Designing for the Deconstruction Process
The construction and demolition industry is responsible for about a third of the waste generated in the UK. Reusing building elements in new construction, after the initial development has become obsolete can assist in diverting waste from landfill and can result in lower overall CO2 emissions associated with the new construction, thus helping to meet the government’s CO2 reduction commitments.
In this research the current barriers to the reuse of more structural materials are explored. It finds that there are barriers associated with the building design process, the demolition process, the logistics associated with reclaimed materials and the lack of demand for reclaimed materials.
It then proposes how the quantity of structural materials that are recoverable in a reusable condition could be increased. This is through encouraging design practices which facilitate careful deconstruction, thereby removing some of the barriers associated with the building design and demolition processes.
Design for deconstruction principles are identified through both a literature review and a survey of demolition contractors. It is also identified that there needs to be some additional incentive for these principles to be applied, as those benefiting from the increased recoverability of the materials are different from those paying
for the design in the first place.
Recognition in green building rating schemes is one way that those involved in the initial procurement of buildings can be encouraged to consider design choices that will have benefits for others in the future. Based on this, the research develops the detail of a design for deconstruction credit.
The credit includes the definition of a structure recoverability index (SRI) and a deconstruction plan. The SRI aims to measure how much of a structure is likely to be recoverable at end of life, with a higher weighting given to material recovered for reuse than recycling.
The deconstruction plan aims to both give enough information to allow the demolition contractors to be able to plan the deconstruction process and help promote the business case for deconstruction over demolition.
The credit proposed should hopefully be deemed to meet the requirements for an ‘approved innovation’ in the current BREEAM scheme and potentially form the basis for a full credit in future revisions of the scheme. In addition the work should provide guidance to those aiming to achieve credits on this subject in other schemes.
Designing for the construction process is only one aspect that needs to be tackled in order to maximise material recovery in the construction industry. This research does not address other aspects which are also important to increasing the amount of structural materials that are recoverable, in particular challenges associated with the logistics of stocking reclaimed materials. It is important that systems are established to facilitate the exchange of materials in the construction industry so that when the buildings we are currently constructing reach the end of their life they can be recovered effectively.
Reusability at end of life is only one aspect of the sustainability of a structure and may not always be the most appropriate strategy for a building. The client and design team should assess early on in the design process whether premature end of life is a risk for the building being commissioned, or if other issues such as optimisation for materials efficiency or future adaptability are more important.