Guildhall London Crypts, London, UK

The Grade II crypts are the largest medieval crypts in London, with the remains of an ancient roman amphitheatre located below the floor.

Built in 1042, the East Crypt is considered to be one of the earliest and finest examples of its kind. The West Crypt was built in the 12th century. Following the Great Fire of London (1666) it collapsed and was sealed; reopening in 1973 following extensive restoration.

The previous lighting installation, dating back to 1973, consisted of three main elements: column mounted tungsten wall sconces, T12 fluorescent lamps backlighting stained glass windows and tungsten halogen window reveal lighting.

dpa’s brief was to enhance the historic architecture whilst improving functional lighting for the crypt’s main use as an events venue. Although in most cases event organisers provide effects lighting equipment, it was essential to create a pleasant, comfortable backdrop and lit environment.

dpa worked closely with English Heritage and the client creating a lighting scheme to meet the brief and blend in with the architecture. The new installation reused existing mounting locations and cabling; wherever additional lighting elements were added these could not be permanently fixed, thereby avoiding damaging the building fabric.

Efficient, predominately LED, light sources were used, reducing energy consumption and ensuring a long lasting visually consistent installation.

The column mounted wall sconces were replaced with bespoke luminaires utilising unlensed LEDs, uplighting the vaulted ceiling, and a single medium beam LED downlight accentuating the column. Two luminaires were designed to suit the differing mounting conditions. The West Crypt used fixed focus luminaires whilst, due to uneven mounting conditions, the East Crypt luminaires were fully adjustable ensuring a consistent lit effect was achieved.

The luminaires backlighting the stained glass windows were replaced by more efficient T5 fluorescent luminaires on local dimmers, allowing the brightness to be adjusted to suit each location.

The window reveal uplights were replaced with bespoke free-standing LED wall grazer luminaires, accentuating the wall finishes and framing the stained glass windows.

Other existing lighting elements, over the entrance stairs and backlighting stained glass windows from open light wells, were upgraded with more efficient LED and Metal Halide

dpa identified further architectural elements to be enhanced; to accentuate the doors linking the crypts, bespoke surface mounted uplights were introduced. The development of which proved difficult as all lighting equipment needed to be concealed within the luminaire, whilst providing adjustability to suit the steps’ varying dimensions. At the East Crypt’s east entrance, miniature LED uplights were surface fixed via non-abrasive bonding and a spring clip.

The final result represents a robust lighting installation which is sympathetic to the architecture whilst creating a pleasant and comfortable lit environment.

Client: City of London Corporation
Heritage Consultant: English Heritage
Photography: Tommaso Gimigliano