17th July 2025

The Green Prescription: Engineering Biodiversity Net Gain in Hospital Design

By Amy Norman, Senior Civil Engineer; Charles Rothnie, Senior Structural Engineer; and Ben Gillham, Graduate Structural Engineer, at Perega.

For too long, construction has been seen as a disruptor of the natural world. But as we become more aware of the urgent need to protect our planet’s biodiversity there’s a growing expectation for our buildings, even essential ones like hospitals, to tread more lightly on the land. Structural and civil engineers have a professional duty to move beyond mere carbon accounting and actively champion the integration of biodiversity within healthcare infrastructure.

The legislative push for a 10% Biodiversity Net Gain (BNG) on new developments across the UK^[1] is a welcome directive, compelling healthcare providers to consider ecological uplift. However, as Ben Gillham, a Graduate Structural Engineer at Perega, explains, “We need to consider the whole picture. The way we source and use materials like steel and concrete has a huge impact on global wildlife, often far beyond the building site itself.”

The operational realities of healthcare estates, which are often brownfield sites with inherent spatial and budgetary constraints, present unique challenges to ecological integration. Finding room for nature can feel like a luxury. As Charles Rothnie, a Senior Structural Engineer at Perega, points out, “It’s not always easy to find space for green areas on busy hospital sites. We need to be creative and think about how we can integrate nature right from the start of a project.”

^{Blossom Court, St Ann’s Hospital – Photo Credit: Tim Crocker}

While there’s often a desire to include green spaces, they can often be seen as less important when budgets are tight. However, bringing nature into healthcare is no longer seen as a ‘nice-to-have’ but a vital part of creating holistic healing environments.

From frame to flow
From an engineering perspective, there is a wide range of opportunities to weave nature into the very fabric of healthcare buildings and their site masterplans.

According to Charles Rothnie, “The initial site appraisal must meticulously map existing vegetation. Collaboration with arboricultural consultants is vital in informing the building footprint and massing. Employing a sensitive foundation design that suits specific site conditions. For example, a lightweight structure with nearby trees might benefit from using a smaller diameter pile solution, rather than mass spread foundations. Furthermore, a thorough understanding of the site’s hydrology and proposed drainage strategy is crucial to prevent adverse impacts on established ecosystems.”

Amy Norman, a Senior Civil Engineer at Perega, champions the adoption of Sustainable Drainage Systems (SuDS) as a basis of biodiverse design. “SuDS, encompassing features such as swales, ponds and green roofs, offer a dual benefit: effective stormwater management and the creation of microhabitats. The selection of hydrophytic planting within these systems supports diverse aquatic life and enhances local ecology. Crucially, integrating SuDS early in the site layout is not necessarily a cost premium over conventional buried pipework and attenuation tanks, and the aesthetic and well-being benefits these can bring are significant.”

Minimising ecological disruption during the construction phase demands meticulous planning of the works programme. Phased development and adherence to ecological constraints, such as avoiding vegetation clearance during bird nesting seasons, are essential best practices.

The healing power of biodiversity
The integration of biodiversity within healthcare environments provides more than just improved aesthetics, it also offers tangible benefits to patient recovery and staff well-being. Amy Norman highlights the multi-layered advantages of biodiverse SuDS: “These green infrastructure assets can not only manage surface water runoff, but also create visually appealing and tranquil outdoor spaces, creating a sense of calm and promoting mental well-being. Their reduced maintenance requirements and lower whole-life carbon footprint further enhance their sustainability credentials.”

In addition to this, Charles Rothnie emphasises the inherent link between efficient structural design and global biodiversity. “Optimising structural spans, employing lean design principles, and minimising material wastage at the fabrication stage directly reduce the demand for resource extraction. Avoiding over-engineered solutions is not just beneficial from an economic standpoint, but an ecological one too.”

Ben Gillham added: “Several studies suggest there is a positive correlation between access to natural light and green spaces and improved patient outcomes^[2], including reduced hospital stays and decreased analgesic requirements, reinforcing the clinical rationale for ecological integration.”

