Green roof is a general term for any roof covered with a growth substrate with plants growing on it, and as such, green roofs vary enormously in their type and function. They are generally split into two main types: intensive green roofs, which are essentially roof-top parks and gardens, which are characterised by deep growth substrates, high maintenance and high costs; and extensive green roofs, which are characterised by thin growth substrates, low maintenance and lower costs; but both of these terms encapsulate a huge array of roof types. The term brown roof has been used in a variety of contexts, but is here used to describe a type of extensive green roof that is designed to mimic brownfield sites at an early stage of succession. When choosing a type of green roof it is very important to realise that the way a roof is designed will influence the environmental benefits associated with that roof, and that designing a roof to maximise one environmental benefit can potentially trade off against other environmental benefits.
The most important environmental benefits associated with green roofs are: the thermal insulation of buildings, increased roof longevity, urban cooling, improved urban aesthetics, reduced roof run-off, and habitat creation. This project mainly aims to: (1) develop a strong scientific understanding of the ability of brown roofs to (a) act as substitute brownfield habitat and (b) reduce roof run-off, and (2) share this understanding with practitioners and the general public through workshops and demonstration projects. In most countries at the moment, green roofs are often seen as quirky projects associated with environmentalists. This will remain the case until the development of a depth of scientific understanding of the environmental benefits of green roofs and the way they trade off against each other, and practitioners and the public are more widely familiar with the green roof concept. Only when these two barriers to the uptake of green roof technology are removed will green roofs be used on a large enough scale to really make a difference to the multiple environmental problems facing urban areas.
This web page currently contains details of two brown roof demonstration projects in Birmingham’s city centre, the BVSC (Birmingham Volunteer Service Council) brown roof, and the ICC (International Convention Centre) brown roof, but more are likely to follow. Information on the ecology and development of these roofs will be updated as and when it is available, so please keep visiting this site. Importantly, lists of species using the roofs and monthly photographs of the development of each roof will be posted here. There is also a summary page covering various green roof workshops and tours that we have helped organise. Understanding which species are likely to use a roof, and how green roofs really look at all ages and different stages of the year is a crucial factor when deciding what type of green roof to choose.
If you would like more information on either of these brown roof demonstration projects, or you are in the Birmingham area and would like advice on designing and building green roofs, then please contact Dr Adam Bates in the first instance using the contact form below.