From Home to Factory
It is early morning, around 7:30. The workers next door have already started. I can hear the concrete mixer turning, the hammer striking, the loud conversation that accompanies the work. As I sit at home and write, a new building is rising beside me. It is an assembly of reinforced mass: columns, slabs, and beams stacked with the density of a bunker. Watching the workers pour the gray slurry into the molds, it does not feel like a house is being built. It feels like a fortress being cast.
On the drive to my factory, the pattern is relentless. Every construction site along the road follows the same heavy logic. There is no distinction between structural necessity and incidental form—everything is a full, monolithic pour. We build as if every garden wall and every storefront must withstand a siege.
Inside the industrial park where I work, the logic reaches its limit. Factories are not merely enclosed; they are sealed behind continuous concrete walls. These are not boundaries that breathe; they are barricades.
From home to factory, the language is identical: build solid, build heavy, build as if the earth itself cannot be trusted.
Seen once, it is a construction project. Seen a hundred times along a single road, it becomes a pattern. And when a pattern repeats across every new development in a growing city, it is no longer a series of individual decisions. It is a logic—unspoken, shared, and self-reinforcing.
The Scale of Change
None of this is to deny the scale or importance of the transformation Addis Ababa is undergoing. The changes are visible and, in many ways, long overdue. Roads are being expanded and reorganized. River corridors are being cleared and rehabilitated. Public spaces—parks, walkways, and open areas—are being created where disorder once prevailed.
For a city that has grown rapidly and often informally, this effort carries real significance. It signals coordination, intent, and the capacity to act at scale. It also restores a sense of order and dignity to the urban environment—something that matters not only functionally, but psychologically. A capital city, especially one that represents a country with Ethiopia’s history and ambitions, cannot remain indefinitely in a state of neglect.
There is also a practical dimension. Infrastructure must be built. Public space must be organized. Circulation must be improved. The question is not whether Addis Ababa should build—it must.
But acknowledgment of necessity should not obscure a second question: how the city is being built, and whether the material logic that now dominates this transformation is the only way such renewal can occur.
When in Doubt, Build Heavy
What the transformation reveals, however, is not just a series of projects, but a consistent underlying approach. Across buildings, infrastructure, and public space, a single material logic appears to dominate: cement and steel as the default solution.
This is not a matter of isolated choices. The same construction pattern repeats across different sites, scales, and functions. Roads, walkways, river edges, buildings, and boundaries are all treated with a similar assumption—that solidity, continuity, and mass are the safest and most appropriate forms of construction.
In principle, these materials are indispensable. They enable strength, durability, and scale. In practice, however, they are being applied with little visible distinction between where such strength is required and where it is not. What should be a matter of engineering judgment—matching material to function—begins to appear as a habit.
The result is not simply a city that is being built, but a city that is being built according to a shared, unexamined logic: when in doubt, build heavy.
The Error
At the center of this logic is a simple but consequential error: the city is being built as if every element must carry load.
In any built environment, there is a fundamental distinction between what is structural and what is not. Columns, beams, and foundations must bear weight and resist forces; they justify the use of reinforced concrete and steel. But much of what makes up a city—walkways, boundary walls, public surfaces, embankments, and even portions of buildings—does not operate under the same structural demands.
Yet this distinction is increasingly blurred. Surfaces that could be light are made heavy. Elements that could be modular are cast monolithically. Boundaries that could define space are built to resist intrusion. The result is a systematic overextension of structural logic into areas where it is not required.
This overextension rests on a set of implicit assumptions. Strength is equated with mass. Permanence is equated with solidity. Order is equated with continuous, unbroken construction. These assumptions are rarely stated, but they shape decisions across projects and scales. The issue, then, is not the presence of cement and steel. It is the absence of restraint in their use.
The Consequences — Carbon, Heat, and Water
The consequences of this construction logic are measurable. They are not abstract.
Start with carbon. Cement production emits roughly 0.6 tons of CO₂ per tons produced and accounts for about seven percent of global emissions. At the scale of a single building, this may appear marginal. At the scale of a city-wide transformation—roads, embankments, walkways, buildings, and public spaces—it becomes a large, front-loaded carbon burden embedded into the urban fabric for decades.
The thermal effects are already visible in Addis Ababa. Satellite-based studies show that land surface temperatures in the city have increased by approximately 7.9°C between 1990 and 2020, driven largely by the expansion of built-up areas and the decline of vegetation. Nearly 46 percent of the city now falls into the highest thermal stress category. Built-up surfaces contribute roughly +4.3°C to local temperatures, while vegetation offsets this by about −2.6°C. A five percent increase in built-up intensity raises temperature by about 1.6°C, while a five percent increase in vegetation reduces it by about 1.4°C.
An increase of this magnitude does not simply register on a thermometer. It changes how the city feels. This is already visible in everyday behavior: people walk under umbrellas—not because of rain, but to shield themselves from both the direct sun and the heat rising from tarmac and concrete surfaces. What was once a simple walk has become an exercise in avoiding exposure. The heat is no longer only overhead; it is reflected upward and radiated outward. Surfaces that were once warm become hot to the touch, and spaces that once cooled after sunset retain heat late into the night. As hard surfaces expand, more of the city begins to feel like exposed pavement at midday.
