Rather than a primary focus on energy efficiency, architects should consider more holistic assessments to reduce the carbon emissions of construction

Thinking Through Material Flows

Rather than a primary focus on energy efficiency, architects should consider more holistic assessments to reduce the carbon emissions of construction

The project is designed to work with the available material and constructive resources. Ninety-six percent of the campus’s materials were excavated, harvested, or sourced from Rwanda. (Iwan Baan)

Kelly Alvarez Doran, a senior director at MASS Design Group, was the keynote speaker at AN’s recent Facades+ New York event. Afterwards, he spoke with AN about moving from the paradigm of sustainability to that of low-carbon sufficiency.

What does the phrase “Less is less” mean to you?

Aside from the obvious nod to Mies, it’s a recognition that we must move past notions of sustaining towards sufficiency. This is a paradigmatic shift: It means advancing beyond mitigating and building resiliency to providing a built environment that is regenerative and circular. Sufficiency means living within planetary boundaries and working collaboratively to ensure everyone’s needs are met. Architecturally this could help us refocus the ways we conceive and construct. We can’t consume our way out of the problem. Adding more and more virgin materials to our buildings has exacerbated carbon emissions. In North America, how can we reconceive what we’ve already built—in terms of buildings, materials, and landscape reuse—and reconfigure the built environment to accommodate different, sufficient models of living? We have built enough floor area to house three to four times the current population of the continent. How we reallocate and reconfigure that floor area is where our focus needs to shift.

map showing material flows overlayed over energy grid metrics in North America
A map shows where the various elements for a window were sourced to be installed in a home designed by Doran for a site in Ontario and completed in 2014. (Courtesy Kelly Alvarez Doran)

Why is the weight of a building important?

The question Buckminster Fuller famously asked Norman Foster of the Sainsbury Centre—“How much does your building weigh, Mr. Foster?”—is as relevant then as it is now, though I suspect his answer would be rather different 45 years later. The answer Foster gave in 1978 reveals the enormity of the blind spot typical of our industry. His accounting of the project’s weight is entirely on-site, leaving all issues of material provenance completely off the balance sheet—most obviously, the weight of the byproducts of mining and processing aluminum and steel that feature so prominently in his response.

The true “weight” of our decisions, socially and ecologically, is something I first experienced when I spent the early part of my career working on and around largescale mines across the world. I have seen the enormous holes, tailings ponds, and refineries where our aluminum extrusions and PVC window frames emanate from. I have also witnessed the scale of impact these extraction sites have on surrounding communities, cultures, ecosystems, watersheds, and the atmosphere.

a worker gathering wood
A worker gathers wood that was used for roof shingles. The Ilima PrimarySchool emitted 28 times less carbon than the global average for an education project. (Courtesy MASS Design Group)

How has your understanding of the role of the architect changed based on your experience in Rwanda with MASS Design Group?

Working in Rwanda required a dramatic unlearning before being able to effectively practice. My North American training to source materials via catalogs and product reps left me ill equipped to design and build in a landlocked country with an 18 percent import tax. Working with local builders through projects like Munini District Hospital quickly revealed my blind spots, notably how simple design decisions have significant social, economic, and ecological impacts. Something as simple as the sizing of a windowpane could improve local livelihoods by enabling it to be sourced in-country or manufactured on-site.

This appreciation of a material’s provenance added an ecological and atmospheric dimension at the Ilima Primary School, where we worked with researchers at MIT to undertake a life-cycle assessment of our projects for the first time. The results shocked us. The building’s embodied carbon footprint (15 kgCO₂e/m²) was 28 times lower than the global average for schools, due entirely to the reliance on locally sourced stone, earth, and wood. This small school, built of locally abundant and readily renewable materials in the middle of the Democratic Republic of the Congo, provided us our first glimpse of the potential for a regenerative architecture.

