Written by Rebecca Cairns, CNN

Although we're surrounded by millions of them every day, most of us don't think about bricks too often. For thousands of years, the humble clay-fired brick hasn't changed. The building blocks of modern suburban homes would be familiar to the city planners of ancient Babylon, the bricklayers of the Great Wall of China, or the builders of Moscow's Saint Basil's Cathedral.

But the brick as we know it causes significant environmental problems, by using up raw, finite materials and creating carbon emissions. That's why Gabriela Medero, a professor of Geotechnical and Geoenvironmental Engineering at Scotland's Heriot-Watt University, decided to reinvent it.

Originally from Brazil, Medero says she was drawn to civil engineering because it gave her passion for maths and physics a practical outlet. As she became aware of the construction industry's sustainability issues, she started looking for solutions. With her university's support, Medero joined forces with fellow engineer Sam Chapman and founded Kenoteq in 2009.

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Bricks have been a staple building material for at least 9,000 years, and the invention of fired bricks around 3,500 BCE opened up new and exciting possibilities for design and architecture.The ancient temples of Bagan, Myanmar, showcase the amazing possibilities of brickwork. Among the 3,595 temples, stupas, and spiritual structures built between the 11th and 13th century, Dhammayangyi Temple is renowned for its intricate design. The mud-mortar brickwork is so seamless, it's said you can't fit a pin between the bricks. Credit: Mladen Antonov/AFP/Getty Images

The company's signature product is the K-Briq. Made from more than 90% construction waste, Medero says the K-Briq -- which does not need to be fired in a kiln -- produces less than a tenth of the carbon emissions of conventional bricks. With the company testing new machinery to start scaling up production, Medero hopes her bricks will help to build a more sustainable world.

The problem with bricks

Although they're made from natural materials, there are problems with bricks at every step of their production.

Bricks are made from clay -- a type of soil found all over the world. Clay mining strips the land's fertile topsoil, inhibiting plant growth.

In conventional brick production, the clay is shaped and baked in kilns at temperatures up to 1,250°C (2,280°F). The majority of brick kilns are heated by fossil fuels, which contribute to climate change.

A clay quarry in Andalusia, Spain Credit: Jorge Guerrero/AFP/Getty Images

Once made, bricks must be transported to construction sites, generating more carbon emissions.

Globally, 1,500 billion bricks are produced, every year. Laid end-to-end, they would stretch to the moon and back 390 times.

The environmental footprint of different bricks reflects multiple factors including the type of kiln, fuel, and transportation. But with so many produced, their impact adds up, says Medero.

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