The hydrological consequences follow the same logic. Flood-prone areas in Addis Ababa have expanded dramatically—from about 80 km² in 1984 to nearly 288 km² in 2020, with projections reaching over 360 km² by 2030. During the same period, impervious surfaces increased sharply, while vegetation declined. What is striking is that this increase in flood risk has occurred without a strong historical increase in rainfall. The primary driver has been urban form: the replacement of permeable ground with hard, continuous surfaces.
This is not only visible in projections; it is already experienced. Even after relatively light rain, roads fill with water, shallow ponds form along streets, and movement slows as drainage systems are quickly overwhelmed. What was once absorbed into the ground now remains on the surface. This means the city is already becoming more flood-prone because of how it is built. Climate change will intensify rainfall in the future, but the underlying vulnerability is being constructed in the present. The same surfaces that trap heat also accelerate water.
Taken together, these effects point to a single conclusion. The issue is not simply that Addis Ababa is building with cement. It is that the prevailing construction logic is reshaping the city’s thermal and hydrological systems in ways that increase long-term risk.
Unequal Burden — Who Lives With This
These consequences are not evenly distributed, and the scale of exposure is growing.
Addis Ababa’s population has expanded rapidly over the past decades, from well under two million in the early 1990s to roughly four–six million today, with projections approaching eight million by 2030. Much of this growth has not been absorbed through planned, serviced expansion, but through informal and semi-formal settlement.
Estimates suggest that a substantial share of the city’s residents—often cited in the range of 60–70 percent—live in informal or underserved conditions. These areas are not randomly distributed. They are frequently located along riverbanks, in low-lying zones, or in parts of the city where land is available but infrastructure is limited. These are precisely the areas where the effects described earlier are most acute.
Flood exposure provides a clear illustration. Recent assessments indicate that 67 percent of Addis Ababa’s population lives in flood-prone areas, and that exposure is projected to increase as both population and built-up area expand. At the same time, about 10 percent of new development in the past decade has occurred within the existing 100-year floodplain, further concentrating risk.
Heat follows a similar pattern. In dense, low-income neighborhoods, where vegetation is limited and construction materials retain heat, the urban heat island effect is amplified. Buildings trap and re-radiate heat, and the absence of shaded public space increases exposure for those who rely on walking and outdoor activity.
The capacity to adapt is also uneven. Access to shaded streets, well-drained infrastructure, and thermally moderated buildings is not evenly distributed across the city. Those with fewer resources depend more directly on the immediate environment, and therefore experience more directly the consequences of its design.
The result is a form of uneven urban exposure. The same construction logic that produces visible improvement at the scale of the city concentrates risk at the scale of everyday life. Heat and water do not distribute themselves evenly; they accumulate where the city is least able to absorb them. The city may be improving in appearance while becoming harsher in lived experience for those least able to absorb its risks.
A Different Design Principle
If the problem lies in treating every element of the city as if it must be built heavily, the alternative begins with a simple distinction: not everything is structural.
This is not an argument against cement or steel. These materials are essential where strength, durability, and safety demand them. Foundations, load-bearing elements, and critical infrastructure require precisely this level of robustness. The issue arises when the same logic is extended indiscriminately to surfaces, boundaries, and spaces that do not carry comparable structural demands.
A different approach begins by restoring that distinction. Build heavily where necessary; build lightly everywhere else.
This principle does not reduce ambition. It redirects it. It asks that material be matched to function, rather than applied by default. It replaces uniformity with judgment. In practice, this means asking a set of simple questions at the point of design: Does this element need to carry load? Does it require continuous, monolithic construction? Can the same function be achieved with less material, more permeability, or a combination of structural and non-structural systems?
Where the answer is no, lighter approaches become not a compromise, but a more appropriate solution. The shift is therefore not from one material to another, but from material substitution to material minimization. It is a shift from standard forms to function-based design, and from the assumption of maximum load to the discipline of sufficient performance.
Such an approach does not stand apart from Ethiopia’s broader direction; it aligns with it. The country’s Green Legacy initiative and related urban greening efforts emphasize expanding vegetation, improving environmental quality, and restoring ecological balance. Extending these principles into the material logic of urban construction—reducing unnecessary hard surfaces, increasing permeability, and integrating vegetation as infrastructure—moves these initiatives from surface-level greening to structural transformation.
At the scale of a city, this distinction accumulates. Applied consistently, it reduces embodied carbon, lowers heat retention, improves water absorption, and creates spaces that are more adaptable over time. The question, then, is not whether Addis Ababa should continue to build, but whether it can begin to build with greater precision—using weight where it is required, and restraint where it is not.
What This Looks Like in Practice
At its core, the alternative is simple: work with natural systems rather than attempting to override them. Not command and control, but adaptation.
