GB&D: Hempel on Renovations vs. New Construction

As young architects we grow up excited about the opportunity to design a new building from the ground up. In school we’re often taught by example and training to take a site, the blank canvas, and create a vision for a completely new structure.

In the face of the realities of climate change, we need to adjust our thinking. The real battle to reduce the building industry’s effect on the environment will be fought in how we address the massive stock of aging and existing buildings. A 2012 survey by the US Energy Information Administration found that half of the country’s 5.6 million commercial buildings—including office, hospitality, education, and health care facilities—were constructed before 1980. Two-thirds of the building area that exists today will still be in use in 2050, according to industry estimates.

For every new building we build there are hundreds of existing buildings that need the same level of care and design to mitigate their emissions. Outdated mechanical systems and underperforming envelopes are large contributors to the building industry’s carbon emissions, which account for nearly 40% of total global greenhouse gas emissions, according to the Global Alliance for Building and Construction. Currently, building renovations affect only 0.5 to 1% of the building stock annually, according to data compiled by nonprofit group Architecture 2030.

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As an industry we need to focus the same creativity and innovation we apply to new buildings on renovations. The old phrase, “the greenest building is the one already built” is truer now than ever. If we’re really going to affect climate change, we need to address the existing stock of buildings. That starts with recalibrating how we analyze and evaluate older buildings, ensuring we are maximizing the life cycle and value before tearing it down. As architects, we need to find the same passion, opportunities and beauty in renovations as we do for new buildings.

A Different Approach

Renovation has always been part of what architects do, but resiliency and climate change mitigation have increased awareness of its importance. The calculation for determining whether to renovate or tear down has changed. There are more factors we need to consider, more data available to shape options.

In the past the importance of embodied carbon was rarely discussed. There was little consideration given to the materials, manufacturing, or the transportation-related carbon emissions associated with renovations vs. new construction, nor the sustainability impact of demolishing the building, removing the waste, and repeating the construction process.


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