The Greenhill Building – ADC

Chris Dyson Architects has completed its competition-winning design for a new teaching and events building on Harrow Arts Centre’s London campus. The new Greenhill Building replaces a temporary Portacabin that had reached the end of its life. It sits to the rear of the grand Grade-II listed Elliott Hall, a Gothic building that houses a large theatre and was completed in 1904, and next to the former boiler house, with its distinctive chimney. A cluster of brick single-storey buildings – now artist studios – were historically part of the Commercial Travellers’ School and its farm, and once surrounded by fields.

The project is an early example of a fully cross-laminated timber (CLT) arts centre, proposed by the design team as an affordable, low waste and low carbon alternative to structural steel. The corrugated fibre cement cladding is typically used for barn roofs. The profile, selected from a farming brochure, is generally specified for livestock and equestrian facilities. A pragmatic choice, it offers good thermal performance and protects from heat and moisture.

Lightweight and fabricated off site, the system reduced the need for expensive foundations and meant that the entire main build was completed in under nine months. All materials were selected with consideration of their future use – just as CLT can be dismantled and repurposed, the cement fibre cladding panels can be ground down to create new ones. The building itself is designed to be similarly adaptable and can be easily modified for a change of use.

The architects conceived of a solution that could provide the spaces for yoga classes, art clubs and celebrations that the local community had asked for during public consultations, while also supporting HAC’s aim to be more financially sustainable. Inspiration came from the site’s legacy of agricultural buildings, which informed the L-shaped plan around a ‘yard’ and the red corrugated façade, made from a fibre cement more typically found on farms.

On plan, the simple two-storey building maximises useable space. The two large teaching rooms on the ground floor have double doors opening onto a courtyard, creating alternative access to allow events in each space simultaneously – a shaded terrace for weddings and space for classes to spill outside. Above this are two further top-lit teaching rooms beneath the roof, and a small studio with a view of trees. A serrated roof peeks above the surrounding brick buildings to signal something is new. Each asymmetrical pitch takes advantage of north light and incorporates glazing to create bright, top-lit rooms; to the south, the roof will have solar photovoltaic panels to generate power for the electric heating.

The budget was focused on the elements that would most impact everyday use, such as providing acoustic insultation between floors – “a dance class upstairs won’t disrupt the concentration of a life drawing session downstairs,” as Mathew Witts, the lead architect on the project explains. There are still a few flourishes, such as a generous picture window illuminating the timber stairs, which wrap around a central lift. Internally, the warm grain of the CLT is exposed; decoration comes through the subtle patterns of light and shade cast through the building’s partially glazed roof.

Mathew Witts, a partner at Chris Dyson Architects explains: “Part of the construction challenge was to manage our budget against rising material costs and availability during the pandemic. This was achieved through pragmatic material choices, close collaboration with suppliers, clear priorities and keeping our focus on the building’s eventual users. Heating and ventilation within teaching rooms are all manually controlled, and lighting is controlled by movement sensors, so as not to waste energy. For services, our design uses off-the-shelf commercial cable trays to minimise installation costs and save time.”

As well as enhancing the connections between the buildings – an objective of the existing HAC masterplan – the project also addressed the long-standing issue of flooding on the campus, caused by a natural stream running through the east of the site. A new swale – a vegetated pond – now channels excess water to an underground tank. Seeds have been sown to develop some of the green spaces around the building; this is part of a further phase in a long-term rewilding plan by HAC to develop new landscaping across the site.

Chris Dyson, founder and principal of Chris Dyson Architects, said “The architecture is unashamedly new, but we were sensitive to HAC’s heritage, the site’s history and patchwork of buildings. We embraced the challenge of doing more with less, creating more useful space for people, but using less material, less energy, and pushing for a full CLT structure. Some visitors have said the serrated roof reminds them of a factory, which seems appropriate for Harrow’s creative engine – this campus is such a hub for arts and cultural industry in the area, we’re delighted to have played a part in helping to secure its future.”