RESEARCH: Using compost in green roof growing media

Posted 11 January 2010

Researchers at Harper Adams University College are investigating which inorganic materials make the most efficient green roofs when mixed with compost, an organic material.

Green roofs have been popular in Europe, particularly Germany, for many years thanks to their insulating properties and ability to reduce rain water run-off.

Abigail Graceson, a post-graduate research student at the University College, said: "At the moment we are studying the properties of different substrates such as crushed brick or tile mixed with compost, and have set up 36 one metre square decks to simulate roofs.

"These have been filled with the twelve different substrates, replicated three times each, and will show the amount of rain water run-off as well as which are the most suitable for growing sedum and meadow plants."

"Eventually, we would like to draw up a blue-print for the UK, looking particularly at flat roofs and which substrates produce the most successful plants in this climate. We also hope to investigate the physical and chemical properties and how these change between the inorganic and organic materials."

Harper Adams installed a green roof at the Companion Animal House in July 2008. Gaynor Orton, Business Development Manager, Sustainable Technologies, said: "We erected the sedum matting roof as part of our sustainability trail around campus.

"Other features include a photovoltaic solar array on college buildings, electric vehicles that assist with recycling and a sustainble building design in the Bamford library."

Watch the video to find out more about this WRAP and Vital Earth sponsored project.