Wearing the crown better:
Looking to do more with
what's up top
Our starting point for the rooftop for Meta’s new office in King’s Cross was to design the landscape we wanted to see and then work out the routes for circulation, space for amenity and access to building facilities.
We all know that when it comes to nature loss in the UK, things are bad. That Britain has lost more of its natural biodiversity than all of the G7 nations and is ranked 12th lowest of 240 countries might still, however, come as a shock to many.
Clearly, the UK’s wildlife, plants and pollinators need helping hands – and fast. We also need to reduce carbon consumption and emissions if we are to get close to 2050 net zero targets. This means thinking much harder about the role of new development.
A quick scan of UK city skylines – Manchester, London, Liverpool, for example – highlights how much they are changing. With this comes challenge, and searching questions around how we build – demolition or retrofit, as well as who are we building for and social equity.
But changing skylines also bring opportunity. How can new build help to restore natural ecosystems? Should we be taking what happens on our rooftops more seriously?
The topic is timely. The University of Cambridge has hit the headlines for securing the consent to install near to 500 photovoltaic panels on the lead roof of the 15th century King’s College Chapel. The BBC reported the Provost of King’s as saying that the panels will have minimal visual impact but will make a considerable difference to decarbonisation “meeting 100 per cent of the energy needs of the building and reducing the college’s carbon emissions by more than 27 tonnes each year.”
The argument for green and brown roofs to support urban nature recovery is a powerful one. In London, roof gardens now cover an area larger than Hyde Park, but it’s not enough.
LDA Design’s ‘Living in the Landscape’ report put a restored blue and green network at the heart of a healthier Thamesmead. It baked resilience to climate breakdown into the vision, with biodiverse roofs designed to temper summer heatwaves. It is part of a programme to ensure Thamesmead becomes a pioneer for London in terms of biodiversity, with a grey to green approach providing new spaces for wildlife.
And in King’s Cross, crowning 11-21 Canal Reach, the primary new office for Meta by Bennetts Associates, we have designed a substantial rooftop landscape featuring species typically found alongside rail verges. There are wildflower meadows, brown roof, log piles, native plant species and plants for pollinators. It is the largest roof garden on the successful King’s Cross estate.
We wanted to bring people into close contact with nature at Canal Reach, in spaces that are rich in ecological value. So, our starting point was to design the landscape we wanted to see and then work out the routes for circulation, space for amenity and access to building facilities.
Over half of the buildable rooftop area is richly planted, making a significant contribution to the building’s BREEAM ‘Outstanding’ rating as well as supporting the London Borough of Camden Biodiversity Action Plan. Irrigation is used sparingly, and only during long, hot periods.
Biodiverse rooftops can help to stabilise bee and other insect populations. That’s why the city of Utrecht in the Netherlands has introduced a ‘no roof unused’ policy in which every roof will now be greened with plants and mosses or have solar panels.
Rethinking roof space is not without its technical challenges and it takes close collaboration between architects, structural engineers and landscape architects to tackle the various constraints that come with creating an impactful rooftop landscape.
For Canal Reach, we had to build up the soil sufficiently to ensure the planting could thrive. Solutions included raising the level of the floor to the centre of the main terraces by designing in ramped areas. Where even greater depth was needed, we created linear ‘berms’, mimicking rail-side landforms allowing suitable depth for trees.
The way forward for the built environment has to include maximising the potential of every square inch of new development to benefit people and planet, as well as more historic buildings looking to the roof level for answers.
