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Research and Briefing

A Proposal for Greening Our Cities


Planners are mandating more green areas in city centers to combat climate change and bring environmental benefits. In the seventh edition of our construction magazine Building Sight, we look at how the construction industry is tackling environmental issues and aiding countries to reduce emissions and meet ambitious targets.

New developments in London will have to provide an agreed amount of greenery if proposals in the draft London Plan go ahead.

The plan is introducing an Urban Greening Factor (UGF) in a bid to improve the quality of the city environment and fight climate change impacts.

The UGF is a version of the green space factor that was pioneered in Berlin 25 years ago. In the last five-to-ten years, a handful of other cities — including Malmö, Seattle, Helsinki, Washington DC, and Southampton in the UK — have adopted similar schemes, as concerns over the environment mount.

Introducing more greenery into urbans spaces brings a raft of benefits.

Green cover such as roofs or planted areas helps manage rainwater at source, reducing the risk of flooding.

Greenery also reduces urban heat island effects, encourages biodiversity, improves air quality, and contributes positively to the well-being of people living and working in cities.

Owners and contractors must be diligent in selecting the right systems and suppliers, however.

Green roofs or walls must be correctly specified and installed and — crucially — there must be a proper understanding of the maintenance requirements once a building is in use.

The green space factor is calculated by multiplying the proportion of a plot covered by greenery by a factor between one and ten, depending on the type of green cover, and adding those together to get an overall factor.

Planners can use these to set different target factors, depending on the use of the site or its location.