# Implementing Circular Economy Strategies in Buildings--From Theory to Practice
## 7 Real-Life CE Implementation and Case-Studies  
This section presents some success stories of CE implementation in buildings to provides concrete examples of current worldwide CE practices. One of the first projects to adopt CE strategies is the project Circular Building in London developed by Arup, which was driven by the challenge of applying CE principles to the built environment [85]. The building's design was inspired by the Brand's 6S model consisting of site, structure, skin, services, space plan, and stuff. For the structure, reclaimed steel was used as a material that can be reusable after deconstructing the prototype and put back into the loop. The project designers tried to put together a structure with simple and accessible bolts that will not hinder disassembly and embrace flexibility and adaptability. Regarding the building's skin, engineers used a softwood that has the needed durability to sustain different use-cycles. All the products involved in the building's layers were sustainably sourced, and most of them contain recovered materials and are eligible for reuse or recycling at their end-of-life. These materials are healthy both to humans and the environment and have a low embodied carbon and energy. The circular building was equipped with sensors to generate valuabledata to control and adjust the indoor environment quality, namely lighting, temperature, and air quality to measure critical parameters. The first building project to rely on MP was the Brummen Town Hall [86]. The building was designed for future disassembly over a historic structure from the 19 th century building restored beforehand. The materials used are in line with the CE principles and can be further dismantled to be relocated and used into a new structure. As the building was designed for a service life of 20 years, the materials passport plays a crucial role in this project, namely, to keep track of involved materials and components to facilitate their reuse. Likewise, the renovation of the headquarters of the energy grid company Alliander, located in Duiven, The Netherlands, relied on MP to store valuable information regarding their origin and their further reuse [51,86]. Additionally, the building is energy positive, which means that it generates more energy than it requires. It has solar panels and underground water for thermal storage. The project used a minimum quantity of raw materials and used recycled wood and steel. Another example of materials reuse is the Quay Quarter Tower redesign located in Sydney, Australia, by reusing an existing structure. Half of the building resources are reclaimed from an existing structure, which substantially decreased the associated time, costs, and environmental impacts. Several case-studies across the globe attempted to concretize CE principles and provide real-life examples of how the construction industry can apply the paradigm shift. However, numerous challenges were noticed along the way. For instance, selecting the right building materials and components proved to be crucial for designers to embed circularity along the value chain [69,86]. In spite of the recent CE-related studies at the building level, intensive research is needed to accurately quantify the environmental, economic, and social benefits of applying CE in these entities. Considering an office building as a case-study, [PERSON] et al. [64] used a simplified allocation method to measure environmental impacts of disassembly and concluded that several parameters greatly influenced the findings such as the type of materials used, the reuse cycles, and building's service life. Similarly, [PERSON] el al. [18] assessed and compared the environmental impacts of different structural composite floor systems and found out that one that was designed for disassembly was identified as the most environmentally friendly compared to the conventional scenario. These positive results have been further supported by [PERSON] et al.