One way of promoting green roofs and investigating the question of their accessibility is to look at some of the excellent examples which now exist.
Parliament House, Canberra is probably one of the world’s earliest and most successful green roofs. The Parliament House building was constructed in 1988 for $1.1 billion. The reason for the design of the green roof at the time was not due to sustainability as an imperative, rather it was conceived of “in order to preserve the shape of the hill on which it was built.” The Parliament building was constructed into the top of the hill and the roof was grassed over.
The issue of the grassed roof’s sustainability has been raised by the prolonged drought conditions of recent years. The architect of the original building, Romaldo Giurgola, is against all proposals to replant the roof with more sustainable hardy, native or drought tolerant plants. He believes that grass turf is an intimate part of the conception of the building and that any change “would completely destroy the form of the building.” http://greenroofs.wordpress.com/category/politics/
I suggest an online design competition to produce and debate alternative forms of cover which would satisfy the perceived need for a more sustainable ground cover and satisfy the demanding eye of the architect who rightly has regard to the heritage value of his work and to its design integrity.