Tim Ronalds Architects’ experimental ‘Hall of Science’ at Sevenoaks School

Buildings.

Words
Ian Latham

Photos
Helene Binet

The Science and Technology Centre and Global Study Centre are the latest manifestations in Tim Ronalds Architects’ deft masterplan for Sevenoaks School in Kent. The two buildings form an L-shaped block that, with the neighbouring Performing Arts Centre of 2010, defines a generous landscaped square, a new centre of gravity within the hitherto incrementally developed campus. Formerly a car park and drop-off point somewhat disconnected from the school’s network of pathways, ‘The Flat’ was bordered by nondescript buildings that devalued the distinction and effectiveness of the school’s more historic buildings and paid scant respect to the beauty of the adjacent 1000-acre Knole Park. Now that’s all changed.

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Both the Science and Technology Centre (STC) and the Global Study Centre (GSC, mostly sixth-form social and study spaces) are entered beneath cantilevered steel canopies, powder-coated bright yellow to chime with the fizzy-coloured window units, which suggest entrance and cloister as much as they provide shelter. The canopies echo those attached to the Performing Arts Centre (where they are crafted in steel and timber, like the auditorium within), and resonate with the architect’s earlier work, a signature rather than superfluous house style. These subtle signifiers acknowledge that most of those entering the building will have done so before, so there’s no need for a look-at-me entrance – an approach that permeates throughout this finely judged project.

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The GSC and STC read as separate buildings (as they were originally envisaged), but they connect internally, with the former shorter block rising three storeys to face The Flat, and the latter tucking its lower third level into the sloping site. The formal relationship is finely nuanced, with the sixth-form building prominent and the science block transitioning to the representational gable of the Performing Arts Centre. Oversailing both arms of the ‘L’ is an array of north-facing factory rooflights (also optimising a photovoltaic installation), the consequence of which gives the shorter block a horizontal parapet and double-pitched roof, while the longer elevation profiles its saw-tooth gables. The fenestration also differs, with the Global Study Centre’s regular grid suggesting a static vertical arrangement in contrast to the more dynamic linear sets of windows and ventilation cassettes of the science building.

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On entering the STC at mid-level, you step immediately into the capacious, full-height hall around which everything is apparent – the interior’s unexpected generosity of scale is an aspect it shares with other projects by the architect. Above is the north-light roof, its soffits precisely precast in concrete, and below is the narrower lower-ground level, with all levels connected by a pair of elegant hung and cantilevered steel stairs which link with delicate balcony balustrades.

Wrapping around the animated hall are ranks of laboratories and classrooms, where more studious activities are seen through glass walls and display vitrines. The proportions of the hall’s platforms and racetrack galleries enhance their utility, truly evoking the ‘Hall of Science’ that was an aspiration in the competition presentation. This space has a robust, experimental character that accommodates daily ebb and flow with ease, and this is brought into calm focus by a pervasive, ethereal atmosphere, the result of careful manipulation of light and sound through multiple daylight sources and acoustic absorption.

The array of rooflights floods the hall with soft north light while side light filters from the external windows to east and west, tempered and reflected by the periphery of glass-walled laboratories. The placement of windows, together with its loosely relaxed arrangement, defies the internalising effect of the atrium type. Entering the heavy masonry structure with an expectation of darkness to find this vast, light-flooded hall is truly uplifting.

The ‘Hall of Science’. The precast concrete and steel roof structure, designed with Eckersley O’Callaghan Engineers, spans the atrium and laboratories. The precast was detailed to achieve a slender appearance while maintaining the concrete aesthetic, integrating services and providing thermal mass to the upper floor. Steelwork framing lifts the precast panels into the north-facing skylights. The imposing mass of exposed concrete is offset by elegantly detailed features, including glazed steel canopies, glass display vitrines and light steel-framed balustrades. The two cantilevered steel atrium stairs were fabricated offsite and lifted into position fully-formed through the partially completed roof structure.

Engineered with Max Fordham, the spaces are well daylit – the sawtooth roof and open atria deliver glare‐free yet characterful north light. The envelope’s glazing balances winter-time heat loss and summer-time solar loads with daylight. The thermally massive structure is naturally ventilated to provide comfort all year without compromising the acoustics or the blackout potential. Fresh air is drawn directly into the laboratories, passing out through acoustically attenuated air paths to the atrium where it rises to the extract rooflights. The facade is designed to admit controllable air volumes with blinds fully lowered, whatever the weather. During winter the BMS maintains ideal air quality without overcooling or draughts. During warm weather the structure is automatically cooled at night. The few spaces prone to overheating have borehole water circulating through concrete soffits. The water is then reused for toilet flushing.

At present, the floors are arranged with biology on the middle entrance level (facilitating outside study), together with physics, which also shares the upper floor with fume-producing chemistry laboratories. Technology is on the lower ground level (at grade on the back due to the site slope), together with a divisible full-length multi-purpose room, nestled against The Flat with clerestorey windows. This latter space can be configured (and separately accessed) for a wide range of activities, aided by a terrace of retractable seating, but as the only conditioned space in the building, it will be deployed for the school’s serious business of exam-sitting.

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Particular care was invested in the laboratories, from their flexible desking arrangements to the integration of ventilation cabinets with windows and multiple blind systems. Throughout, the functional diagram is implemented with an apparent ease that belies the effort in reaching that outcome. But this building is more visceral than technological, with a richness of detail where it matters most, from the handrails with their slender balustrades to the precision of the precast concrete, and the clever multi-functioning window units.

The architect has made everything work hard as material finishes are exposed in a legible, expressive structure that eschews any notion of gimmick, fashion or deceit. In a recent lecture at the Barbican Centre, 2014 Royal Gold Medallists Sheila O’Donnell and John Tuomey described their work as “elaborated ordinariness”, a characteristically self-effacing statement that understates its strength perhaps, but it’s territory they share with Tim Ronalds. At Sevenoaks, the elaboration has been achieved by impressive, almost familial teamwork, both within the office and with the consultants, the contractor and the client team led by head, Katy Ricks. Sevenoaks’ nurturing building puts many university science departments to shame, and anyone concerned for the future of the discipline should take note of this inspirational exemplar.

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