Great Arthur House, London EC1

Great Arthur House is the centrepiece of the Golden Lane Estate, a seven-acre site composed of several mid-rise residential blocks arranged around landscaped courts. Great Arthur House is the largest block within the development. The estate also contains purpose built community leisure facilities and retail units along Goswell Road. It is one of the most influential British post-war housing estates and an important precursor to the Barbican Estate, also designed by Chamberlin, Powell & Bon.

At 15 storeys, it was the first building to break the 100ft height limit in the City of London and for a short time was the tallest inhabited building in the UK.

Influenced by the work of Le Corbusier, the design of the Estate was regarded from the outset as a model of social integration with early tenants including doctors, police officers, secretaries, cleaners and caretakers – with an emphasis on one bedroom flats for single people and couples.

John Robertson Architects undertook the recladding of Great Arthur House for the City of London Corporation, a Grade II listed landmark, part of the Golden Lane Estate designed by Chamberlin, Powell and Bon and completed in 1956. The new cladding replicates the delicate extruded profiles of the original 1950s façade, together with the distinctive use of yellow glass. The new façade improves the performance of the original windows with a double glazed and thermally insulated prefabricated panel system. The project involved extensive consultation with the City Planners, 20th Century Society and leaseholders and tenants. It received an RIBA National Award in 2019.

The original window system was a single glazed, aluminium framed assembly fixed to a teak sub-frame and made by Quicktho Ltd, who also manufactured Routemaster bus windows. After over 60 years of use, the original windows had reached the end of their serviceable life. JRA replicated the sliding windows with a more energy efficient counterpart as part of the new curtain wall replacement and incorporated a new system of trickle vents to improve comfort and ventilation.

During the development of the design of the new curtain wall the materials, including the distinctive sunshine yellow coloured glass, were replicated and upgraded to provide a high performance thermally efficient double glazed façade. The new curtain wall was designed as pre-fabricated panels and extensively tested by an independent laboratory in Germany to review its performance prior to manufacture. A mock up of the new panels was also installed on site.

The striking yellow colour is now clearly expressed and provides a welcome counterpoint to the lower blocks of flats and maisonettes at the Golden Lane Estate clad in contrasting primary hues. The existing concrete slab edges of the building were also strengthened with steel plates with integral fixings from which the new curtain wall is hung.

The replacement curtain wall has dealt with the legacy issues of water ingress and air leakage and has significantly improved the environmental performance of Great Arthur House by reduced air permeability and greater thermal efficiency, with a predicted 31% reduction in heat loss and a 13% reduction in C02 emissions.

The residents of the 120 flats at Great Arthur House were extensively consulted throughout the course of the work and were at the heart of the retrofit project. This took the form of stakeholder engagement via exhibitions, talks and drop in sessions to discuss the evolution of design proposals together with regular newsletters. All works were carried out with residents living in the building. This was immensely challenging and to make this possible, JRA devised a temporary structural insulated panel that was positioned inside the apartments while the recladding works took place. The new cladding system of storey height prefabricated panels eliminated the need for external scaffolding.

In addition to replacement of the curtain wall, JRA has restored the pergola and distinctive oversailing curved roof feature, which is cited as one of the first purely decorative motifs to appear on a modern building in London.