Extensive roof garden as a thermal insulator

Abstract

Extensive green roofs are established with thin layers of substrate exerting only small load to the roof. The construction of such a roof is relatively simple, low cost demanding, and, on the other hand, it is able to improve not only the ecological value of the concerned building but also the overall value of its surroundings. One of the requirements an extensive green roof is able to comply with is thermal insulation of the roof. The aim of our research was to find the extent of energy savings in case of a model green roof in climatic conditions of the Nitra town. The roof was built with standard materials with heat transmission coefficients refereed by the manufacturer. At the same time we evaluated, using the TEVLAKO software (software for heating systems and thermal protection of buildings), energy savings and losses corresponding to reduced thickness of thermo-insulating materials used for construction of the studied model extensive green roof. We obtained the following results: 1. An extensive green roof can represent lower costs thanks to reduction of the necessary thermo-insulation layer. 2. In summer, an extensive green roof can represent savings in energy necessary for cooling air in rooms situated immediately under the roof, because green roofs reduce the penetration of heat from solar radiation and can lower the inside temperature under the roof by 5-6°C.