Building information modeling (BIM) and life cycle assessment (LCA) are two methods that can be helpful when designing buildings with lower environmental impacts. One of the most significant examples of environmental impact assessments in construction is green building certification. Certified buildings have improved performance and greater asset value. In this study, four certification systems were investigated for their potential interconnections with BIM and LCA. The main tasks were (1) to review a BIM-based workflow, (2) assess its usage as an input for the LCA within green certifications, and (3) provide suggestions for developing building models. Building models can be helpful during the design process, but the best results are expected when the specifically described steps are followed. These suggestions aim at improving building models in terms of their usage for green building certifications and particularly for LCA. All the investigated results were clarified and adjusted using a model of a recently finished building in Zug. As reference tools, One Click LCA and a manual process were selected. The outcomes were aligned with those of other studies and confirmed the necessity of good data and management quality for building projects.

Energy retrofitting of existing building stock has significant potential for the reduction of energy consumption and greenhouse gas emissions. Roughly half of the CO₂ emissions from Czech building stock are estimated to be allocated to residential buildings. Approximately one-third of the Czech residential building stock have already been retrofitted, but retrofitting mostly takes place in large cities due to greater income. A favourable concept for the mass retrofitting of residential building stock, affordable even in low-income regions, was of interest. For a reference building, multi-criteria assessment of numerous retrofitting measures was performed. The calculation involved different building elements, materials, solutions, and energy-efficiency levels in combination with various heating systems. The assessment comprised environmental impact, represented by operational and embodied primary energy consumption and greenhouse gas emissions, and investment and operational costs using the annuity method. Analysis resulted in the identification of favourable retrofitting measures and showed that complex building retrofitting is advantageous from both a cost and an environmental point of view. The environmental burden could be decreased by approximately 10–30% even without photovoltaic installation, and costs per year could be decreased by around 40%.

Life cycle assessment (LCA) has become an important part of building design optimization. Design studios need tools that make the LCA of buildings faster and simple, and provide results that allow comparison between variants. The objective of this study was to show the possibility of LCA data integration into the existing building design tool, the DEK Building Library, which is already widely used in the Czech Republic, by connecting it to 1200 items of the largest Czech cost-estimating database, and the application of this connection into building information modeling (BIM) tools. This process also included the large-scale adaptation of 160 relevant LCA data. The main result was obtained using EnviBIM, a freely accessible BIM plugin, as well as a web interface that allows users to receive cradle-to-gate environmental impacts of DEK Building Library elements. Additionally, a semi-automated algorithms system for different groups of building materials and elements named EnviDataGenerator was developed in MS Excel, which enables the consistent linking of LCA data to the cost-estimating database items. This allows EnviBIM extensions and upgrades. The EnviBIM module was validated using case studies of three buildings modeled in ArchiCAD and REVIT. The difference in results compared to the manual calculation was 3.1% to 10.9%, which was considered a success.

The building industry consumes a large amount of primary raw materials and also contributes significantly to the production of waste. Applying circular principles in this field to reduce resource consumption and waste production has been investigated in several projects considering the reuse or recycling of construction and demolition waste. However, consumption of primary raw materials can also be reduced by re-targetting waste from different industries and municipal waste to produce new construction products. Thus, opportunities for the recycling of industrial and municipal waste were investigated in this project. The main output is the catalogue, which provides an overview of products with recycled content and secondary materials with the potential to be used in the construction industry such as blast furnace slag, ash, and energy by-products. Also, it contains a list of valid requirements for the use of recycled materials under specific conditions of the Czech Republic. In addition, examples of good practice are presented to break the existing behavioral barriers to the use of secondary raw materials in the Czech construction industry. This contribution summarizes the findings in the field of industrial and municipal waste recycling and its further use as secondary raw materials in the construction industry.