Amongst the talks at the Green Architecture Event on Saturday was one on green roofs, given by Jeff Sorrill of the Green Roof Centre. Amongst the things I learnt was that you don’t want too much organic matter on your roof- an 80:20 to 90:10 mix of rubble and soil is best- because then only the hardiest plants can survive on it. Make your roof too nutritious and you run the risk of getting larger plants with more active roots that will push the weight limits and try to work their way into your building.
A section of green roof was brought along in a fish tank and set up on a table.