Harris Academy

UK’s first Passivhaus secondary school delivers light and airy learning space

About this project

The Harris Academy Sutton is the UK’s first Passivhaus secondary school and the largest Passivhaus school in the UK.

Designed by Architype, the structure is formed predominantly from cross-laminated-timber (CLT), together with glulam beams, with only the partially submerged ground floor constructed from concrete.

The school is located at the centre of the new London Cancer Hub (LCH), a world-class research and treatment facility formed in collaboration between Sutton Council and The Institute of Cancer Research. With a special focus on the science disciplines, the school will benefit from its links with the LCH community to collaborate with employment partners and inspire the next generation of scientists.

A thoughtful design with community at its heart

Sutton Council has a strong sustainability ethos encompassed within its 'One Planet Living' strategy and low-carbon targets. As such the Passivhaus approach was well received, delivering exemplary sustainability credentials at a time when councils across the country are moving towards net zero.

Accommodating up to 1,275 students aged 11-18, the school's facilities such as the sports hall will also be available for local residents to use after hours, contributing to the healthy living values of the wider site. Moreover, the design was carefully considered with extensive public and local authority consultation to improve the local infrastructure, encouraging staff, pupils and parents to take sustainable routes to school.

Biophilia and designing for wellbeing

Nature is at the heart of the materiality: all classroom spaces have exposed ceilings, with acoustic rafts below, and corridors feature exposed CLT. The CLT roofs reflect the natural harmony of the building, with non-toxic materials providing exemplary air quality and environmental credentials.

Architype’s research into biophilia provided anecdotal evidence that the non-toxic, familiar materials help to produce a calming and non-stressful learning environment.

The classrooms are light and inspiring with optimised spatial orientation, the result of extensive daylight, noise, transport and ecology surveys. Meanwhile the interior of the sports hall is finished with exposed timber.

Where timber wasn’t used, Architype opted for a palette of similarly natural materials, including copper cladding on the sports hall exterior to reference the science-focused nature of the site. Copper was also used as a visual separation for the areas of the building which are multi-use, serving the public as well as students.

Designed to offer a university-style 'campus feel', the site includes outside terraced seating and social courtyards, adding to the knowledge sharing environment.

Historical trees were preserved and incorporated as part of the ecology-focused landscaping plan, providing the benefit of harnessing a mature feel for the new school, contributing to the improved horticulture of the site and creating a buffer between the building and its residential neighbours.

Use of timber

The floor slabs were designed to bear only on the external walls, glulam structure and central spine CLT walls, made possible by large continuous CLT panels. This means that the school’s internal layout is flexible, with the option for internal walls to be added or taken away as requirements change over time.

The building was designed with the circular economy and re-use in mind; the bolted connections to the glulam frame allow it to be dismantled and reused at the end of its life. Meanwhile, exposed soffits show the timber, helping the design language to be easily understood.

Moreover, the exposed timber structure makes the building more lightweight, assisting in reducing the need for piled foundations which significantly reduced the embodied carbon of the building.

Passivhaus certification

Architype’s expertise in Passivhaus, alongside Willmott Dixons’ flexibility in construction has helped to deliver a very low-energy building, with optimum internal conditions which hope to save as much as 90% on its heating bills.

Each room is served with a very small domestic scale radiator and light sensors to help students and teachers know how to use the room’s minimal light and heating most efficiently. The school has achieved an exemplary air leakage score of 0.3ACH, and is in the process of gaining Passivhaus certification.

Additional sustainability information

Embodied carbon over 100 year life / 1,798 kgCO₂eq/m² (including carbon sequestration)
Embodied carbon / 698 kgCO₂/m²
Operational carbon / 11 kgCO₂/m²/yr
Whole life carbon / 11kgCO₂eq/m² over 100 year life 1100kgCO₂eq/m²
On-site renewable energy generation / 10%
Airtightness at 50pa / 1.9m³/hr/m²
Heating and hot water load / 11.25 kWh/m²/yr
Total energy load / 28.06 kWh/m²/yr
Overall area-weighted u-value / 0.246 W/m²K (including glazing and thermal bridges)
Carbon emissions (all) / 11kgCO₂/m²
Predicted design life / 100 years