Toward a path to zero carbon: building renovations and circular economy principles

April 25, 2024

Toward a path to zero carbon: building renovations and circular economy principles

By JENN CHEN and JUSTIN SCHWARTZHOFF
LMN ARCHITECTS

The embodied carbon footprint of an interior renovation can be drastically reduced by taking ownership of what already exists in a space, repurposing materials rather than sending them to a landfill and seeking out unused stock.

How does the building industry align around radical, pragmatic decarbonization? Along with addressing climate pollution from energy use, we also must address the climate pollution that comes from manufacturing construction materials like concrete, steel, and even carpet and furniture. Known as embodied carbon, this pollution is around 20% of global greenhouse gases, and represents the next frontier in decarbonization. The solution toolkit includes building reuse and circular economy, sustainably-sourced mass timber, zero-carbon concrete and steel, structural materials efficiency, agricultural-waste biogenic materials and all-electric construction vehicles.

Since 2020, LMN Architects has led an industry-wide collaboration to uncover the challenges and consolidate solutions on carbon reduction through the Path To Zero Carbon series. With dozens of experts and peers involved, this provides the first comprehensive view of AEC carbon pollution and solutions.

CIRCULAR ECONOMY AS A KEY SOLUTION

Among solutions, transitioning to a circular economy is one of the most important. What is a circular economy? It means keeping materials, products and buildings in continual use instead of sending them to a landfill. From bricks and insulation to furniture and whole buildings, this means designing for timelessness, durability, and deconstruction, as well as salvaging from existing buildings, building a local refurbishment economy, and warehousing of refurbished products.

How does the circular economy impact carbon? In the case study below, buying best-in-class low carbon new products might have led to a 22% reduction in carbon, but by engaging the circular economy, the team realized a 65% embodied carbon reduction.

Chen

Schwartzhoff

Materials also can have stories that contribute to design; from the old brick and reclaimed wood character we love in coffee shops to materials like ceiling tiles and workstations that can be refurbished to be indistinguishable from new. Circular economy platforms and products like Rheaply, Reseat, Davies Furniture, and Doors Unhinged already exist nationally in some product categories, and local options exist in most cities.

RETHINKING RENOVATIONS

Office renovations are often excluded by embodied carbon measurements, ratings and ESG accounting. Major certifications systems, such as LEED, allow interiors material to be excluded from embodied carbon calculations (also referred to as Life Cycle Analysis or LCA). A lack of carbon data (Environmental Product Declarations or EPDs) for interiors materials makes tracking emissions more difficult even if an owner wants to include them.

This is a huge potential oversight, as an early LMN study on interior renovations suggested that interior renovations could make up the largest percentage of embodied carbon over 60 years, larger even than building envelope and structure. Renovations have accelerated as well, and often require a restoration clause that requires tenants to remove everything from their space when their lease is up, even if carpet, walls, ceilings and furniture have a decade or two of useful life remaining.

Office furniture alone is estimated to account for over 8.5 million tons of waste per year. Worse, most office furniture is designed to function for 10-15 years, but with the short refresh cycle of seven years or less, much of this furniture is being sent to the landfill with years of useful life remaining. And with offices downsizing to accommodate a shift to hybrid work, this volume of furniture waste will likely increase over the next few years.

Can we rethink renovations? Starting with what exists already in a building and space, can existing materials and layouts remain in place as part of a thoughtful, new design instead of being removed? Can we capture the economic and carbon value of used materials instead of landfilling them?

PATH TO ZERO-CARBON INTERIORS