Roof planting is nothing new: The famous Hanging Gardens of Babylon existed more than two thousand years ago. For hundreds of years, "green roofs" have been protecting buildings in the North of Europe against cold and wind while sheltering more southerly constructions from the heat of summer. Reliable roof sealing techniques coupled with well-priced substrate, drainage and insulating layers using Liadrain® have brought about considerable improvements in today's constructions, including a number of economic and ecological advantages.
Various systems using a Liadrain® substrate layer are available for extensive roof planting: one of these uses waterproof roofing concrete with no sealing sheet while another comprises a sealing layer. In this latter system, the roofing concrete is covered by a cemented layer of Liapor 4/8 mm which acts as a gradient and water vapour compensation layer incorporating a thermal insulation and ventilation function. This is accompanied by a root-proof sealing layer, a protective layer made, for example, of polyester fleece, and the Liadrain® substrate layer.
Extensive roof landscaping with Liadrain® is suitable for undemanding, low-growing ground cover using lawn substitutes such as sedum, moss or herbs. In the case of growth heights of 5 to 15 centimetres, a construction height of 8 to 12 centimetres is required and leads to a unit load of 0.6 t 0.9 kN/m². More demanding covering plants involving a higher topsoil water content require a construction height of 12 to 16 centimetres to cater for growth heights of up to 20 centimetres. In this case, the unit load increases to 1.2 kN/m².