Munini and Ilima fundamentally shaped my appreciation of the profound responsibility and opportunity we architects and engineers have in addressing the series of crises in front of us. Through a collaborative, holistic approach that sees the entire scope of the challenges and questions the set of assumptions that currently govern our decision-making, we can make the changes required of us.

exterior of a primary school
The curving facade of the Ilima Primary School includes woven screen doors and a roof shingled in wood sourced from a nearby forest. The creation of these elements can be seen in the left image below. (Courtesy MASS Design Group)

How did the Rwanda Institute for Conservation Agriculture (RICA) scale up this holistic approach?

RICA is an architecture of wood, earth, and place premised on sufficiency and regeneration. Working with Arup and Transsolar, we invested in early–design-stage research to identify a material palette that could be harvested from the site itself. RICA’s total weight is sourced almost entirely from the project’s site and immediate surroundings. Our civil and structural engineers dug test pits to ascertain the ideal mix of compressed earth blocks and rammed earth to manufacture low-carbon, durable, thermally massive walls on-site. To place the buildings in a seismic zone, we used stone foundations, resulting in significant reductions of upfront emissions. RICA’s campus of 69 unique buildings is entirely off-grid, which optimized each space for daylight and passive ventilation, reducing power demand and the size of the solar array powering the campus. Our landscape architects worked with ecologists and agronomists to develop a “One Health” design approach that links biodiversity and agricultural yields. Working with Atelier Ten, we developed a silvicultural plan—sustainably managing the health of the school’s environment to benefit the campus and society alike, protecting wildlife habitats, timber and water resources, and recreation areas—to offset the project entirely on site. RICA could be Africa’s first climate positive campus within a decade.

people eating under an outdoor terrace
MASS Design Group’s work takes into consideration a wide range of finishes and objects that can be made by local workers. Here, an outdoor terrace includes numerous locally produced elements. (Courtesy MASS Design Group)

There is a lot to learn about embodied, operational, and whole-life carbon. Where to start?

For decades, our industry has been focused on energy efficiency. That’s only one part of the problem. Reducing operational emissions involves using less: less space, heat, and cooling and less emissive power sources. North American codes are the opposite. They require more layers of highly emissive materials— foams, membranes, sealed units, etc.—to wrap bigger and bigger buildings tighter and tighter, requiring more mechanical systems to pump in oxygen.

To get out of this vicious cycle of consumption, we should follow our European counterparts who have adopted a whole-life carbon policy that looks at embodied and operational carbon over time. What is a project’s total emissions from day one to year ten? What is the time-value of triple glazing or that extra inch of foam insulation from an emissions perspective?

weaves posing with banana fiber-woven objects
MASS Design Group’s campus for RICA is entirely off-grid. Ninety-eight percent of the building’s labor was sourced from within 100 miles of the site. In this image, weavers from Rwanda’s Kayonza district are pictured with items woven from banana fibers. (Courtesy MASS Design Group)

What could architects do now that would have the most impact? One: Learn how to do a life-cycle assessment. It is simple and quickly reveals how simple material changes could avoid hundreds of tons of greenhouse gas emissions. Two: Get together. Collaborate regionally to develop databases and exchange best practices to help us all improve. Three: Challenge and change the codes and systems we’re currently working under. North America zoning bylaws and energy codes need a dramatic overhaul. Europe’s emerging policies, like the Greater London Authority’s Whole Life Carbon guidance and the Netherlands’ focus on material reuse and circularity, provide much-needed precedents at both municipal and national levels. Four: Share. Be generous with your knowledge. From teaching and mentoring to helping a colleague, this is not a zero-sum game but one where a shift to sufficiency will benefit us all.

a worker weaving a screen door
A worker weaves what will become a screen door at the Ilima Primary School. Eighty-three percent of the project’s cost was spent on labor. (Courtesy MASS Design Group)

What gives you optimism?

The velocity of the conversation across the globe around these issues is incredible. Organizations like Architecture 2030, the Carbon Leadership Forum, and London Energy Transformation Initiative
have brought life-cycle thinking into the mainstream. In a decade, I’m hopeful that architects across the world will be more connected to the people and places where they practice and will once again source the bulk of the weight of their buildings from regionally abundant sources.

Kelly Alvarez Doran is an architect, educator, and activist. He is the senior director of Performance & Provenance at MASS Design Group and the director of the Ha/f Research Studio at the University of Toronto.