Project Team

Project Academics

Prof Nigel Dunnett
My focus in this research is to investigate the potential of vegetation and planting on roof and building surfaces. Research ranges from work with native plant communities and species, through to vegetations composed entirely of non-native plants – and all combinations in between. We are currently undertaking a wide-ranging screening programme of grasses and perennials for green roof use to test tolerance of substrate depth and moisture regime. Particular focus is on species from dry meadow communities in the UK, North America and continental Europe, and in plants from calcareous grasslands across the temperate world. Other work is investigating the long-term dynamics of green roof systems, and exploring the influence of vegetation type on green roof performance.

Research opportunities exist for work on all aspects related to green roof ecology, planting and implementation. Currently the departmental green roof team consists of three PhD students, five Masters projects, and a dedicated technician, and a wide range of test, research and demonstration roofs are available. Strong links are established with regional local government and development agencies, and active research collaborations exist with green roof teams in China and North America.

Dr Virginia Stovin
Virginia's work focuses on the use of computational fluid dynamics to optimise the design of combined sewer overflows and other sewer ancillary structures. This requires both the flow field and pollutant transport (sediment or solute) to be accurately modelled, increasingly in three-dimensions and in response to time-dependent inputs.

More recently her research has focused on sustainable urban drainage systems (SUDS), in which the retention of rainfall at source may assist in the control of urban flooding and sewer discharges. She is leading work in the UK on the potential to retrofit SUD systems into existing catchments, and is part of the Sheffield-based Green Roof Centre.


Dr Christian Berretta
Christian is the senior Research Fellow on the project, with a  background in urban drainage modelling. 

Dr Zoe Dunsiger
Zoë is lead researcher responsible for plant trials as part of the Marie Curie Green Roof Systems program. She has wide experience in field research in crop and ornamental plants. Her research background is in soil, water and plant systems in urban and peri-urban environments.

Dr Tobias Emilsson
Tobias Emilsson has a background in Plant ecology and a PhD in technology focused on Extensive green roofs. Tobias has extensive field work experience from arctic and roof ecosystems.

Project Partner Lead

Ralf Walker
Ralf is the Head of R+D at ZinCo GmbH in Germany and has undertaken lots of developments in the field of greenroofs. His background is in horticultural engineering, soil science and plant nutrition as well as in plants. The responsibility within the project is to lead the work carried out in Germany.

Project Researchers

Jorg Werdin - ZinCo secondee

Ruzica Mohorko - ZinCo secondee
Ruzica's background is in Landscape Architecture (University of Belgrade, Serbia). Before she came to Sheffield worked at ZinCo, one of the world´s biggest green roof system manufacturers, in the technical department .

Ruzica is an Early Stage Researcher on the Marie Curie funded project, with particular responsibility for the vegetation research.

Christine Thuring - PhD researcher
Christine has begun her research programme on the development of calcareous grasslands on green roofs. Of particular focus is the way in which the substrate and maintenance can influence the establishment of these grassland types in this environment. The maintenance of existing green roofs and their progression in a process of succession is an aspect of the work on long-standing roofs in Germany.

Gianni Vesuviano - PhD researcher
Gianni is studying aspects of the build-up or construction of green roof systems, in particular the role of the drainage layer in the roof hydrological performance. He contributes to research on rainwater runoff from green roofs and water holding capacity of green roof substrates.

Fred Sonnenwald - PhD researcher