Drivers, barriers and enablers: construction sector views on vertical extensions

Buildings and construction are responsible for 38% of global greenhouse gas (GHG) emissions, making decarbonisation of the construction sector essential in combatting climate change. Limiting resource consumption and waste generation by transitioning to a circular economy (CE) is key to reducing emissions. The adaptive reuse of existing buildings, such as through their vertical extension, represents one of the most effective ways in which this can be done. Despite this, and although existing work has been completed in surrounding contexts, understanding of factors influencing the uptake of vertical extensions remains limited. Through a survey and follow-up interviews, this paper investigates construction sector professionals’ current awareness, uptake and experience of vertical extensions, as well as the key drivers, barriers and enablers affecting implementation. Economic factors are revealed to be the primary driver for extension projects, though case-by-case variability results in commercial risk in some instances. Other barriers include difficulty appraising existing structures, resistance within the construction sector and unfavourable tax regimes. Mandatory whole-life carbon assessments and adjustment of tax regimes are recommended to increase uptake of vertical extensions, as well as enhanced education of engineers and greater consideration of CE amongst stakeholders.