Green roofs - hygrothermal simulation of moisture and energy performance

Based on laboratory and field tests at the Fraunhofer IBP field test site a hygrothermal green roof model was developed, which allows to model the performance of extensive green roofs in hygrothermal simulation software. A comparison of the measured and simulated temperatures beneath the greenery shows, that the model well reproduces the real conditions. Also the moisture conditions in timber roof constructions as well as the heat flows through the roof assembly are compared once with the measured conditions from the field tests and once with the new simulation model. Main focus of the model is the evaluation of the moisture performance of roof assemblies which is of special importance in case of moisture sensitive timber roofs. But also a prediction of the energetic behaviour and the cooling effects of the roof as well as an evaluation of the comfort conditions in the room beneath the green roof becomes possible and is shown exemplarily for the warm Mediterranean climate of the South Croatian city Split in comparison to flat roof with a white and a black roof surface.