When former Mayor of Chicago Richard Daley proposed a garden on the roof of city hall in 2001, the idea was ridiculed. But 15 years later, that garden continues to improve the energy efficiency of the building by retaining rainfall in the soil and cooling the building from the top down. The garden roof was built to last twice as long as a traditional roof and has provided the city with praise-worthy scenery where there was once only tar. City Hall set an example, and now more than 200 other buildings in Chicago are topped with gardens.
Adding greenery on a home or building rooftop does have merit and the adaptive re-use of existing rooftops is becoming a common theme in urban redevelopment. The caveats are the structural capability of the roof to hold the additional weight and people, and safety railings. In most cases, it’s advisable to design gardens that are lightweight and moveable, for ease of long-term roof-top maintenance – a small urban set-up with a hydroponic garden on a home roof, with the liquid fertilizer provided by a small vermiculture (aka a worm farm) operation fed from food scraps from a local restaurant sounds rather appealing, doesn’t it?
Green roofs make sense both from the standpoint of reducing urban heat island effect and of providing more spaces to connect people to nature. Whether in new home or building design, or existing structural renovations, the potential for adaptive reuse as greenspace is certainly worth considering. This could mean setting up rooftop rain collection, installing dumbwaiters to bring the compost up to the roof, and providing water spigots and structural bases for future greenhouses or pavilions. Establishing the infrastructure for future scenarios is least expensive to install at the time of initial construction.
Click here to read more about Chicago City Hall’s rooftop garden.