The Importance of Adaptive Reuse in our Built Environment

Guest Post by Emma Walsh.

Adaptive reuse, within architecture, is defined as a process in which buildings are adapted for new uses while retaining their historic fabric and features. This approach enhances both the space and experience of a structure while also reducing the carbon footprint associated with its construction. By reducing the amount of energy associated with demolition and the subsequent raw materials needed for the construction of an entirely new building, adaptive reuse can be utilised as an essential tool in the future of environmentally conscious architecture.

Previously, only buildings of architectural or historical significance have tended to receive an interest in reuse or adaptation. However, in recent years a broader concept of retrofitting has been established out of environmental necessity. This movement places an importance on the conservation of energy in the face of the climate emergency. As carbon emissions and energy consumption need to be reduced, it is recognised that the demolition of existing buildings dissipates and wastes the energy within historic structures. It takes an estimated sixty-five years for an energy-efficient new building to recapture the amount of energy lost in demolishing an existing building (1). Further energy is then required to build a new structure, exacerbating the energy waste with a new build. This clearly demonstrates the environmental benefits of adaptive reuse.

The World Green Building Council’s most recent report calls for all new buildings to have forty percent less embodied carbon emissions by 2030 (2). Reusing and reinventing old buildings significantly increases the building sectors ability to achieve this goal. By updating current buildings with different climate strategies, the construction industry can move forward with sustainable development for the future.

As things currently stand, according to the United Nations environment programme, buildings and their construction account for thirty-eight percent of global energy use and thirty-nine percent of energy-related carbon emissions annually (3). Twenty-eight percent of these carbon emissions come from the operational emissions of a building, such as heating and ventilation. The remaining eleven percent are ‘’upfront’’ carbon emissions, that is, associated with materials and construction processes throughout the whole building lifecycle (4).

Adaptive reuse reduces the amount of raw material required to produce a new structure. This construction process adapts the materials already available at hand, using more minimal interventions in order to retain the historic fabric. As well as this, the absence of the demolition of a structure further saves energy. Demolition is an energy intensive construction approach which is required for a new build. Adaptive reuse must also encapsulate a revaluing of the building stock we currently have.

In addition, adaptive reuse can enhance our built heritage and display the chronological layers of construction that depict our past. Stewart Brand addresses this in his book How Buildings Learn (1994), in which he discusses retrofitting and the adaptive ability of a building’s interior: ‘interiors change radically while exteriors maintain continuity. The space plan is the stage of the human comedy. New scene, new set’ (5). Throughout the book, Brand provides numerous examples of the successful employment of adaptive reuse to enhance the space of a building. The enhancement of the built heritage of a town or city also has many practical benefits, such as helping to increase the attractiveness of a location as a tourism destination, as evidenced by the Open House Project conducted by the EU (6).

The construction industry consumes almost the entire supply of cement produced throughout the world (7). It also accounts for twenty-five percent of all plastics, twenty-six percent of aluminium output, and fifty percent of all steel production (8). The consumption of resources by the construction industry and the carbon emissions associated with this continues to soar yearly. Upon the practical completion stage of a typical office development, thirty-five percent of the structure’s whole-life carbon will have already been emitted, with residential buildings emitting fifty-one percent of the whole-life carbon emissions upon completion. The act of construction itself heavily pollutes our environment, accounting for four percent of particulate emissions each year and causing more water pollutant incidents than any other industry (9).

Pollution is further emphasised by an industry which bases its economic model on waste. Each year, more than fifty-thousand buildings are lost to demolition. Demolition is a very costly solution for urban development, as well as being an environmental problem. In the United States alone, demolition debris accounts for twenty-two percent of the country’s solid waste stream, as demolition and landfills remains the most frequently used method of removing and replacing existing structures (10). Over 300,000 houses in the US are demolished annually, generating 161.9 million tonnes of construction waste.

Adaptive reuse can significantly reduce the raw material consumption of the building industry. Adaptive reuse does not require demolition, an energy-intensive process, or the raw materials consumed by new-build construction. This reduces pollution and energy waste. Governments need to put in place policies and incentives to facilitate the deconstruction of materials as opposed to the demolition of buildings, as well as developing technologies for safe deconstruction and reuse.

Emma Walsh graduated from University College Cork with a BSc in architecture in October 2020. The title of her dissertation was ‘Architectural Palimpsest: the benefits of adaptive reuse in relation to climate change’. Emma’s research interests include adaptive reuse, retrofitting, and environmental architecture. She currently works as an Architectural Assistant. In the future, Emma hopes to pursue a Masters degree in architecture. You can follow her on LinkedIn.