Adaptability in timber construction: Evaluating frameworks for flexible multistorey building systems and material-specific requirements

Abstract

As buildings face changing functional demands and increasing environmental requirements, timber, a renewable and versatile material, could support such adaptation. However, timber's capacity to support long-term transformation remains underexplored. Since multistorey timber buildings (MTBs) often face sustainability certification-including adaptability demands-and material-specific performance requirements, this adaptability gap carries great consequences. This paper aims to understand whether existing adaptability frameworks-predominantly designed for steel and concrete-can capture the specific requirements of timber construction, and how they might be adjusted to do so. We asses the suitability of quantitative adaptability frameworks for MTBs by analysing 28 adaptability indicators with an umbrella review, and applying two established frameworks-DGNB ECO2.1 and Adaptive Capacity DBGC BREEAM MAT7-to five representative timber building system cases. Results show systematic disparities between current criteria and MTB requirements: (1) frameworks lack consensus on significant parameters and target values-ceiling height, extendability and typical span recur- and are rarely validated with timber cases; (2) qualitative, design-driven adaptability is underrepresented, indicating a need for holistic assessment that integrates key physical, spatial and technical aspects; (3) MTB-specific properties-lateral stability, acoustic and fire performance, free floor area, logistics and profile differentiation-require explicit treatment; and (4) scenario-testing with material-specific requirements is needed to capture adaptability's full complexity. Moreover, metrics inherited from steel-concrete practice (preference for large spans and flat ceilings, penalties for load-bearing walls) can undervalue timber strategies such as modularity, lightweight logistics and permeable load-bearing walls. We outline a pathway towards materialinclusive Design for Adaptability for MTBs.