Up on the Roof

I am a big fan of roof gardens. Roof gardens can provide a spot of nature on an otherwise barren surface, can lower the air temperature by 15 degrees, and can help prevent water runoff. A pioneer of roof gardens is Theodore Osmundson, who defines roof gardens on page 13 of his book, Roof Gardens: History, Design, and Construction:

A roof garden is any planted open space, intended to provide human enjoyment or environmental enhancement, that is separated from the earth by a building or other structure. It may be below, level with, or above the ground. While it may serve other functions—as a means of circulation or access or as a dining space, for example—a roof garden’s primary purpose is to provide a place to be among or to view plants.

Some roof gardens are meant to be enjoyed by people – with many of the same elements as an-earth bound garden, such as plants, furniture, and structure. Other roof gardens are meant for utilitarian purposes – such as insulation, filtering water, or providing habitat for birds and insects. In either case, the roof must have the structural integrity to bear the load, special materials must be used to protect the structure, water and drainage must be provided, soil must be brought in and enriched, appropriate plants must be selected for the unique in-air microclimate, and safety precautions must be taken.

West Elm's attractive roof garden in Emeryville