In recent years, the Netherlands has witnessed a growing housing shortage, prompting an ambitious plan by the government to address the demand through increased construction of new housing until 2050. Moreover, as part of environmental commitments, new dwellings and existing housing stock must align with current energy performance standards and the circular goals by the same target year. Hence, exploring alternative ways of increasing housing capacity
is crucial to meet the growing demand while ensuring alignment with the environmental requirements.
This research examines timber top-up’s structural feasibility and circular potential to expand existing dwellings’ area as an alternative to a common practice: deconstruct followed by building new. Furthermore, provide an approach to the circular principle of Reuse to transition existing Reinforce Concrete structure in dwellings from a linear to a circular economy. The present thesis consists of a literature review analysis of the potential of mass timber to top up, followed by the analysis of two local case studies that implemented this strategy. Then a dwelling with a relevant RC structure typology in the city of Deflt is selected as a case study to propose a conceptual modular structural design for a Timber Top-up system.
Three scenarios with different area capacities are proposed and tested to analyze the structural feasibility based on four structurally defined criteria (Reaction in the foundations, Utilization and reactions of the main RC structural components & timber components & deflection limit), followed by the analysis of the CO2 footprint of the Top-up scenarios. The tests are performed with the parametric structural analysis plugin Karamaba 3d, followed by the use of the software Granta Edupack with its feature Ecoaduti tool. The result showed that
topping up using mass timber is an effective strategy to reduce the Upfront embodied carbon of existing RC structures while increasing the area capacity of the building.