The House That Termites Built

Eastgate Centre in Harrare, Zimbabwe 

Eastgate Centre is a large shopping mall and office center. It stands in the heart of the business district in Harare, the most populous city in Zimbabwe, Africa.

It's a very big building, occupying half a city block. The interior is elegant and modern, with small boutiques on the ground floor and a large interior space with cool fountains, hanging catwalks and steel pillars straight out of a science fiction movie.

Interior atrium of Eastgate Harrare. 

The shopping center is made of two nine-story office towers, which are connected by a glass atrium that lets in the light and keeps out the rain. On the surface, it might look like any other modern mall in the world, but Eastgate has a secret. This is very special building.

Eastgate uses very little artificial air conditioning, compared to other structures in the tropics. The city of Harrare has a high elevation and a temperate climate, with daily temperatures out   

Would you believe it was designed by termites?

Mick Pearce, an architect from Zimbabwe.

Mick Pearce, an architect from Zimbabwe, was the designer of Eastgate Harrare. His style of architecture is based on a science called biomimicry. In science and engineering, biomimicry happens when humans copy the forms and the processes they find in nature: the word literally means "imitating life".

The great architects of the insect world, the mound-building termites

The natural forms that Pearce studied to build Eastgate Harrare were created by some of the greatest architects on our planet: the mound-building termites. 

Mound-building termites come in many different varieties and are found throughout Africa, southern Asia and Australia. They are named for the towering mounds they build out of hardened clay. These mounds can be over five meters tall (25 feet)  and twelve meters in diameter (40 feet), and incorporate many tons of earth. They can be very impressive on the outside...but on the inside, they are even more amazing.

An African termite mound

Termites are hardy insects with a social structure that allows them to cooperate to achieve great things. Their mounds are not just tall and massive but very elegantly built to provide a controlled environment inside, with very restricted temperatures and humidity.

The reason that termites need such a regulated environment is that their lives depend on farming. Underneath the mounds, they grow an elaborate fungus garden, which provides them with nourishment. Although the termites are fairly tough, the fungus garden can be delicate, and needs a regulated temperature and humidity--like the greenhouses that we use to grow fruits and vegetables.

Interior drawing of a termite mound - the fungus garden is in the middle!

In order to provide a stable environment for their farms, the termites have to build a home with a very well-regulated temperature and humidity. The temperature and moisture must never fall below or rises above the conditions that the fungus needs to thrive.

The termites have to achieve this stability in some of the hottest and driest climates on Earth. In Africa and Australia, daily temperatures can soar to 42 degrees Celsius (over 107 Fahrenheit) or drop to below freezing at night. And unlike humans, termites cannot rely on technology to provide them with air conditioning or artificial heat!

Nevertheless, the temperature and humidity inside a termite mound rarely varies more than a few degrees year round. Their fungus gardens continue to grow, and their colonies continue to thrive.

Know your air flow: termite mound versus office building

How Do They Do It?

Both Mike Pearce and the termites begin the building process by knowing their environment. The human architect makes a point of studying the "micro climate" of his future build site, the place where the structure will someday stand.

Pearce gathers information about the daily and nightly temperatures, the rainfall, the path of the sun and the flow of wind and air currents. Termites do the same! Their mounds are often placed to avoid the worst of the direct sun. They use the thickness of the walls to resist heat, and cleverly build channels and chimneys to direct the flow of air through their mounds.

This keeps the chambers where the termites live very comfy! The tropical heat stays in the parts of the mound where they don't spend as much time. The mound has so many clever chambers and channels that it serves as a giant lung, breathing in fresh cool air into the lower levels, and venting hot dry air out the chimneys.

Eastgate Air Flow - how the chimneys work

The walls and chimneys of Eastgate Harrare follow this model. The building uses passive cooling and keeps the indoor temperature stable year round. Eastgate uses almost no air conditioning. The building uses 35% less energy than other buildings in the city, and the lower energy bills makes the rents in its offices less expensive too. It also means that during power outages, the building can often remain open and useful while other buildings must shut their doors!

By not adding a full central air conditioning system, Mike Pearce also saved 10% of the cost of the building, 3.5 out of 35 million dollars.

Mister Pearce learned a lot while building the Eastgate Center. Some of his other projects have been even more successful. One of his buildings in Melbourne uses 70-80% less energy use than other buildings in the city!

A House That Termites Built is much less expensive, and saves millions of dollars in energy bills over time. But perhaps most importantly, it makes a more sustainable future for all of us.

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WANT TO LEARN MORE?

The Eastgate Harrare building is a very interesting place for those who want to build Smart Spaces, human structures which are more energy efficient and environmentally friendly. To learn more about Eastgate Harrare and biomimicry, check these links.

MICK PEARCE - This is the personal website of the architect, Mick Pearce. It has great videos, Powerpoint presentations and essays for students about his work around the world, and about his fascination with termite mounds or "terminaries".

BIOMIMETIC ARCHITECTURE: Green Building in Zimbabwe Modeled after Termite Mounds -
This is an image gallery of the Eastgate Harrare building and the termite structures on which it was based.

Termites, their social organization and their knack for architecture are also really fascinating subjects. To find out more about them, check these links:

TERMITES ARE TEACHING ARCHITECTS TO DESIGN SUPER-EFFICIENT SKYSCRAPERS - This is a quick article in Wired Magazine, but it has quotes from both biologists and architects who study termite mounds and apply their architecture to human buildings to save energy.

WHY TERMITES BUILD SUCH ENORMOUS SKYSCRAPERS - This is an article from BBC Earth, and goes deeper into termite behavior and technology. You also get to read about real termite scientists at work, and how the termites fight back against their intrusions!

COLLECTIVE MIND IN THE MOUND - An article from National Geographic featuring great photos and science about mound-building termites.


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ABOUT THE AUTHOR

Arinn Dembo is a professional science fiction writer and software developer working in Vancouver, BC. She has degrees in Anthropology and Classical and Near Eastern Archaeology, and volunteers as a science educator at Vancouver's The Learnary, where she teaches an ongoing series of workshops called Gothic Science.