Navigating the challenges
Biodiversity-focused visions within healthcare projects can present several challenges that call on innovative engineering solutions. A key tension, as Charles Rothnie explains, lies in balancing the ecological benefits of features like green roofs with the increased dead load and consequent embodied carbon of the supporting structural frame. “While a sedum roof or a more intensive brown roof can significantly enhance local biodiversity, the additional imposed loads necessitate a robust structural solution. Early engagement allows us to strategically locate these features over areas with shorter structural bays or inherent structural capacity, mitigating the need for excessive material use.

Charles also highlights the frequent challenge of accommodating essential plant rooms within hospital designs. “Plant equipment demands a significant amount of space, and these rooms are often located on roofs. This directly competes with the potential for green or brown roofs, making their integration a complex planning exercise.”

Adding to this, Amy Norman reiterates the spatial constraints of existing hospital sites. “Necessitating inventive, multi-functional landscape designs are vital in making the most of the provided plot for extension or refurbishment of healthcare estates. The healthcare industry needs to move past ingrained attitudes towards perceived cost and time implications of green initiatives. However, to do so requires holistic value engineering that considers not just the initial upfront cost, but also the long-term ecological, well-being, and financial benefits over a system’s entire lifespan.”

Exemplars of integration
While the widespread adoption of deep ecological integration in UK healthcare is still nascent, notable examples offer a glimpse of the possibilities. Ben Gillham highlights the Maggie’s Leeds Centre^[3], where an accessible green roof provides a therapeutic sanctuary for patients and staff and patients are encouraged to care for its 17,000 plants.

Ben adds, “While the widespread adoption of deep ecological integration in UK healthcare is still nascent, notable examples offer a glimpse of the possibilities. However, it’s important to acknowledge that green roofs, while beneficial for local biodiversity, come with considerations such as higher imposed loads, which necessitate larger structural members and increased material usage, consequently impacting global biodiversity and raising the carbon footprint. Research^[4] has indicated that the payback time for a green roof’s production and maintenance can range from 5.8 to 15.9 years, a figure that doesn’t account for the increased material usage in the supporting structure.”

Furthermore, Ben points to the adaptive reuse of existing structures, such as the NHS Dorset Health Village, an outpatient assessment centre on a vacant floor within a department store incorporated 70% of equipment and materials from a decommissioned Nightingale Hospital^[5], exemplifying a resource-efficient approach with inherent biodiversity benefits by avoiding greenfield development.

In addition to this, Amy Norman champions the integrated SuDS at the Midland Metropolitan University Hospital which use the blue network of local water systems and canals^[6], showcasing how essential infrastructure can simultaneously enhance biodiversity and create amenity-rich green spaces.

Building a greener, healthier future
While architects work closely with user groups to develop optimal layouts for clinical staff and patients, as well as the aesthetic of the health estate, civil and structural engineers are pivotal in partnering with such stakeholders to deliver truly sustainable and ecologically sensitive healthcare infrastructure. By embedding the principles of biodiversity net gain from the strategic brief through to detailed design and site execution, the healthcare industry can move beyond a purely functional approach to create healing environments that nurture both people and planet.

Prioritising the preservation of existing ecosystems, minimising material consumption through intelligent design, and embracing innovative green infrastructure solutions should not be afterthoughts that are eventually parked further down the line, but implemented into the DNA of the building from the offset.

[1] https://www.gov.uk/guidance/understanding-biodiversity-net-gain

[2] https://ccbp.org.uk/designing-for-wellness-the-impact-of-innovative-hospital-construction-design-on-patient-experience/

[3] https://www.archdaily.com/941540/maggies-leeds-centre-heatherwick-studio

[4] https://www.mdpi.com/2071-1050/10/7/2256

[5] https://www.nationalhealthexecutive.com/articles/video/university-hospitals-dorset-become-first-nhs-trust-launch-think-big-project

[6] https://worldlandscapearchitect.com/nature-inspired-healing-at-midland-metropolitan-university-hospital/?v=b870c45f9584