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1. ROOF GARDEN
Concept
A garden on the flat roof of a building, especially one found in an urban setting is called a roof garden. Often there is a misconception in India between roof gardening and terrace garden. In many publications, the gardening on the roof is often termed as terrace gardening which is not strictly correct according to the British concept. In modern times, individual homes with a compound and a lawn are becoming rare in cities and towns and skyscrapers are replacing such homes. As a result, the private home gardens are vanishing and the only places left for gardening are the roofs of houses. A spacious well planned roof garden can be a place of joy and recreation. In bigger cities of India, many of the large hotels and public buildings are developing this type of gardens. Types of roof garden Based on the amount of maintenance required, the depth of soil and the types of plants the area will support, roof gardens are classified into three basic types namely, extensive living roofs, semi-extensive living roofs and Intensive living roofs. Extensive living roofs range from as little as 2.5 to 12.5 cm in soil depth. Semi-extensive living roofs have deeper soils and can therefore support a greater number and wider variety of plants, making them more decorative. However, their depth makes them heavy so they require a strong structure to support them. They can combine the relatively low maintenance of extensive roofs with a more aesthetic appearance. Intensive living roofs require a minimum of one foot of soil depth to create a more traditional roof garden, with large trees, shrubs and other manicured landscapes. They require intensive maintenance. Besides the above three types, other types of roof garden as detailed below are also being designed in recent days. Communal roof gardens: Green roofs can slope down to ground level, to make them accessible to pedestrians. This roof design is used for a spa hotel - an unusually protected environment. It could be used for campus-type environments (e.g. business parks and universities). Public roof parks: A green bridge can be used to join green roofs on separate buildings, thus creating a continuous public or private green space at roof level. This green space planning idea is described elsewhere as a skyway . Nature conservation roofs: It is often more appropriate to use vegetated roofs as wildlife habitats than as amenity green roofs for people. Private roof gardens: Roofs designed as living space have been made since ancient times. Unlike the roof garden types described above, private roof gardens benefit from (1) a surrounding wall, at least to waist height, for safety (2) an overhead shelter, or pergola, to provide spatial security and shade when required. Design and style A roof garden needs careful planning and designing. The essential requirements of a roof garden are detailed below. Waterproof layer - The base layer which is added to the existing surface. Roof membrane - Waterproofing layers, such as asphalt and bitumen, are very susceptible to damage from plant roots and any root penetration may lead to leaks. A pond liner or butyl lining or 300 micron damp-proof polythene should be laid over the waterproof. Filter sheet - This sheet allows moisture to drain off from the roof but retains fine materials. Drainage layer - This helps to retain moisture while allowing excess water to drain away. Commercial systems store water and are made of plastic or geotextile materials. Soils and substrates - The top layer. The growing medium should be light weight and free draining yet of a material that retains moisture. Planting and care Plants for roof gardening
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Last modified: Monday, 30 April 2012, 4:21 AM