LCC and LCA of dynamic construction in the context of social housing

Continuously changing household needs and evolving building standards require a frequent upgrade and renovation of our existing residential building stock. A lack of adaptability of buildings, however, often leads to destructive interventions, resulting in financial and environmental impacts. The goal of this paper is to contribute to the search for new design concepts enabling easier and more cost-effective upgrade and renovation of buildings. It should moreover contribute in achieving a lower life cycle environmental impact. A more dynamic design is evaluated in the specific context of a social housing project in Mechelen (Belgium). In this context, building elements with reversible detailing techniques facilitating disassembly and component reuse are compared to more traditional static elements. The benefits and drawbacks are assessed at the building level using a life cycle approach of economic and environmental aspects, i.e. a Life Cycle Costing (LCC) and Life Cycle Assessment (LCA). Different renovation scenarios are simulated focussing on the internal restructuring of the housing units. Two alternatives were investigated: dynamic assemblies of all internal walls versus dynamic assemblies of only those internal walls which are expected to change more frequently. The analysis revealed that the building concept and layout are important for making more dynamic design beneficial or not. Building layouts which provide opportunities for change generally require limited constructive adaptations during the building life span. Application of dynamic assemblies to only those walls which are assumed to be changed in future is then preferred over an application to all internal walls. This could be called a 'selective' approach. Such a 'selective' approach can result in life cycle environmental benefits while the additional financial costs remain limited.