History of the Brick: Testimony to that Ubiquitous Building Unit. The brick as a standard unit of building and construction has endured through the ages. Why?
The Origin of the Dwelling-House
The brick is that ubiquituous unit used in construction, a small rectangular block of clay, dried and kiln-fired in the millions that go into building our homes, town and cities. In his book, The Ten Books on Architecture, Roman writer Marcus Vitruvius Pollio (c. 70-15 BC), describes the building of a wall using an attractive ‘brick bond’, that is, the pattern used in laying down the bricks. He also describes three types of brick. My Oxford Dictionary of Architecture lists over sixty different kinds of brick, and over eighty different brick bonds. However, the brick is not just another innocuous unit, used in construction. The brick pre-dates even Roman architecture.
Mesopotamia and the Sumerians
The advent of the brick represents a quantum leap in the evolution of thought, In The Grid Book, author Hannah B Higgins, lists the brick as one of ten ‘grids’ that have changed the world. How did the brick originate? Mesopotamia is the ancient name of the great, Middle Eastern plain that today covers Iraq, parts of Syria, Iran and Turkey. The area is irrigated by two rivers, the Tigris and the Euphrates. About 5000 BC, the lower Mesopotamian valley was occupied by the Sumerians. The origin of these people has always been a puzzle. Today, we have the remnants of their culture to show that they were advanced in mathematics and astronomy, agriculture and engineering.
The Sumerians learned to control floods from their rivers, and build fortress towns. In the centuries that followed, nomad shepherds from the deserts that surrounded the fertile crescent began to settle in these towns. They adopted agriculture and absorbed other strands of Sumerian culture. Slowly, they began to build their own cities, incluing Babylon, and formed their own city-states. In Mesopotamia, the city-states were under the protection of the god of the city, and at the heart of the city was the temple.
The most prominent part of the temple was the ziggurat, or temple tower. The ziggurat of Ur dates from 2100 BC, and was built of sun-baked bricks. Somewhere along the timeline of history, these ancient people learned to collect mud left by the flooding rivers, mold them into bricks and bake them in the sun. The result was at least sophisticated enough to build their temples. Interestingly, around the time of the building of the temple at Ur, another great civilization was emerging west of the Red Sea. The Egyptians also built massive temples, and tombs to house their dead kings. However, they used the available blocks of stone, and didn’t need to make bricks.
Mud and Sand
Two thousand years later, the Romans were using bricks in the construction of their dwelling-houses. In his book Vitruvius describes the brick-making process: “I shall state of of what kind of clay they (the bricks) ought to be made. They should not be made of sandy or of pebbly clay, or of fine gravel…they should rather be made of white and chalky or of red clay…these materials are smooth and therefore durable; they are not heavy to work with, and are more readily laid.” Today, mud is mined from soil deposits in lakes, estuaries and the sea to make bricks.
Organic and Mineral
The best clays contain alumina and silica, and compounds of lime, magnesia and ferric oxide. Immediately, we recognise the “white and chalky” clays that Vitruvius lauded, lime being prinicipally calcium carbonate, and the “red” clay, ferric oxide being a reddish compound. In short, the best clays are composed of a balance of minerals and organic deposits. In his text, Vitruvius warns against making bricks in the summer: “The fierce heat of the sun bakes their surfaces and makes the brick seem dry, while inside it is not dry.” Bricks, he writes, should be made in the spring or autumn.
Firing the Bricks
Vitruvius goes on to describe the havoc caused by building with undried bricks, and recommends that builders leave the bricks to dry for at least two years, ideally five years. Today, the season is not a concern. The clay units are molded on a industrical scale, dried on racks for three days, and fired for four days in thermostatically-controlled kilns. After baking, they cool down for five days more. Without such a process, our built environment would look quite different.
Backwards and Forwards
We have other building materials, of course: panes of glass, sheets of aluminium, slabs of concrete – but aren’t even these a kind of large brick? My favourite speculation is to look back into the past and try to imagine a world where the Sumerians had access to the same blocks of stone as the Egyptians, ignored their wealth of mud, and so were less fortuitous in another development that advanced human thought and the world with it. I mean of course, the inscription.