Building Materials: Concrete under our Feet


Do you have concrete in your life?  Sure you do.  You see it in the sidewalk but you may not notice it in the foundation of whatever building you’re currently standing in. Concrete pretty much completely surrounds and supports our modern life.  

How Does Concrete Work?

Concrete starts out as a pour-able slurry and then hardens into a rock like solid.  We take advantage of that quality to spread it out between markers to form sidewalks and floors and to pour it into deep channels to form walls.

Modern concrete is a combination of aggregate, cement and water.  Portland cement, the binding agent in concrete, is made up of lime silica, iron oxide and lumina. The aggregate is sand, gravel or even rather large rocks, depending on the application and it makes up 75% of the volume of normal concrete construction.  Water is water.

concrete aggregate

Take care of the concrete in your life 

While it is amazingly strong, and pretty durable under the right circumstances, this material does need good maintenance to keep it up.  It’s important to protect it from water getting in the cracks – especially in parts of the world with a freeze-thaw cycle. That’s as true when talking about leaks in your basement wall or repairing America’s network of concrete roads and bridges.

We’ve linked before to this hilarious faux trailer produced by John Oliver’s Last Week Tonight which frames deteriorating national infrastructure as the Next Big Disaster Movie and profiles the heroes who protect us all by meticulously inspecting, repairing and sealing.

The History/Mystery of Roman Concrete

Roman concrete is not the same as the type we use today and we don’t know the formula that they used.  We are sure it made use of volcanic ash – think Pompeii – there were some active volcanoes around in Roman times, but we can’t identify the other key differences.  And yet, it performs much better than modern concrete does.


The Pantheon, for example, remains the largest unreinforced concrete dome ever built – 142 feet wide and with a 27 foot oculus at the apex.  Whatever the reason, Roman structures like the Coliseum and the Pantheon have survived more than two millennia, often with no maintenance.  We can’t say the same about our modern product.

More Recent History

Despite not being QUITE as amazing as the stuff the Romans built with, modern concrete is used in so many aspects of modern life.  Engineers in England started trying to work with concrete during the late 18th Century. The 1867 patent for reinforced concrete – combining the strength (under compression pressure) of concrete with the strength (in tension) of metal – is the lynchpin of our modern usage and, from there, the idea took off like crazy.

Concrete became particularly popular with the international Modernists.  To single out one example, Le Corbusier was well known for his love of concrete construction both because it was relatively cheap and almost infinitely pliable into the unique shapes he designed.  He used it in houses (Villa Savoye), a monastery (La Tourette) and church (Ronchamp).

unite dhabitation

During the construction of the Unite d’Habitation (above), difficulties with contractors led him to leave off a plaster finish and use the exposed concrete surface as the finished exterior of the building.  He called this idea beton brute, or bare concrete and many credit it as the foundation of brutalism.

Brutalism became popular with a certain school of architects between 1950 and 1970, especially for government and university buildings.  It worked as a sort of take-no-prisoners anti-style that rejected the more mannered designs of previous eras.  Unfortunately, it immediately became hugely UNpopular with just about everyone else.  Brutalist public buildings that still exist are probably just waiting until someone can afford to tear them down.

This bad press naturally made some negative associations for the building material.  Despite some ill fated PR attempts – check out this crazy pamphlet advertising entirely concrete homes for the middle class from the 1940s’ – the industry mostly took their product underground.  Architects still use A LOT of concrete but tend to hide in the hidden skeleton of buildings.

Let Your (polished) Concrete Shine

Moss, on the other hand, really doesn’t object to exposing the concrete part of buildings, on occasion.  A polished concrete floor, for example, can be a beautiful finish material and is also a very functional and cost effeective one.  We like to celebrate the concrete that is all around us.  However, we wouldn’t recommend building a house entirely from exposed concrete.  Instead we like to use it in contrast with an array of other materials like exposed brick, shiny clean tile and touchable reclaimed wood surfaces.

Today, we give a little “thank you” to all the concrete surfaces and masses that literally underpin our modern life.  Cheers, concrete!