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We Test Green Roofs

02.08.2019

The University Centre for Energy-Efficient Buildings of the CTU carries out long-term testing of different types of vegetation roofs in its seat in Buštěhrad in cooperation with the Metrostav company. The aim is to assess various compositions of green roofs with regard to the reliability of their function, maintenance demands and other properties. The knowledge acquired can be a significant contribution to energy-efficient cooling of buildings and their surroundings during hot days.

The testing takes places on 24 test plots in total that were formed on the roof of the UCEEB building in Buštěhrad in June of 2018. The aim of the experiment is to provide as wide a spectrum of compositions of extensive green roofs and planted vegetation consisting of a mixture of drought resistant plants as possible. Extensive green roofs are characteristic by its low requirements on the height of the complex of layers. Different types of available substrates are tested. These are combined with a wide selection of drainage and hydro-accumulating layers in the plots. The vegetation of the roof test plots consists mostly of Sedum species and Sempervivums species (see the photograph below), the vegetation on the rest of  the plots consist of the mixture of herbs and festucas. Sedum carpets are tested, too.

All test plots are equipped with autonomous micro-climatic stations that measure the moisture and temperature of substrates. A weather station located on the green roof of the UCEEB building provides meteorological data (air temperature at 6 and 200 cm, air humidity, air pressure, wind direction and speed, energy balance between incoming and outgoing radiation) to evaluate the green roof performance. Scientists also observe and capture by a digital camera the changes in vegetation cover and presence of undesired weeds. Currently, processed data that were acquired during the first and second stage of the project from June till December of 2018 are available. The conclusions and the final evaluation of the experiments are planned for the end of 2021.

 

Vegetační střecha tvořená směsí suchomilných rostlin.