(Image credit National Garden Scheme)
You wait ages for an outdoor critical care space to come along, and then two come along at once.
Quick summary: In summer 2026, King’s College Hospital and St George’s Hospital each opened outdoor spaces for critical care patients — including some on full life support — and both remained operational through extreme heat. Their success rests on six repeatable design and operational principles: solar shading, cross-ventilation, cooling planting, low-heat-storage materials, weather-resilient clinical infrastructure, and active operational protocols.
Backed by growing evidence on the role of daylight and nature in health, motivation and wellbeing, King’s College Hospital and St George’s Hospital each opened a new outdoor space this summer, just before the heat took hold. Despite extreme weather and ongoing pressure on the NHS, both spaces stayed open throughout. This piece looks at the design features that helped keep them running — and what they mean for NHS estates teams, planners and design teams considering similar spaces.
What is an outdoor ICU space, and why does it matter?
An outdoor critical care space is an area — a balcony, garden or roof terrace — where patients in intensive care can spend time outside while remaining under full clinical monitoring and support. For patients recovering from serious illness or injury, connection to daylight, greenery and the outside world isn’t a luxury; it’s linked to measurable clinical outcomes.
The evidence base here isn’t new. Roger Ulrich’s landmark 1984 study found that surgical patients with a window view of trees had shorter hospital stays (7.96 days versus 8.70 for patients facing a brick wall) and needed less pain medication. More recent ICU-specific research points the same way: one study found the incidence of delirium — a common, serious complication in critically ill patients linked to longer stays and higher mortality — was significantly lower among ICU patients in rooms with windows than those without (21.7% versus 43.3%). Genuine outdoor access takes that principle further than a window ever could.
What’s new: two UK-first outdoor critical care spaces
St George’s Hospital — Neuro-ICU Balcony Garden
This purpose-built balcony keeps patients safely within critical care while giving them time outside — described by staff as offering “a connection to the outside world after being beside lots of machines in intensive care.” It was developed in response to research suggesting nature-based rehabilitation can support recovery from brain injury by improving motivation, helping regulate mood, and supporting sensory-motor and cognitive function.
King’s College Hospital — Outdoor Critical Care Roof Garden
King’s opened the UK’s first outdoor ICU garden in May 2026. Patients remain on full life support outdoors, connected via weatherproof medical docking stations, in a garden designed to provide fresh air, greenery and daylight safely. Planting includes aromatic and tactile species — rosemary, sage, lamb’s ear — chosen for sensory engagement, and the clinical team is formally studying how outdoor exposure affects recovery, delirium, stress and length of stay.
Both gardens share a common thread: shaded, ventilated, vegetated design that kept them usable even during the hottest periods of the summer, backed by active staff management of exposure time — a key layer of heatwave resilience that design alone can’t provide.
Six design principles behind their heatwave resilience
1. Block the sun
Both spaces rely on shading and planting to cut direct solar gain — essential for both patient comfort and safe clinical operation. King’s rooftop garden uses overhead pergolas and a tree-like sculptural canopy to cast dappled shade over seating and bed areas.
- Use canopies, pergolas or tensile shade structures.
- Avoid high-albedo (highly reflective) paving near beds, which can increase glare and radiant heat.
- Provide seated shade for visiting families, not just patients.
- Build in cooling refuges — deep shade or ventilated corners — for the hottest parts of the day.
2. Keep air moving
Natural ventilation reduces heat stress and supports respiratory comfort — important for patients who may already have compromised breathing.
- Maintain open edges to allow cross-flow rather than enclosing the space.
- Avoid dense planting that blocks natural breezes.
- Combine shaded and well-ventilated zones rather than treating them separately.
- Consider moveable planting that can provide extra shelter outside heatwave conditions.
3. Use vegetation for cooling and sensory comfort
Planting at both hospitals does more than one job: it’s sensory, drought-resistant, low-maintenance, and supports cooling through evapotranspiration — the process by which plants release water vapour, drawing heat from the surrounding air as it evaporates.
- Choose drought-tolerant species with a high leaf-area index (more leaf surface per plant, which increases the cooling effect).
- Combine aromatic herbs — rosemary, sage, oregano — for sensory engagement and heat resilience.
- Include tactile planting, such as lamb’s ear, to support neuro-rehabilitation.
- Use planting to soften acoustics as well as temperature, reducing stress from noise.
4. Reduce heat storage and re-radiation
Dense, dark materials absorb heat during the day and re-radiate it later, raising mean radiant temperature (MRT — a measure of the total heat radiating onto a person from their surroundings, not just the air) and slowing evening cooling. St George’s balcony uses planting beds, vegetated edges and ventilated balustrades to limit this effect. King’s combines shaded seating zones with low-maintenance planting and non-glare surfaces, cutting both solar load and surface heat.
- Specify low-heat-storage materials: timber, composite decking, pale stone.
- Avoid dark, dense paving and reflective, glare-prone surfaces.
5. Build weather-resilient clinical infrastructure
King’s rooftop garden is the UK’s first space where patients on full life support can be outdoors — only possible because of purpose-built, weather-resilient infrastructure, including:
- Weatherproof medical cabinets for power, data and medical gases.
- Equipment rated for outdoor temperature swings.
- Safe transfer protocols for ventilated patients.
- Clinical-grade flooring and surfaces that remain safe in wet or hot conditions.
6. Manage it operationally, not just architecturally
Design alone doesn’t make these spaces heatwave-proof — active clinical management is what keeps them safe day to day. King’s uses explicit “weather-permitting” protocols:
- Time-limited exposure during the hottest periods.
- Continuous monitoring of patient temperature, comfort and equipment performance.
- Immediate fallback to indoor ICU beds if conditions change.
- Clinical judgement on which patients can safely tolerate outdoor conditions at any given time.
Key takeaways for future outdoor clinical spaces
King’s and St George’s demonstrate that outdoor critical care spaces are viable even during heatwaves — but only where microclimate design and clinical protocol work together, not as a substitute for one another. For NHS estates teams and design teams considering similar spaces, the transferable lessons are:
- Shade and ventilation have to work together, not as separate systems — one without the other undermines both comfort and safety.
- Planting should be doing several jobs at once: cooling, sensory engagement, and acoustic softening, not chosen for aesthetics alone.
- Material choice affects evening performance, not just daytime comfort — low-heat-storage materials matter as much after sunset as during peak heat.
- Clinical infrastructure has to be designed for the outdoors from the start — retrofitting weatherproofing onto standard equipment isn’t the same as specifying it as outdoor-rated from day one.
- Operational protocol is not optional — even a well-designed space needs active staff judgement on when and how it’s used during extreme weather.
As the climate continues to shift toward more frequent and intense heat events, spaces like these are likely to move from pioneering exceptions to a standard part of the critical care estate brief.
Sources
“Association of natural light exposure and delirium according to the presence or absence of windows in the intensive care unit,” PubMed, 2021. long-stay patients and can be part of future NHS resilience planning.
Ulrich, R.S., “View Through a Window May Influence Recovery from Surgery,” Science, 1984.