Design for Structural Adaptation in Timber Buildings: On Industry Potential for Implementation Towards Resource-Efficient Timber Structures

Licentiate thesis, 2024

Building service life extension has been identified as a key strategy for the construction sector’s transition to a circular economy. Yet, there is an increased awareness that business-as-usual buildings lack the adaptability needed to accommodate changed user needs or damages. As an approach to rectify this, the concept Design for Adaptation has gained traction within the field of building circularity research. The concept aims to slow down resource loops by creating buildings that accommodate physical changes, thereby facilitating service life extensions. While there are self-evident motivations to apply such strategies to non-renewable and carbon-intensive building materials, there are particular benefits of applying them to timber as well. Extending the use phase of timber products promotes resource efficiency and waste reduction, with the added benefit of prolonged carbon storage. The common concept of Design for Adaptation is, however, mainly concerned with non-structural building adaptations. If the load-bearing structure is damaged, or extensive conversions are needed, the building may face demolition still.
This thesis introduces the concept Design for Structural Adaptation (DfSA) and applies it to load-bearing timber structures. The subsequent research work described in this thesis is based on the assumption that an implementation of DfSA for timber would be beneficial from an environmental perspective, but perhaps not feasible from an industry perspective. Thus, there is a need to determine the industry potential to implement DfSA for timber. The future development of the concept should further be based on key enablers of an industry implementation, which have yet to be identified.
The thesis lays the foundation for the future development of the concept DfSA for timber buildings. The benefits and barriers to an implementation are investigated by conducting semi-structured interviews with industry stakeholders in Sweden and Australia. Subsequently, the actions needed to overcome the identified barriers are determined, resulting in a roadmap towards implementation. Lastly, the practical and economic implications of implementing the concept are investigated in a Swedish context. The process of adapting a structurally adaptable timber building is mapped, and important considerations to facilitate the process are identified. To investigate the long-term economic perspective, a cost-benefit analysis calculation model is developed. This model is then used to determine whether investing in a timber building’s adaptability is economically feasible, and how this economic feasibility can be increased.
The results show that there is currently a lack of direct economic benefits to motivate industry decision-makers to an implementation of DfSA for timber. However, the future development of the concept may create stakeholder incentives. To achieve this, the development should focus on cost-effective technical solutions, both from a structural engineering perspective and for building and material traceability. The solutions should further be well-documented and communicated, to increase the likelihood of implementing this strategy for resource-efficient timber structures.