Cool Mud Beats Concrete for Building Homes in a Hotter Africa

By Katarina Hoije

IT’S A SWELTERING 90F in Kaya, the midday sun beating down on the low-slung city in central Burkina Faso. But inside the Morija Medical Clinic on the outskirts, vaulted ceilings made of pressed adobe keep the temperature several degrees cooler.

“Burkinabé builders have used mud for generations to build smaller dwellings, but also multistory buildings and impressive mosques,” says Clara Sawadogo, the 35-year-old Burkinabé architect who worked on the clinic with Switzerlandbased firm Nomos Architects, placing her hand on a massive earthen wall. “Can you feel it’s cooler? That’s because the walls are breathing, literally. The mud lets the air circulate. Unfortunately, much of the technique has been forgotten.”

Sawadogo is at the vanguard of a young group of architects in West Africa’s arid Sahel who employ traditional building techniques, using mud, wood and stone to construct buildings adapted to the changing climate in a place that’s experiencing increasing drought, fluctuating rainfall, and extreme temperatures. Among her cohort are Mariam Kamara from Niger and the world-renowned Burkina-born and Berlin-based architect Diébédo Francis Kéré, who won the Pritzker Architecture Prize, often referred to as the Nobel in the field, in March.

The Morija clinic is a prime example of the style, with its earthen textures and rounded shapes inspired by Nubian vaults, and of the methods these designers employ. Thick outer walls are made using sedimentary rocks from a nearby pit. The whole building is angled toward the prevailing winds and surrounded by vegetation that provides shade. The clay roof and vaulted inner ceiling use natural convection to create a breeze, and used together they remove the need for air conditioning. Architect Clara Sawadogo outside the Morija Medical Clinic she co-designed with Nomos Architects in Kaya, Burkina

Faso. Source: Bloomberg QuickTake

Adobe and compressed-earth blocks have greater thermal inertia than concrete, which means they’re more resistant to the

heat outside. Source: Bloomberg QuickTake

Adobe, rammed earth (compacted soil that includes sand, gravel and clay), and the compressed-earth blocks that Sawadogo often uses in her buildings have greater thermal inertia than concrete, which means they’re more resistant to the heat outside. Used in combination with careful orientation of the building, they help lower energy consumption during the hot season, when demand peaks.

Kéré’s success shows how the use of raw earth-based materials is gaining stature internationally. But Sawadogo says that at home, she’s often met with disbelief. The

“Mud can be just as resistant as cement,” Sawadogo says. “It’s a question of quality, the materials you use and the construction.” Source:

Bloomberg QuickTake

capital Ouagadougou is mostly made up of chunky concrete constructions with flat roofs where residents hang laundry or keep chickens and goats.

“‘Mud doesn’t last,’ they’ll say,” Sawadogo says. “They’ll then go on recounting horror stories of mud constructions collapsing during the rainy season, trapping their owners inside. Mud can be just as resistant as cement. It’s a question of quality, the materials you use and the construction. Without a strong foundation and a sturdy roof, any house will collapse.”

Sawadogo was born in Ouagadougou, but it was during her architecture studies at the University of Lyon in France that she became interested in the tradition of her country’s Gurunsi people of building their houses entirely using local materials such as mud, wood, and straw.

Across West Africa, the tradition of building houses in mud dates back centuries. Cities such as Agadez in Niger and Bobo-Dioulasso in Burkina Faso are dominated by grand central mosques — towering triangular structures of red pressed-earth bricks. During France’s colonization in the first half of the 20th century, builders started mixing cement with traditional materials. Over the years, concrete became the dominant material, because it’s seen

The mud-brick Agadez Mosque in Niger was built in the 16th century. Photographer: Christopher Pillitz/

Getty Images

Cool Mud from page 55

as more stable and is easily available from the country’s half-dozen factories. Globally, the highly energy-intensive production of cement (a key ingredient in concrete) accounts for some 8% of carbon emissions.

“People seem to think that concrete is a safer investment,” Sawadogo says. “They prefer cement even if it’s so hot at night that they can’t sleep.”

Like many African countries, Burkina Faso has done very little to cause climate change. It will, however, suffer a disproportionate brunt of its impact, even as it doesn’t have enough resources to adapt. The landlocked nation contributes just 0.08% of global emissions but ranks 159th out of 181 countries in the Notre Dame Global Adaptation Initiative Country Index, which indicates a nation’s vulnerability to climate change in combination with its readiness to improve resilience. Burkina Faso could see a temperature increase of up to 1.6C by 2050 and up to 4C by 2099, according to the United Nations Development Program, or 2.5 times the global average.

“In Burkina Faso we’re already living the reality of climate change. We need to start preparing, and we have all the tools to do so right here,” says Sawadogo. “If we could just train builders, we’ll be able to make mud houses more affordable. In the end it’s about building homes that are comfortable to live in even as the climate gets hotter.” https://www.bloomberg.com/news/ features/2022-11-02/how-traditional-west-africanarchitecture-keeps-homes-cool Video: The Architects Building Future Cities With

Mud (view from the source article, link shown above)