Re-use of structural elements. Environmentally efficient recovery of building components
The building element re-use practices differ with the size and complexity of the reclaimed parts. The smaller ones such as bricks, wooden boards and steel sections tend to be re-used in a more organized way, collected in the salvage yards and re-sold as basic materials in the local community. On the other hand, larger and more complex structural systems have a higher value, but lower applicability, and therefore a different approach should be selected for their re-use.
Online marketing, component labelling and BIMs are the technologies that are feasible for increasing the efficiency of such components’ re-use. The special category is the whole building structure. Re-use of building components is generally one of the most environmentally friendly end-of-life scenarios of the building; provided that the durability of the components extends the life of the building and that there is a suitable application for it. Re-use benefits can nowadays be declared in a standardized way according to EN 15978.
Many environmental certification systems recognize re-use in their assessment process, however, the contribution of material and resource efficiency to the overall score is usually very low.
There are many other practical obstacles to the building components’ re-use that should be addressed. One is the lack of strength grading rules for materials in re-used elements. This means that re-usable load-bearing components are often forced to be applied to non-structural purpose unless they are thoroughly tested in certified laboratories. Another obstacle is the difficult of deconstruction of existing buildings. The extended time and high demands on manual labour usually increases the cost of the whole process. This can be partly improved by applying standardized deconstruction practices, proper staff training and using selected technologies for deconstruction.
However, the greatest impact on a building’s reusability is in its design stage. Therefore, we recommend addressing this issue in the planning of future steps towards resource efficiency.
The standardization process and the recent changes in the environmental certification systems indicate that the importance of life-cycle assessment of buildings and components will grow in the near future. However, there is a lack of reliable LCA data for the most critical stages in re-use such as deconstruction, sorting, quality check and re-distribution of materials and components. These gaps in lifecycle inventory databases have to be addressed in the future.