Due to the increasing demand of habitable space in the city of Vienna and generally in central Europe, and the restrictions limiting building in the central area, the refurbishment of the existing building stock has played an important role for instance by performing rooftop extensions in the building environments development of the 21st century. In this context, the great potential of wood constructions solutions is under scrutiny. In principle, wood constructions are considered to be fast-assembly solutions as well as eco-friendly, due to the positive eco-balance of wood. Moreover, the favorable building physics characteristics of wood and wood-based materials enable high-energy efficient performance of building elements and constructions. In this master thesis, this will be tested and further developed for an attic extension, in order to cover the need for a fast-assembly and environmental friendly solutions, and to promote energy efficient performance of building elements. In detail, this master thesis focuses on an integral assessment of different rooftop solutions for a representative reference building in Vienna. This study aims to evaluate and compare the performance of six roof alternatives in terms of thermal behavior, ecological impact, and cost-time efforts. Each category has been assessed by the implementation of different methods such as numerical building simulation and building standards procedures. Moreover, reference works were used for the realization of appropriate estimations for the cost calculation. Regarding the results of the study, the following can be stated: by implementing construction details with similar thermal characteristics, the thermal performance in winter of the attic space is not significantly influenced by the type of construction. However, thermal comfort is important to be considered in the summer period. In cases where the building design is not appropriate and given the prevailing Viennese climatic conditions , an attic spaces indoor temperature can reach 37C. A control of the summer overheating is essential in this type of renovations. The results have shown that by implementing massive wood solutions, discomfort hours can be significantly reduced in comparison to other solutions. While performing a “cradle-to-gate” ecological evaluation, all details have shown an absolute low ecological footprint. However, the implementation of certain wood assemblies can reduce 50% the relative ecological impact values in comparison to other solutions. The main difference between the details can be seen (therefore) in terms of cost evaluation. Based on the findings of this works, it can be stated that the main challenges of the integral assessment of rooftop extension are the implementation and availability of different software assessment tools, the feasibility study of building elements and an accurate building design and documentation.