*3.2. Building Stakeholders' Needs for Design Support Tools*

Having categorised the design tools, the question is whether or not they answer the needs of the building designers and advising engineers who are trying to integrate circular principles in their practice. Therefore, the needs that are expressed by our focus group are placed in the developed framework, where they are categorised per design stage and per circular design tool category (Figure 3).

For a consistent categorisation of the expressed needs, the specific role of architects and advising engineers in Flanders was taken into account. That role is broader than "designing plans" and, thus, different from some other regions. Architects and advising engineers in Flanders are a pivotal figure between the client and contractors, they are obliged to supervise the construction works and remain responsible 10 years after completion of the building. Moreover, regulations require architects to implement increasingly more diverse knowledge on specific themes such as energy and water use or building safety and health. They are also expected to have insight into the society, whereby they have the ability to respond to future needs of building users and to be informed of the latest (innovative) building trends and solutions. The emergence of the circular economy in construction is consequently considered as "yet another constraint" by multiple designers [72].


**Figure 3.** Framework 2: Categorisation of the building designers' and advising engineers' needs for tools for circular building per design phase and per design tool category (green bars). Related interviews are indicated as: (1) researcher sustainable buildings; (2) facade contractor/designer; (3) architect (engineering office); (4) sustainability engineer; (5) architects; (6) architect; (7) architect.

From the interviews and the filled-out framework, a series of findings becomes apparent. They can be discussed per design tool category:


more informed. Conversely, the disadvantages include the risk that actors lose their criticality on materials and the difficulty to keep the overviews up to date in this transitioning sector.


### **4. Discussion**

Comparing the available tools (see Section 3.1) and the building actors' needs (see Section 3.2) yields three possible outcomes: (1) there is a need but a corresponding tool is not (yet) available; (2) there is a need and a tool is available; and (3) there is no need, however, a tool is available. Each of these three situations is discussed hereunder and can be related to one or more tool (sub)categories and their role in the design process. Those situations are subsequently put in contrast with ongoing research tracks and developments.

### *4.1. Comparing the Available Tools and the Building Actors' Needs*

First, from the interviews it can be concluded that there is an important need for practical examples and best practices. The current platforms and learning networks do not seem sufficient to bring those examples and best practices together and share them further. Although platforms enable information exchange and direct interactions [26], each has its flaws with regard to a scale-up of circular building. Some for example, accept only a small "expert" group, require a financial contribution, or lack a coherent structure [76]. Further, interviewees expressed an absence of practical examples with sufficient technical information [78], learned lessons, etc. Others repeat their demand for cases that did tackle and report on juridical challenges of circular building in today's context [75,76,79]. Moreover, platforms and learning networks do not, or only in one direction, facilitate matchmaking between professional partners interested in circular building. The coverage, usefulness and effect of platforms as they are today must therefore be questioned.

Second, during the interviews, needs were identified while tools are already available. Possible explanations for tools not being used are: marketing strategies are lacking, they are not satisfying the users' expectations or they are too complex, time-consuming, and expensive [80]. The ease of use, next to

the associated costs, is one of the most important criteria when selecting design supporting tools [20]. User-friendliness of tools could include, for instance, compatibility with other software and compliance with standards and regulations [20]. This results in the dismissal of some tools, the remaining need for such tools and the oversupply of certain other tools. For example, this research identifies a need from practitioners for tools to calculate a circularity score, while there are already tools available that could (partly) do that. However, not all interviewees agree on the necessity and relevance of circularity scoring. Various possible disadvantages were mentioned: first, the term "circularity" could be greenwashed, i.e., a scoring tool that does not lead to more circular outcomes and falsely promotes its efforts (strategies, method and goals) as environmentally friendly or circular [81]. This means that a scoring tool can, for instance, focus on achieving certain circularity goals, such as using Building Information Modeling (BIM) to manage your project or designing the building elements in such a way that they could be reused after the building's lifespan, but does not necessarily serve the general goal of lowering the environmental footprint of the constructing sector. For this reason, vigilance and a critical eye are important to ensure a relevant implementation. That the terms "circularity" and "circular economy" are ambiguous and the broader socio-economic implications of a CE are often side-stepped [82] is extensively described in the growing literature that is analysing the CE and its problematic relationship with perceptions, policy and consumption such as by Hobson and Lynch [82], Gregson et al. [83], Torelli et al. [84] and Testa et al. [85]. Second, each project is different which makes it difficult to quantitatively measure indicators and to compare them as such. Until today, there is no agreed framework for circular building benchmarking. This means that the results generated by circularity score tools might differ significantly from each other, which could lead to confusion or misinterpretation. Developers of circularity score tools should thus be careful which indicators they measure and how they can avoid greenwashing and stimulate circular building. The different opinions on circularity scoring tools show that the needs are dependent per user and their expertise. However, in order to make any further conclusions, more research is needed on this topic.

Third, there is an oversupply of certain tools that are developed with the same purpose, for the same design phase, for the same design aspect and usually also for the same target group. On the one hand, this oversupply is represented by the eight subcategories of tools in Figure 3 and, on the other, by the red "Not Needed" bars in Figure 3. For example, the subcategory "Design Principle Tools" contains four tools available in Flanders. Two interviewees expressed that there was no need for more such tools that elaborate on theoretical principles of circular design. When developing a new tool concerning circular design principles, the added value of that tool should therefore be questioned and doing a focused survey on the remaining needs for information and guidance in design principles of circular construction is thus recommended.
