The Analysis of different Thermal Insulation Thicknesses in the Systems of Inverted and Combined Flat Roofs

The aim of the project of one-dwelling building is to conduct a study of thermal flux and\ud diffusion of water vapour through a part of the building cladding. By means of a computer\ud program, examples of structural complexes of flat roofs of two types are made – inverted flat\ud roof and combined flat roof. By complying to the criteria of allowed thermal transmittance of\ud flat roofs as are written in the PURES 2010 (Pravilnik o učinkoviti rabi energije v stavbah),\ud including the corresponding technical directive and the treatment of calculation method of the\ud thermal transmittance of building components set by the ISO 6946 standard, the effect of\ud different ratios of thermal insulation between the two types of flat roof on the change of\ud thermal flux and the corresponding needed change of the thermal insulation thickness of the\ud material in the system of the roofs in consideration is studied. An appendix on inverted flat\ud roofs is taken into account in the first part of the study of the thermal flux through structural\ud complexes, a correction stated in the ISO 6946 standard. The latter contains a correction on\ud the system’s thermal transmittance in regard to the additional heat loss due to the water\ud percolation through the juncture of thermal insulation layer. Additionally, an appeal for the\ud correction of the thermal conductivity in regard to the change of thermal conductivity of the\ud thermal insulation is made in the aforementioned appendix, to integrate the possible increase\ud of the moisture content due to the diffusion of water vapour. This subject is represented in\ud the second part of the study