When we think of historically significant construction materials, stone is at the top of the list. From Stonehenge to the Taj Mahal, some of the world’s most celebrated and historical structures are made of stone.
But according to Dr. Emanuela Del Gado, a theoretical physicist at Georgetown University who studies materials’ structural and dynamic complexity, stone’s historical importance shouldn’t diminish its usefulness in modern construction. With unrivaled durability and unique properties, stone can still be valuable for contemporary builders.
A historically important material
Stone’s prevalence in historical construction is connected to the history of building technology around the globe, when the material was valued for its ability to keep interior spaces cool through the long, hot summers.
“In the Mediterranean, there are a lot of stone made buildings from the Greek and Roman periods,” Del Gado said. “You still see these buildings being used in South Italy where I’m from, as well as Spain, France and many other places.”
The fact that these buildings—many of them thousands of years old—are still standing and functioning, exemplifies stone’s unrivaled durability. “Traditionally, the historical buildings are typically made by using big pieces of stone,” Del Gado said. “The aesthetics of building with a large slab of stone is part of a tradition and has a cultural value. There is also all the craftsmanship that comes with making buildings with the stone.”
However, these values ultimately started to shift with new technology. “Cement production started during the Industrial Revolution,” Del Gado said. “And it was revolutionary, because this was a building material that is nearly as strong as the strongest stone, but with ingredients that are everywhere on earth.”
The increasing popularity of cement, which is used to make concrete, the world’s most-used building material due to its affordability and stylistic flexibility, led to a change in the way stone was used—from the core material of building projects to a new approach that used small pieces of stone to cover a building’s exterior.
“Stone facing solved the problem of providing the same aesthetic value and protecting the building with the quality of the stone,” Del Gado said.
The environmental benefits of stone
One of the chief environmental benefits of stone is how little must be done to it in the processing stages. “Stone doesn’t have the issues that cement has for concrete, because it’s a material that is widely available,” Del Gado said. “You need to do less to make it usable for construction. From that perspective, it is more sustainable.”
Moreover, stone is an abundant natural resource, requires almost no chemicals to maintain and emits zero hazardous pollutants, according to Jeanette Popiel, a Bluebeam product manager and former architect. Sone will also outlive most other structures built today, she said.
While concrete is the most-common building material today, it is also one of the least environmentally sustainable, as it is one of the primary producers of greenhouse gasses.
The insulator-like qualities of stone that made it so effective in keeping ancient buildings cool still have value today, reducing the necessity of air conditioning and other cooling technologies in warmer climates.
“We all have experience of the fact that stone houses are actually pretty good in the summer because the houses are fresher,” Del Gado said. “Stone is a material that is ideally suited to certain climate conditions, which is an issue for continuously changing climate becoming so extreme in certain areas of the planet.”
As summers grow warmer around the world, stone provides a surprisingly effective cooling solution, while requiring no additional energy and producing no additional waste.
Stone’s unique durability means that the environmental costs of using it in construction are spread out over a long period of use. “Durability is certainly one aspect that also enters the question of sustainability,” Del Gado said. “How long is a building with stone is going to last? And we have demonstrations of buildings that have lasted quite some time. So that is an aspect that should be considered in the balance of sustainability.”
Taking a local approach
Ultimately, stone is most effective when it can be sourced locally and applied effectively to local environmental conditions. “Stone construction is going to see growth in the areas where it’s readily available,” Del Gado said. “When you start thinking in terms of sustainable construction, we think of more and more trying to use local resources and materials that have a more sustainable impact.”
Stone has a place in today’s construction industry as it begins to be more responsive to the built and natural environment in planning and executing new designs.
“In the past, the mentality was that there should be only one material that works for every type of construction,” Del Gado said. “But, in fact, I think that the future of construction is trying to find custom solutions for each project, depending on where you’re building and what the building will be used for. Being able to diversify how we look into this problem and how these decisions are made would allow us to improve sustainability.”