Assessment of sustainability aspects when making pre-renovation decisions

Sammanfattning: A considerable amount of Europe’s building stock needs to be renovated. The most common reasons for carrying out renovations are acute technical issues or the expiring life span of a building or its components. Other common reason for building owners to carry out renovations in their building stock are high costs for maintenance and operation, and a high energy demand. Furthermore, the construction and real estate sector have been found to be among the greatest contributors to greenhouse gas emissions and energy use and to increase the incentive to renovate the European Union (EU) has a strategy that include the initiative “Renovation wave”. Approximately one third of all multi-family buildings in Sweden need to be renovated, especially multi-family buildings and schools constructed during the record years. Buildings can be seen as our most complex and durable consumer goods. Subsequently, in renovation projects, decision-making is also a complex matter and during the initial evaluation phase of a renovation project it has been seen that there is a lack of time, knowledge, information and tools to make decisions. The hypothesis in this thesis is “Building owners do not, in a systematic way, take into account and manage sustainability aspects in pre-renovation decisions”. The hypothesis was investigated by seven studies that have been carried out by using different methods, such as case studies, surveys, action research, documentation, and literature studies as well as life cycle assessments including scenario and sensitivity assessments.First a literature review on different renovation strategies that could support in including sustainable aspects systematically within the areas of economy, environment and social was conducted. The review showed that there are several strategies to support decisions of sustainability aspects in a renovation process. The problem does not seem to be lack of strategies but rather the implementation of existing strategies as well as continuous development of the strategies.Therefore, the building owners´ consideration and implementation of a number of sustainability aspects were further investigated. Within the category ‘economic aspects’, the focus was on energy costs and profitability. For the category of environmental aspect, focus was on energy use and climate change potential. Social aspects mainly included indoor environmental quality, but also other social aspects that came to light during the performed case study.When analysing previous renovation projects, it was evident that information from earlier renovations was limited. It seems, in these cases, that there is a lack of systematic documentation about how the information before a renovation was generated. Information seems to be missing or linked to an individual person. Systematic feedback and exchange of experience is therefore vulnerable as people change jobs or retire which complicates the transfer of knowledge to future renovation projects. When following the early phase of a school renovation it was evident how important earlier experiences were. The discussions that were carried out in the early planning phase were, to a great extent, due to the earlier experiences from the included participants.Finally, climate change potential for energy renovation measures was assessed. The results showed that if the energy mix is assumed to change in the future, with less fossil fuel and more renewable sources for electricity, the assessment of energy renovation measures is important to perform. The minimum and maximum variation in materials´ climate change potential show that assessment of different choices of materials should always be carried out before a renovation measure is performed.Based on the results from the performed studies, the hypothesis in this thesis is partly proven. Building owners have started to manage and treat several sustainability aspects in pre-renovation decisions. Methods to consider sustainable aspect of energy use was found to be much more developed than methods to consider aspect such as climate change potential that is in the beginning of the development. A variation of social aspects is treated in different renovation projects but more depending on what is considered to be of importance, than with a systematic approach. However, sustainability aspects are not yet managed in a systematic way. Even though there are several renovation strategies and frameworks with methods and tools available, these are not yet implemented and used in a systematic way by building owners. Furthermore, common for all aspects, there is a need for building owners to adapt the renovation strategies aspect to the conditions of their company and the specific renovation project.