Rainscreen cladding made from polycarbonate panels and fibre cement boards on a performing arts building at Redbridge College by Ayre Chamberlain Gaunt

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Andy Matthews

Ayre Chamberlain Gaunt’s ‘Box Theatre’ is a performing arts building at Redbridge College’s Chadwell Heath campus in Romford, London. Conceived as atranslucent box elevated above black brick plinth, the two-storey scheme houses music recording studios, teaching spaces and a 264-seat performance space. The latter doubles as a multi-purpose hall with retractable seating allowing for enrolment days, exhibitions and other gatherings. Concealed shutters along the flank walls provide blackout for performances, while a series of double doors allow the audience to spill out into the adjacent courtyard, which fronts the college restaurant and cafe. The reception is located within a double-height foyer area to the front of the hall.

The BREEAM Excellent-rated project also provides a new public face for the college – the street frontage having previously been hidden behind and accessed between residential buildings. Landscaping in front of the scheme is in intended to connect the college grounds to the local context and extend the heath into the campus. An avenue of trees defines a pedestrian route with informal paths through raised grass banks. Grass mounds and external furniture create an informal theatre space for rehearsal and play.

Central to the scheme is a visually-striking rainscreen cladding system comprising 40mm thick, triple-cell polycarbonate sheets and fibre cement panels mechanically secret-fixed to a metal frame and vented at the top and bottom. Fibre cement panels dominate the rear of the building, helping to accentuate the use of polycarbonate at the entrance. Two shades of fibre cement panel (charcoal and anthracite) are combined with three colours of polycarbonate (green, yellow and clear) to create tonal variations along the facade. Different levels of translucency within the polycarbonate panels add further visual interest.

A particular challenge was achieving the diffused lettering/signage to the rear of the cladding, says the architect. Mock-ups were constructed to test the visibility of the lettering at different times of the day. The signage was cut from 3mm thick black pvc sheeting and fixed to a white calcium silicate board which forms the substrate to the metal cladding system at first-floor level. LED luminaires at the top and bottom of the polycarbonate panels illuminate the building at night, making the first floor appear to float over the ground.

The top of an adjacent, 15-metre-high redundant boiler chimney has also been clad with polycarbonate sheets (utilising the same colours as the theatre) to form a beacon for the college.

The building’s environmental strategy combines mechanical heat recovery ventilation with controlled and automated natural ventilation systems. The main performance space is naturally ventilated using roof-mounted windcatcher turrets incorporating photovoltaic-powered boost fans. Automatic dampers linked to air quality and air temperature sensors within the space allow for a large (and quick) changes in occupancy levels during performances. The turrets also facilitate secure night-time cooling in the summer.

Air intake for the foyer space is via a bank of louvres located below the raised polycarbonate box. The air-in path feeds through to the exhaust via passive roof turrets. These are interspersed with circular rooflights and lighting. On-site electricity and hot water are provided by a roof-mounted photovoltaic array and solar thermal panels.

Significant sound insulation measures were taken to minimise noise transmittance from the dance studio, control room and auditorium to surrounding residential area, says the architect. This included fitting acoustic attenuation and insulated motorised dampers to the ventilation turrets. Reverberation within the main auditorium is controlled using perforated plasterboard and slatted walnut battens interspersed with sound deadening material.

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