Does design-for-deconstruction increase upfront embodied carbon? Life cycle assessment of a deconstructable building

The construction industry produces 140 million tonnes of waste and consumes 400 million tonnes of raw materials annually within the UK. The aim of a circular economy is to retain materials in the value chain, thus reducing waste production, raw material extraction and their associated environmental impacts. Design-for- Deconstruction (DfD) aims to facilitate the recovery and reuse of a building’s component parts. It is thus a critical part of achieving a circular economy. However, there is a risk that DfD increases upfront embodied carbon, for example if higher carbon processes or extra materials are required. The long-term environmental benefits of DfD are also challenging to quantify as they occur at end-of-life, which possesses the greatest uncertainty in a building’s life cycle. Therefore, a life cycle assessment (LCA) of an educational building in Swansea, UK has been conducted to investigate how DfD strategies influence a building’s upfront embodied impacts. The case study building has been designed to be deconstructed in 2026. The Global Warming Potential (GWP100) is reported for: cradle-to-gate [A1-A3]; transportation [A4]; construction [A5]; replacement [B4]; and, operational energy use [B6]. When assessed over a 60-year period, A1-A5 accounts for 60% of the building’s total GWP100, while B4 accounts for 25% and B6 for 15%. For the case study building, DfD strategies have been implemented while keeping cradle-to-gate impacts 25% below current ‘business-as-usual’ target values for the UK. The case study demonstrates that, when implemented effectively, DfD strategies can produce net- reductions in whole-life GWP100 impacts while providing end-of-life