Theoretical Analysis and Comparison of the Thermal Performance, Construction Costs, and Maintenance Complexity between a Conventional and an Intensive Green Roof

In this paper, a comparison between a conventional flat roof and an intensive green roof was made. Emphasis was on thermal conductivity of individual layers, the calculation of thermal resistance, and calculation of the thermal transmittance coefficient through both roof variants. The calculations for the two analysed roof variants were made for a building located in the town of Rijeka on the Adriatic coast. This paper also presents the construction technology comparison of the analysed roof variants. The construction cost was also analysed for both roof variants together with time needed for the execution of variant solutions. Finally, maintenance plans for both roof variants were presented in this paper. The results show that the construction costs of an intensive green roof are higher than the construction costs of a conventional flat roof and that the maintenance of the intensive green roof is more complex. On the other hand, the results of the analysis also show that constructing a green roof will result in more energy savings in the long term than in the case of constructing a conventional flat roof. In addition, there are several other benefits that go in favour of constructing an intensive green roof. Most prominent among those benefits are environmental and social benefits.