Turing House School, Twickenham: A 1,500m² Modular Wildflower Green Roof for a New Build School

This new-build school in South West London required a green roof spanning more than 1,500m² — a significant scale compared to many previous domestic and smaller commercial installations. At Turing House School, the ambition was not simply to install a green covering, but to create a thriving, sustainable rooftop landscape that would deliver long-term environmental and educational value.

Wallbarn worked closely with the main contractor, Bowmer & Kirkland, alongside appointed landscaping specialists Kingston Landscapes, to design and deliver a fully established modular green roof system within a tight construction programme.

A Complex Rooftop Environment

The roof space was divided across multiple levels, incorporating services, wiring and ductwork throughout. Walkways and angled parapets added further complexity to the layout.

The key objectives were clear:

• Protect the single-ply waterproofing membrane

• Deliver measurable environmental benefits

• Contribute towards BREEAM performance targets

• Provide a space that could serve as an educational focus once the school opened

Given strict project deadlines, the green roof needed to be established, healthy and quick to install. Wallbarn’s M-Tray® Wildflower modular system proved to be the ideal solution.

Fast, Efficient Delivery and Installation

One of the major advantages of the M-Tray® system is its modular format. Each 500 × 500mm tray arrives pre-grown and pre-established, allowing for immediate impact upon installation.

Modules were stacked onto pallets and delivered by articulated vehicle for efficient offloading. On-site logistics were carefully managed:

• A heavy-duty forklift positioned pallets ready for lifting

• A large cherry picker hoist transported full pallet loads to roof level

• Each articulated load of over 600m² was lifted onto the roof within a matter of hours

This rapid lifting process significantly reduced the time sedum and wildflower plants remained stacked, helping maintain plant health and vitality.

Once on the roof, pallets were lowered onto trolleys and moved directly into position for immediate installation.

Seamless Modular Integration

The M-Tray® system is designed with interlocking clips and notches within the module walls. Each tray simply clicks into place with the next, creating a continuous, seamless green roof without visible gaps.

Every module includes:

• A base planting scheme of hardy sedum varieties

• A diverse selection of native wildflowers and herbs

Even though installation took place in November, flowering plants were still visible, and bees and butterflies were already being attracted to the roof. This immediate biodiversity benefit reinforced the sustainability goals of the project.

Integrating Green Roof and Solar Energy

Sections of the roof were allocated for photovoltaic panels to generate renewable energy for the school. The modular nature of the M-Tray® system allowed the 500 × 500mm units to be laid neatly between PV arrays.

This approach enhanced overall sustainability while retaining accessibility. Should future maintenance be required:

• Individual trays can be lifted easily

• Wiring and services beneath the panels remain accessible

• PV units can be serviced or replaced without disturbing large roof areas

In contrast to roll-out green roof systems — which would require substrate and drainage layers to be excavated — the modular system offers superior flexibility and long-term practicality.

Environmental and Educational Value

Over the winter of 2021 and into spring 2022, the green roof matured and established itself fully. Plants grew together to form a cohesive and lush landscape across the entire 1,500m² area.

The transformation is striking. What could have been a vast, grey single-ply surface exposed to heat and weather has become:

• A natural insulating layer

• A protective covering for the waterproofing membrane

• A biodiversity haven

• A visually uplifting landscape

The roof now provides habitat for pollinators and contributes to urban greening within the Twickenham area.

Importantly, the space also holds educational potential. As pupils begin to use the building, the green roof may serve as a live demonstration of sustainability in action — illustrating ecology, renewable energy integration and environmental stewardship in a real-world setting.

Meeting Tight Deadlines with Proven Systems

Large-scale green roof installations can present logistical and coordination challenges, particularly on multi-level school buildings with ongoing construction works. However, the modular M-Tray® system allowed for:

• Rapid installation

• Reduced plant stress during delivery

• Minimal disruption to other trades

• Immediate visual impact

Feedback from the head teacher, Kingston Landscapes and Bowmer & Kirkland has been extremely positive, with all parties expressing satisfaction with both the installation process and the finished result.

A Natural Space in the Sky

As the school prepares to welcome pupils, the rooftop stands as a vibrant, living landscape. Beyond its aesthetic value, the roof provides measurable environmental benefits, insulation, membrane protection and biodiversity enhancement.

This project demonstrates how modular green roof systems can be scaled successfully to large new-build developments, meeting environmental targets while remaining practical and efficient to install.

The transformation of Turing House School’s rooftop proves that even large, complex roofscapes can become thriving natural environments — delivering long-term sustainability and a lasting positive impact for generations of students to come.

To view the full case study, please click here.