By Mary James and Chayley Collis

Just moments away from the Tower of London, in a busy and compact urban location, sits the new Mulberry Academy London Docks School, a Passive House secondary school. The 93,000-ft² school stands as a striking civic landmark, respecting the area’s rich history and architectural character. Finished in 2024, it was recently certified by PHI.

The project’s site presented multiple challenges, starting with its size. The footprint of the site was significantly smaller than is normal for a secondary school that houses more than 1,100 students, which required the entire site to be utilized creatively. Strategies included the design of hall spaces below ground, six stories of building above ground, and outdoor and play spaces on the various roof terraces.

Creating a sense of connection to biodiversity and nature for students in this context—an important concern—was a particular challenge. A thoughtfully designed landscape strategy prioritizes ecology and wellness, integrating vibrant green spaces on terraces and façades to enhance student and community well-being. Internally, the innovative design continues with halls and multi-use games areas positioned at ground level and one level below, ensuring natural light and visual connectivity. Teaching and learning spaces occupy the upper floors, where generous glazing strengthens the connection to the outdoors. 

Although the busy road immediately to the north of the site is a major source of air and acoustic pollution, building to Passive House levels of performance significantly helped the school address these issues. The school’s outstanding airtightness—0.2 ACH50 in a building with a complex façade and large areas of curtain walls at the ground floor—and the use of an efficient heat-recovery ventilation system that draws in fresh air from five stories above ground was essential to achieving excellent air quality. Passive House also helped mitigate the acoustic concerns from the nearby roads.

As Rory Martin, senior architect with Architype, says, “The Passive House design also delivers particular benefits for air quality, with fresh filtered air, creating a natural defense against the nearby traffic. The complex site challenges, with an original dock wall and basement build on a busy road, demonstrate that Passive House and low carbon design can be achieved on the most challenging of urban sites. This is vital in the race to net zero.”

Hugh Pearce, architect and Passivhaus Lead with Architype, echoes the importance of the Passive House approach in achieving many of the project’s goals, saying, “Passivhaus was implemented to address air quality and noise challenges from the adjacent road while ensuring high construction standards. Enhanced airtightness, combined with fresh air drawn from high levels, creates a consistently comfortable and healthy environment for all users. Through its creative and sustainable design, Mulberry Academy London Docks provides an enriching space that not only supports academic excellence but also nurtures well-being, engagement, and a sense of belonging within the community.”

The good form factor allowed the project’s thermal performance requirements to be more easily met and created an unusually high allowance for thermal bridges in a Passive House building. The school has 548 W/K thermal bridges, which are responsible for 14% of the transmission heat losses.  One such thermal bridge was as a result of constructing a trellis that supports plant growth up the stair cores.

Efforts to reduce embodied carbon fortunately conflated with value engineering changes to incorporate post-tensioning concrete. The floor slab specification was reduced from a typical 300-mm (11.8 inches) reinforced concrete to 225-mm (8.9 inches) post-tensioned concrete, which significantly reduced the weight of the structure and the size of the required foundations. The project designers also sought to minimize embodied carbon by maximizing cement replacements and specifying concrete that cures at 56 days rather than 28.

To ensure the optimal delivery of fresh, filtered air, the building’s ventilation system has its supply controlled by temperature and CO2 sensors in classrooms. In addition, the system can provide peak low output power (lop) cooling, when required, which supports future climate resilience. Brise soleil shading is used above some of the school's glazing to provide summer shading. Air source heat pumps (ASHP) provide heating and hot water.

Managing Director David Rowsell of Kier Construction London sums up his firm’s experience with, and appreciation of, this cutting-edge project, saying, “This flagship Passivhaus school in London creates a low-carbon building and a healthy environment for the students, teachers, and local community. This school builds on Kier’s experience working on Passivhaus projects, having delivered seven for communities across the UK.”