This shift becomes most visible in housing. There is no structural reason for most houses to be built entirely out of reinforced concrete—from foundation to columns to walls to every partition, and even to the perimeter walls that enclose them. Structural strength is required in specific elements: foundations, columns, beams. But walls, especially internal and non-load-bearing ones, do not need to carry that same burden, and boundary walls are rarely load-bearing at all. Yet the prevailing approach extends structural material to the entire building and its enclosure, turning what could be a selective system into a fully hardened mass.
An alternative is straightforward: build the structure where it is needed, and build lightly where it is not. A reinforced frame can provide strength, while walls can be constructed from lighter, more adaptive materials—block, stabilized earth, timber systems, or other locally appropriate solutions. This reduces material use, lowers heat retention, and creates buildings that respond better to their environment rather than storing and radiating heat throughout the day.
There is also a temporal dimension to this choice. When buildings are constructed as continuous, monolithic systems, any modification—whether to expand, repair, or adapt—often requires demolition. Walls cannot be easily removed or reconfigured without affecting the whole. By contrast, when structural and non-structural elements are clearly separated, change becomes possible without destruction. Openings can be introduced, spaces reconfigured, and extensions added incrementally. This reduces the cost of change and allows households to adapt their homes over time rather than rebuilding them entirely.
The same principle applies beyond the building itself.
Take water. Instead of treating rainfall as something to be removed as quickly as possible, parts of the urban surface can be allowed to absorb and slow it. Even small interruptions—unsealed edges, planted strips—reduce runoff and prevent the immediate pooling that is now common after light rain.
Take heat. Rather than relying on fully exposed hard surfaces, spaces can be structured around shade as a primary element—trees, covered walkways, and surface variation that reduce heat at the point of experience and allow the city to cool.
Take boundaries. Instead of continuous, sealed concrete walls, edges can define space without fully enclosing it—using lighter systems or vegetation that allow airflow and reduce heat buildup while still providing separation.
These examples are not exhaustive. They illustrate a broader shift: the city does not need to be built as a fully controlled environment to function effectively. In many cases, allowing permeability, shade, and material variation produces better outcomes than complete enclosure and continuous hardening. The question, then, is not which specific alternative to adopt, but whether the underlying approach can change—from building against natural processes to building in alignment with them.
From Principle to Policy
If the issue is not the absence of rules but the logic embedded within them, then the response cannot be limited to more regulation. It must begin with changing what the system encourages by default.
At present, the implicit standard is clear: build continuously, build heavily, and build permanently. This is not always mandated explicitly, but it is reinforced through approval processes, design norms, and risk-averse decision-making. The result is predictable—overbuilding becomes the safest choice.
A different approach does not require abandoning standards. It requires adjusting what those standards prioritize.
First, introduce a clear distinction between structural and non-structural elements in building codes and approvals. Where load-bearing performance is not required, designs should not default to reinforced concrete. Allowing and legitimizing lighter wall systems, modular construction, and mixed-material approaches would immediately reduce unnecessary material use without compromising safety.
Second, move from requiring continuous hard surfaces to allowing—and in some cases requiring—interrupted surfaces. Road edges, walkways, public spaces, and non-critical surfaces can incorporate permeability as a standard design feature. This is not an aesthetic choice; it is a functional requirement tied to drainage and heat.
Third, integrate water absorption and retention into urban design criteria. Instead of evaluating projects solely on their ability to remove water, include their capacity to absorb and slow it. This shifts drainage from a purely engineering problem to a design consideration.
Fourth, recognize adaptability over time as a policy objective. Building systems that allow modification without demolition should be encouraged through permitting and design guidelines. This reduces long-term costs and aligns with how households and businesses actually evolve.
Finally, align these shifts with existing national priorities. Ethiopia’s Green Legacy and urban greening initiatives already emphasize vegetation, environmental quality, and resilience. Extending these principles into construction standards and approval processes ensures that greening is not limited to planting, but embedded in how the city is built.
None of these changes require a complete overhaul of the system. They require a recalibration of what is considered normal. The question for policy, then, is not whether to build more or less, but whether the rules of building can shift—from reinforcing uniform heaviness to enabling selective, adaptive construction.
Building With Restraint
I return to the image that began this piece. A house rising next door, poured in layers of reinforced concrete, dense and immovable. A factory enclosed behind continuous walls. A city taking shape through repetition—solid, sealed, and unyielding.
Seen individually, each of these choices makes sense. They promise strength, permanence, and order. But seen together, across the length of a road, across neighborhoods and new developments, they reveal something else: a way of building that has become automatic.
That is the real issue.
Addis Ababa does not suffer from a lack of effort, investment, or ambition. The ongoing transformation of the city reflects all three. The question is whether the logic guiding that transformation is aligned with the environment in which the city exists.
A city cannot cool itself while continuously hardening its surface. It cannot absorb water while sealing the ground beneath it. It cannot adapt over time if every element is built as if it must never change.
(Tsegaye Nega (PhD) is a Professor Emeritus at Carleton College in the United States and the Founder and CEO of Anega Energies Manufacturing.)
Contributed by Tsegaye Nega (PhD)
