The purpose of this thesis is to determine which structural assembly of the roof is the most cost-effective, given the service life, materials used and energy efficiency of their design. The analysis is based on seven scenarios, divided into three groups according to similarity, which include the renovation of the roof of a representative Slovenian residential house. The analyzed construction assemblies meet all the requirements of the Regulations on the efficient use of energy in buildings. Scenarios include both minimal renovations as well as scenarios with a more comprehensive renovation and replacement of the entire load-bearing structure of the roof. Using so-called standard and above-standard materials and the diverse quality of the built-in elements, the scenarios are an approximation of the diversity that occurs in practice. Each individual scenario is considered through the energy model of the house, made in the KI energy program, to which data on the materials - building blocks of each part of the building were added. In the OneClickLCA program, the life costs of the building for a period of 40 years were analyzed on the basis of the calculation of energy efficiency and estimated investment costs. The mutual comparison of scenarios, through their lifetime, is evident from the time-dependent cost analysis. It has been established that the use of so-called above-standard materials and quality elements pays off in the long run, and that high entrance costs do not mean higher costs at the end of the building's lifespan. The obtained research results, due to the consideration of the phase of replacement of worn-out materials, realistically show high mutual differences and deviations. Despite the obtained results, it is concluded that the best-case scenario depends on the purpose of the property and the financial capabilities of its investor.