Radio station's conversion to school brings better light transmission

Established in 1926, Rugby Radio Station, just east of Rugby was, in its 1950s heyday, not only the communications centre of the UK but the largest radio transmitting station in the world. The very low frequency transmitter station and its power hall lay at the centre of a huge, flat site, surrounded by 57 aerials, 12 of which were 250m high, guyed steel-frame masts. Part of the Imperial Wireless Chain, these sent telegraph messages to the Commonwealth, and later, during the Cold War, were the sole means of communicating with the Polaris submarine fleet. Decommissioned in 2003, most of the masts were gone by the time it was grade II listed in 2005, which did nothing to prevent the loss of the last four or arrest the buildings’ decline.

Until 2015 that is, when strategic developer Urban & Civic – having bought a swathe of nearly 500ha of land, including the station site, to create a new residential quarter for Rugby – approached van Heyningen and Haward for help to convert the derelict site into a 1200-pupil secondary school, part of the social centre of its new suburb of Houlton. vHH partner James McCosh recalls the power hall’s massive DC motors feeding 50,000 volts across to the transmitter hall’s huge glass amplifier valves and octagonal copper ‘tuning coil’ – cooled by a water tower that is now the centre of the school campus. That it would be a campus was a given, says McCosh, as the spaces’ proportions  – one was 40m by 12m by 12m – made it wholly unsuitable for conventional classrooms. 

 

Looking at both halls and the later ad hoc infill between and alongside them, the firm knew that to realise a working school, it needed to have meaningful discussions with specialists about which buildings should stay and which should go. The early involvement of Historic England was key. ‘It was grade II listed but Rugby Council didn’t have a conservation officer, so we approached HE as we felt it would give Rugby the intellectual backup to be braver than it otherwise might have been,’ says McCosh. It also helped with calming the nerves of the DfE, which had given vHH its standard output spec and budget to work on a listed, industrial building – ‘the kind of thing they’d usually run a mile from. They just wanted nice straightforward buildings at lowest cost; a lot of our work was convincing them that it could be done.’

Despite the constraints implicit in working with such a complex brief, vHH has done it, creating a school that generates critical mass at the centre of a large site. Constructive discussions with HE resulted in the clearing of later accretions between the power and transmitter halls, leaving only their outer walls. Now facing south to the future neighbourhood square, its open brick arches give students access to the north of the site past the water tower, to where vHH has built two science and humanities blocks of classrooms and labs. In the transmitter hall are art, drama, music rooms and top floor sixth form area, with central loos, support, and lifts. Bookending it all are two red-painted steel stairs offering pupils a visceral sense of the building’s original scale. The power hall, stripped of generators, has been transformed into assembly hall, refectory, kitchen and general education spaces. To the west, a new sports hall serves needs of both school and community.

Interestingly, the old buildings had a direct influence on window specification, not only in their new iteration, but on the new blocks too. Given their listed status, vHH knew thermal compromises were going to be made in both halls, so the new blocks’ performance would have to be good enough to offset that. But specification was also dictated by the nature of  the buildings. McCosh explains that the transmitter hall windows were all timber-framed, with a form of Bakelite bolts used throughout to prevent the possibility of arcing from the equipment. The power hall, meanwhile, a steel-framed structure, had steel windows. As far as possible, vHH worked with this logic, making the interventions readable – as it did in the ‘corrugated’ brick of the new stair access blocks on the transmitter hall’s west side.  

In both halls, the strategy of window replacement ran alongside considered thermal upgrade of the fabric. With the transmitter hall’s Edwardian, arched, timber single-glazed fixed light windows deep-set into the solid brick skin, secondary glazing was considered, but McCosh says the feeling was that it would visually impinge on the view of original windows. The decision to use double glazed replicas was, he says, set by Historic England’s wish that the building have no visible plant, as reducing the cooling load demand on the MVHR to keep kit compact meant openable lights were a prerequisite to provide free cooling. Installing the new windows meant interfacing with the firm’s insulation strategy for the solid brick walls, developed with consultant Etude; a fully ‘moisture open’ layering of lime parge coat, wood fibre insulation and Fermacell. New first floor windows inserted into the west wall and picture windows in north and south walls were set in line with the brick face. Wall insulation overall could have been thicker, McCosh notes, but they were mindful that differences in thickness at reveals could result in condensation, and that to avoid it, consistency of insulation was a priority. At north and south sides, the thermal boundary is behind the new steel staircase walls’ inner face; the void they sit in residually heated to 16C, the original brick able to be read beyond a simple lime wash.

The power hall’s Crittall arched steel windows were replaced by an AluProf aluminium system, as vHH found that, as elsewhere, thermally broken steel frames were too expensive. While they did find an aluminium frame that replicated the original’s outer mouldings, it too was not thermally broken and needed a large transom to stiffen it. vHH compromised by adding an extra aluminium flat on the frame to provide some sectional relief to the system. In new computer spaces above the kitchen, original stippled glazing was copied, resulting in a ‘lovely’ quality of light in these spaces.

With the walls stripped back to reveal the original glazed brick faces, new ground floor openings in the refectory’s west wall were filled with a proprietary SAS triple-glazed grey-painted sliding door system, capable of being locked open to allow al fresco lunching on the new paved terrace. On the roof meanwhile, the original rooflight openings proved a good means of ensuring free cooling in the summer through clerestory venting. vHH had hoped to use a self-supporting rooflight, but due to the opening size, it introduced a 100mm by 50mm welded RHS stiffening frame around to support the actuated Roofglaze system specified. The space packs a punch, light pours into the industrial-scaled refectory volume, and with elements of the original electrical kit still installed, the place has a special, one-off feel.

McCosh says of the new Humanities and Science block design that its north-south orientation helped with energy efficiency and made for a glare-free teaching environment. The flat north elevations, where windows are flush with the brick facades, are contrasted on the south with a deep facade that shades the glass. McCosh points out that the brick fins doing this are not structural and are tied back to a long, thick, insulated brick skin, ensuring wall/window interfaces are kept simple as possible. DuPlus-installed large SAS PURe triple-glazed fixed lights to classrooms have hinged opening vent panels on each side for summer cooling. Blocks were specified to be as airtight as possible, resulting in only two small MVHR units on each. ‘Energy use intensity here is 67kWh/m²/yr and the LETI guide for zero carbon schools is 65, so it’s high performance,’ says McCosh, adding: ‘Windows are designated air permeability Class 4 – about as good as it gets.’ 

But it was also about aesthetics. Keen to complement the industrial buildings’ industrial nature, vHH settled on a German clinker brick, whose more highly-fired versions have a slight sheen, particularly in the south light. With the specified stainless steel lintels, the contractor offered shiny versions but the architect chose ones that dull over time. And in the facade’s depth, the practice ran a concrete bench so kids can sit and appreciate the water tower gazebo that acts as the fulcrum for the campus.

For now this lies empty, needing £500,000 more than they had to insert a room behind its Diocletian window. I hope they raise it; for ­despite having only one form, there’s a potentiality to this school. On a DfE budget, vHH has not only returned a disused building to good use and made it perform to the regs demanded of a newbuild, it has also generated a palpable sense of place in the process. In 2026, when the first cohort enters sixth form, Houlton will be marking a centenary; and it too, like the ­famous ­private school in town, will be hardwired into a legacy.