Renovation Will Skyrocket in the Coming Decades and Can Result in Much Lower Emissions

Renovations generate around 50-75% fewer emissions than new construction.

In the coming decades, large numbers of existing buildings will require repairs and reparations. By 2030, there is expected to be a sharp increase in the number of concrete structures becoming overburdened and in need of building system repairs (such as structure and finishing) (Vilches, Garcia-Martinez and Sanchez-Montañes 2017). The value of the global concrete restoration market is set to increase at a compound annual growth rate of around 6 per cent by 2030, to reach nearly $26.4 million (Vilches Garcia-Martinez and Sanchez-Montañes 2017). This growth is projected to be greatest in North America, where many mid-century structures are experiencing premature deterioration due mainly to poor building quality, improper design and a failure to make timely repairs.
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Decisions at an early phase to use less materials by re-using buildings or their components – especially retaining foundations and structural systems – results in avoided demolition and waste, and less embodied carbon. Renovating existing buildings generates around 50-75 per cent fewer greenhouse gas emissions than new construction, because it typically involves re-using the building structure and envelope, which make up most of a building’s carbon-intensive processes and materials (e.g., concrete, brick, steel and aluminium) (Strain 2017).

The selection of materials and systems is critical towards creating a low-carbon building. Engineered bio-based materials, such as cross-laminated timber and bamboo, offer the potential to replace concrete and steel components, particularly for the widespread re-purposing of older commercial buildings, where new floors are added to supplement housing units. Swapping a concrete-based exterior wall system with a bio-based structure such as timber or bamboo could greatly reduce both the upfront embodied carbon and the ongoing operational emissions associated with heating and cooling systems. Carbon emissions from renovations can be further reduced by avoiding the replacement of high-carbon materials such as carpeting and ceiling tiles, and instead simply polishing the sub-flooring and ceiling structure as the interior finish.

Repurposing waste materials into new functions on-site or for nearby use can save carbon.

Extending the lifespans of existing buildings and re-using existing components helps to avoid the loss of “waste” materials to landfills. Because renovation projects are undertaken at the building site, when older materials are torn out they can generate up to 20-30 times as much on-site waste as new construction (Strain 2017). Therefore, carbon savings can be achieved by repurposing waste materials into new functions on-site or for use in nearby construction in another building life cycle. These methods are already widespread in informal and semi-formal housing throughout the world, and much could be learned from those practices for the formal sector as well.

Buildings that last are ones that people are personally attached to.

The lifespan of buildings and infrastructure is not determined solely by physical durability, but also by social, cultural and economic factors (Cao et al. 2021). Buildings that last are ones that people are personally attached to. Emotional and cultural factors can incentivise property owners and especially third-party developers to choose durable materials over those with the lowest initial cost. Materials are fundamental in establishing durable value over time, and the impact that materials have on occupants’ connection to a place transcends mere functional use.