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Notes:
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Today, green roofs are a building system which provides interesting benefits over traditional roof solutions.
The most important advantages are the reduction of surface runoff in cities, improvement of the
urban climate, biodiversity support, improvement of the durability of roofing materials, and, especially,
energy savings. This paper has the aim of studying the performance of green roofs as a passive system for
energy savings, within a wider objective of seeking constructive solutions suitable for sustainable and
environmentally friendly architecture. This idea is tested at an experimental installation available at
the University of Lleida, with several cubicles testing the energy performance of different construction
solutions. This work raises the possibility of using recycled rubber from tires as a drainage layer in green
roofs, substituting the porous stone materials currently used (such as expanded clay, expanded shale,
pumice, and natural puzolana). This solution would reduce the consumption of these natural materials,
which also require large amounts of energy in its transformation process to obtain their properties. Moreover
it would provide a solution to the problem of waste rubber from the tires, known as rubber crumbs.
Since the purpose of the drainage layer is the optimum balance between air and water in the green roof
system, first the ability for draining of recycled rubber granules was studied and was compared with the
offered by stone materials. The new solution using rubber crumbs is also studied to test if it would keep
the same insulating properties that the green roof with stone materials presented in previous studies.
Early results show that this extensive green roof system can be a good passive energy savings tool in Continental
Mediterranean climate in summer, and that rubber crumbs can be an interesting substitute for
stone materials used as drainage layer in this type of green roofs.
This work was partially funded by the Fundación Mapfre (call 2009), the Spanish Government (ENE2008-06687-C02-01/CON) and the European Union (COST Action COST TU0802), in collaboration with the companies Gestión Medioambiental de Neumáticos S.L (Pológon Industrial Piverd s/n, Maials.) and Soprema. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2009 SGR 534). |
