DeepDive: Climate benefits and community when the rooftops go green

As our towns and cities expand, nature is being pushed aside and the consequences of this are becoming increasingly clear. Pollution in the air, land and water, harmful noise and biological imbalance are some of the clear downsides of urbanisation. As are loneliness, ill health and stress-related illnesses. At the same time there is tremendous untapped potential if we turn our gaze upwards. Green roofs enable us to increase vegetation in densely populated towns and cities. Where today there are rooftops, tomorrow we could find flowering meadows, fruit trees, parks, vegetable crops, soft moss – and togetherness.

“Green roofs are socially smart, fun and educational. What’s more it’s relatively easy to grow edible plants. Greenery, whether it’s on a roof or on the ground, is key to maintaining contact with nature. And in times like these, the outdoor environment is particularly important, as is planning solutions that enable us to spend time amongst greenery, even though we are at home. Solutions that make greenery part of our everyday life,” says Ulrika Bergbrant, landscape architect LAR/MSA at White.

Ecological and social benefits
According to Sweden’s environmental quality objectives, the country’s municipalities must work with ecosystem services and urban greenery in the planning, construction and management of the built environment by 2025 at the latest. There is a lot to be gained for municipalities that take the objective seriously. Plant-covered façades, green courtyard environments and roof gardens can transform previously underutilised spaces into green lungs from which we can draw energy.

A green roof reduces the pressure on a town or city’s surface water system as the roof captures the rainwater and significantly reduces the run-off water. This is one positive from a climate perspective, but there are more. The vegetation on the roof uses solar energy to grow, and the sun’s rays are therefore not converted into heat. A green roof also reflects more of the sun’s rays than a roof with dark waterproofing layers, and this contributes to lower surface temperatures. It benefits the local microclimate when the roof does not emit unnecessary excess heat. Virtually all types of green roof contribute to a cooling effect in the summer and help lower a building’s energy consumption. In addition, research shows that some types of green roof with thick planting beds provide extra insulation. Green roofs also promote richer flora and fauna, where pollinating insects, such as bumblebees and bees, find nectar and, in some cases, even entire habitats.

Making room for greenery is also a wise investment in public health. Research shows that people feel better when they regularly surround themselves with greenery in their everyday lives. In green environments our cortisol levels, heart rate and anxiety all decrease. A green roof also reduces noise levels, which in itself contributes to increased well-being for animals and people. Research shows that green environments stimulate more social togetherness among people. To plan for connected quality green areas is to plan for a more sustainable living environment.

Natural community amongst the greenery

On Smörslottsgatan in Gothenburg, a unique roof landscape has sprung up which captures the very essence and diversity of nature. The roof terrace is characterised by clever partitioning into different spaces and functions. Open social rooms and communal seating areas have been supplemented with quiet, separate places for recreation. The conservatory provides shelter if the weather is bad or if you want to sit down in more seclusion, and tall hedges divide the private patios. The focus, however, is mainly on the informal areas for socialising, which can hopefully promote a richer social life:

“Thanks to green roofs, our social lives can take up more space; beside the plants we meet neighbours and friends and share a hobby. We can also invite friends to socialise in a larger area than that offered by our homes. On Smörslottsgatan we have planned for both shade and sun and for different needs – ‘Do you want to sunbathe or harvest crops?’ The work on Smörslottsgatan has really shown us the importance of dividing a roof terrace into different rooms, which ideally can be achieved with green elements,” says landscape architect Ulrika Bergbrant.

The roof terrace on Smörslottsgatan is becoming a green view that links the building with the surrounding environment. Part of the site consists of a spectacular forest area, and the plants on the roof terrace have been chosen to link to the neighbouring forest environment and are accompanied by species hand-picked for their suitability in a sunny, dry climate. The ergonomic raised planting beds make the plants more visual, while the soil depth enables more species to be grown and improves the beds’ water-retention properties.

Next to the residential building on Smörslottsgatan, White has created a modern, close-to-nature pre-school, Smörslätten 1. So apart from the roof terrace bringing nature closer to everyday life for the neighbourhood’s residents, it also creates wonderful opportunities for outdoor learning for around 100 pre-school children. It has been important for the landscape architects at White to create an accessible outdoor environment that enables the children to get out into the neighbouring forest quickly and easily. The roof’s social spaces, with a pergola, conservatory and rolling landscape, are also designed so that the children can be outdoors even if it’s raining. The well-thought-out green roof terrace inspires new generations to spend time in nature, and perhaps it’s the city growers of the future who are growing up at Smörslätten 1.

“Greenery makes us feel good! Greenery gives us a sense of the variations of the seasons. We see signs of spring in the form of cherry blossom and spring bulbs, we get a sense of autumn from tree leaves turning orange and winter is felt with the flowering of the Christmas roses. And don’t forget that the greenery can also be useful! Especially when we grow edible crops. Currants, gooseberries, blackberries, strawberries, Jerusalem artichokes, chives, oregano, rhubarb and thyme are excellent choices for roof gardens! Hence the city roof also becomes a key component when we want to grow food locally,” says Ulrika Bergbrant, landscape architect LAR/MSA at White.