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Call 020 8916 2222Healthcare environments demand some of the highest standards of safety, compliance, and technical performance found in any building type. When a project seeks to introduce something entirely new into this environment, the challenge becomes even greater. This was precisely the case with the development of a fully operational rooftop Critical Care Unit (CCU) garden at King’s College Hospital in London.
Designed as an extension of the hospital’s world-class CCU, the 170 sqm rooftop space allows critically ill patients to experience fresh air, daylight, and nature without disconnecting from life-supporting medical equipment. While the therapeutic benefits of such a space are clear, delivering it required a carefully engineered solution capable of meeting strict regulatory, structural, and clinical requirements. Projects such as this rooftop CCU space for King’s College Hospital case study demonstrate how innovative systems can successfully be implemented in highly sensitive environments.
The project stands as an example of how technical innovation, collaboration, and specialist materials can make ambitious healthcare design possible.
Turning a Vision into a Practical Design
The original concept for the rooftop garden came from Dr Tom Best, Critical Care Clinical Director at King’s College Hospital. His aim was to create a safe outdoor environment where patients receiving intensive care could experience the restorative effects of nature.
However, transforming this vision into reality required solving several complex technical challenges. The roof space above the CCU had historically remained unused because of the difficulties associated with converting it into a compliant outdoor environment.
Key issues included:
- Fire safety regulations
- Structural loading limits
- Integration with critical medical infrastructure
- Access for installation and maintenance
- Safe movement of vulnerable patients
- Each of these factors had to be carefully addressed to ensure the finished space could operate safely as part of an active hospital environment.
Meeting Strict Fire Safety Regulations
Fire safety was one of the most critical aspects of the project from the outset. Because the rooftop space sits above a functioning hospital and would be used by vulnerable patients, it had to comply fully with Building Regulations Approved Document B, which governs fire safety in buildings.
To meet these requirements, the design team specified a fully non-combustible decking and planter support system. Systems such as non-combustible porcelain decking are essential in these environments, offering both aesthetic appeal and the highest levels of fire performance.
Early in the design process, composite decking materials were ruled out because they could not achieve the required fire performance classification.
Instead, the project required materials capable of achieving Class A fire performance, the highest level of fire resistance available for external surfaces.
This requirement shaped many of the design decisions and ensured the finished installation would meet the stringent standards expected in healthcare environments.
Specialist Decking Design and Technical Support
Wallbarn became involved in the project at an early stage through their long-standing partnership with AB Building Products, who were supplying the fire-rated decking boards used in the scheme.
The selected product, Exadeck, provided a heavy-duty, non-combustible decking surface designed specifically for environments where fire safety is essential. This type of solution works in conjunction with robust structural systems such as a Class A1 rail substructure system, ensuring full compliance while maintaining flexibility in design.
Wallbarn’s role focused on providing the technical substructure solution that would support the decking and planters while accommodating the complex layout of the rooftop garden.
Their design incorporated a system that could deliver:
- Structural strength
- Precise height adjustment
- Long-term durability
- Easy access to services beneath the deck
- Full compliance with fire safety regulations
This combination of performance characteristics made the system well suited to the demands of a healthcare setting.
Accommodating Critical Infrastructure Beneath the Deck
One of the most technically challenging aspects of the project was the extensive network of medical services located beneath the rooftop surface.
Because the garden sits directly above the Critical Care Unit, the area contains numerous essential service routes. These include:
- Medical gas supply lines
- Electrical power systems
- Data and communications networks
- Monitoring and control equipment
Protecting these services while maintaining full access to them was essential.
To achieve this, the design utilised a suspended decking system supported by adjustable pedestals. This approach created a void beneath the deck where services could be safely routed while allowing airflow and drainage. Systems like those used in the Class A1 rail substructure system are particularly effective in delivering this level of flexibility and structural reliability.
Equally important was the ability to maintain and access equipment when required. For this reason, the design incorporated strategically placed access hatches within the deck surface.
These hatches allow engineers and hospital staff to reach service controls without dismantling large areas of the deck, significantly improving operational efficiency.
Materials Designed for Longevity and Performance
The final decking system combined several components chosen for durability and long-term performance.
These included:
- MetalPad Ex steel pedestals featuring Zintec 200 anti-corrosion coating
- High-grade extruded aluminium rails and joists
- Class A rated fixings and connectors
- Heavy-duty Exadeck fire-rated boards
Together, these elements created a robust system capable of supporting the rooftop environment for decades. High-performance systems, including non-combustible porcelain decking, are designed to maintain both structural integrity and visual quality over time.
The materials selected are designed to deliver a life expectancy of more than 50 years, making them particularly suitable for healthcare infrastructure where reliability and minimal maintenance are essential.
Installation Expertise and Detailed Site Surveys
Once the design phase was complete, ISW UK Ltd were recommended as the preferred installer due to their experience with complex rooftop construction projects.
Before installation began, the contractor carried out a comprehensive roof survey. This survey revealed several differences between the original design drawings and the real-world conditions on site.
These discrepancies included measurement variations and build-up tolerances that could have affected the installation process.
By identifying these issues early, the team was able to revise the design before materials were ordered. Wallbarn updated layouts, quantities, and quotations based on confirmed site dimensions.
This collaborative process delivered several key benefits:
- Avoiding installation errors
- Preventing material waste
- Reducing the risk of delays
- Lowering overall project costs
The result was a fully coordinated design ready for efficient installation.
Managing Access and Logistics on a Live Hospital Site
Another major challenge involved transporting materials and equipment through a busy hospital environment.
To complete the installation, certain staircases and access areas within the building had to be temporarily dedicated to the project. Because these spaces are essential to hospital operations, the construction process had to be carefully managed to minimise disruption.
Material deliveries were organised to ensure efficient handling and movement throughout the building.
The decking boards and pedestal systems were supplied on standard Euro pallets, allowing them to be transported through internal routes more easily.
Meanwhile, the 3.6 metre aluminium rails were supplied on larger pallets but remained lightweight enough to be carried safely by a single installer, improving handling efficiency during the build.
Collaboration Across Multiple Disciplines
The success of the project relied heavily on collaboration between specialists from several disciplines.
The project team included:
- Malcolm Hankey of Bluelight Management, overseeing delivery
- BMJ Architects, responsible for architectural design
- Professor Nigel Dunnett, leading the landscape design
- WSP and Ross & Partners Ltd, providing engineering consultancy
- ISW UK Ltd, delivering the installation
Through close coordination between architects, engineers, contractors, and suppliers, the team delivered a solution that satisfied both technical performance requirements and clinical needs.
A Technical Benchmark for Future Healthcare Projects
The rooftop CCU garden at King’s College Hospital is more than a successful construction project. It demonstrates how innovative engineering solutions can unlock new possibilities in healthcare design.
By overcoming complex structural, safety, and logistical challenges, the project team has created a space that improves the patient experience without compromising clinical safety. Insights from projects such as the King’s College Hospital rooftop CCU case study highlight how these solutions can be applied effectively in similar environments.
As hospitals continue to evolve, projects like this show how unused rooftop spaces can be transformed into valuable therapeutic environments.
The result is a powerful example of how engineering innovation and thoughtful design can work together to improve patient care, setting a new standard for healthcare infrastructure in the UK.
