Architects were commissioned to carry out

The Project

The rooflights over the Marble Hall have been a challenge over the years and previous condition reports make reference to dripping skylights having been a problem for much for the 20th century.

Armed with an understanding of the historic design, informed by archive research, for the rooflights and roof structure, a programme of works was drawn up that involved erecting a temporary roof over the Marble Hall so the rooflights could be worked on. At the same time the opportunity was taken to work on the surrounding lead work and slates and to improve the stiffness of the roof structure, cracks in the downstand beams of the ceiling were of concern. The Marble Hall received floor protection prior to bringing in and erecting a lightweight ‘birdcage’ scaffolding. A temporary roof was erected over the works area. 

The three rooflights are of cast bronze. The actual rooflights themselves were found to be in good condition however, one of the shortcomings of the design appeared to be that the glazing bars were too short and so the glass did not extend enough to protect the seating of the rooflights. A detail was developed, in discussion with the metal worker, and trial mock ups to attach extensions to the glazing bars were carried out. The extensions were achieved without the need to cut into or work away any of the existing rooflight; The glazing bar extensions were cast in bronze to be in sympathy with the existing roof lights. 

The roof structure

The exposed roof structure, was surveyed as part of the works and an archaeological record was made of the carpenter’s marks.

Completion

The finished rooflights, with their extensions, were re-glazed with laminated glass to which an internal UV filter was added The approach adopted to the project enabled retention of all of the historic fabric of the rooflights and supporting structures but also allowed for improvements to be made to secure their long term performance.

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