| dc.description.abstract | Abstract
The scope of this study is to assess how different building materials affect building renovation in terms of circularity and environmental impacts. Renovation of existing buildings has been identified as a key strategy for reducing environmental impacts associated with building construction. At the same time, it maximizes circularity. The EU and Norway have set ambitious goals to reduce carbon emissions by the year 2030. There is special attention on reducing life cycle emissions in building sector. Information on the current composition of buildings is typically lacking, including reuse and transformation potential. This information is only available at the time of demolition when it is too late to plan and design for an efficient reuse process. Therefore, this thesis aims to increase the knowledge about the reuse potential of currently used materials and construction alternatives with secondary materials.
To determine the emissions reduction potential of circular strategies combined with the use of biogenic materials in comparison to standard construction methods, a renovation scenario was analyzed using Life Cycle Assessment (LCA). The renovation scenario (for the IKEA, Leangen-Trondheim) included a part of an on-going proposal at IKEA, a concept design for display area, storage and adding a new extension to the existing building. A circularity calculator in OneClick LCA was used to measure the circularity of the design. The design methodology of this thesis focuses making a circular design by reusing what is already on the site, reuse material from other places around Trondheim and then use new materials and design methods that make the design more adaptable and easier to dismantle in the future.
The scenario also considers short use periods of materials and components, as their turnover can be fast, especially in retail stores, where displays are exchanged often. The study shows that for such scenarios, emissions are almost 2.5 times higher (16 M kg CO2e) than if the materials were in use for a longer period (6 M kg CO2e). Overall, a combined strategy between using materials for longer periods, reusing materials and components on-site, and choosing biogenic materials for added components in one circular renovation process can save 6.3 M kg CO2e emissions over the lifetime of the building compared to the standard scenario.
The main uncertainties of this study lie in the definition of system boundaries of the building renovation. The end-of-life stages vary significantly and some of the studies exclude it from the scope of renovation scenarios. The end-of-life stage was taken into consideration based on the literature and assumptions.
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One of the major results is the material catalogue which provides a systematic template as a basis for circular renovation. It was developed using the case study example but could be populated for other IKEA buildings and used by other clients as well. This could be developed into a database management system for existing and new buildings which help to create a circular material inventory.
Key words: Renovation, Circular economy, Life Cycle Assessment, Building materials, Reuse, Recycle, End-of-life | |