Adding a Green Roof
A green roof is one with plants growing on its surface. This could range from a spontaneously occurring moss and lichen covered roof to a full-scale roof garden that includes trees, shrubs and hard landscaping features.
One of the most interesting projects I have been following with a keen interest is the highline project. The High Line is located on Manhattan’s West Side. It runs from Gansevoort Street in the Meatpacking District to 34th Street, between 10th & 11th Avenues. Section 1 of the High Line, which opened to the public on June 9, 2009, runs from Gansevoort Street to 20th Street.
The practice of roof planting in Europe is at its most technically advanced in Germany where green roofs have been fundamentally divided into two categories, intensive and extensive.
Intensive green roofs are roof gardens and like any garden provide space for people. They require the intensive management of a ground level garden, are usually based upon a thick soil or substrate layer and require artificial irrigation. Preferred plants are selected and the roof conditions created to support them. They are heavy systems and thus can have major structural implications for the building.
Extensive green roofs are not usually recreational (although extensive planting can be integrated with intensive systems). They have low management requirements and do not usually require artificial irrigation. Plants are selected that will succeed with only minimal modification of the normal roof conditions. Planting styles are usually naturalistic with the objective of establishing a self-sustaining plant community on the roof. Based on a thin layer of soils or substrates, they are lightweight systems with minimal structural implications for the building. The main reasons for installing an extensive green roof are visual appeal, reducing the environmental impact of the building, creating habitat for native flora and fauna, and enhancing building performance.
We recommend www.greenroof.co.uk as used by us at Hampton Court 2005