Drivers of Housing Demolition Decision Making and the Impact on Timber Waste Management
The study investigates housing demolition and timber waste recovery – with the aim to identify ways of improving recovery. Using case studies the research focused on demolisher decision making, their onsite processes and the associated network of participants that influence timber recovery. From the data, a process model was developed that identifies and orders the drivers of demolition decision making. One aspect of the model identified the initiators of demolition and the waste created, including issues revolving around the demolition feedstock. Another aspect covers organisational business drivers and includes site safety, productivity, economies of scale, market value of waste and supply chain entrepreneurship. A third component deals with project specific drivers including the recurring cost versus income equation that impacts on the viability of project level decisions. The model includes a typology of the operational onsite response to the above drivers. Here, the deconstruction approach was found to provide high timber recovery mainly used where high-value timber waste was involved; the miscellaneous salvage approach provided some recovery of high and low-value timber; the crunch and dump approach provided low recovery or dumping at landfill and was used where low and no-value timber was involved. An expected increase in supply of these latter timber categories creates a significant need to increase the market value of currently low value timber groups. Designing for deconstruction is also posed as a long term strategy for this.