– Old materials, new tricks
Any building, no matter its size, must strike a balance between construction costs and design. Architects constantly have to adapt their work to fit the budget they have available, the looks they want to achieve, and the use of the structure will see. The choice of materials, consequently, is not just a matter or aesthetics, but of what is within reach.
For many years, engineers and architects designed and built based on two variables, available budget and maintenance costs. The former was a given, the later was dependent on the building’s purpose and time horizon. When considering upkeep costs, however, builders focused on issues like roof replacement, how long windows, electric wiring or sidings could go without being replaced, or when the owner would need to repave the driveway. In a world with cheap plentiful fossil fuel, energy costs were rarely part of the equation.
For modern buildings, however, that careless attitude towards energy use is no longer acceptable. Not only energy costs have risen, but we are now well aware of the consequences of excessive emissions and the need to move towards carbon neutrality. Architects and policy makers have realized the significant impact that buildings have on the environment; 40 percent of all greenhouse emissions are produced by the building we use to live and work. As a result, we now try to strike a balance between costs, energy use, and design, adding a new layer of complexity to the equation.
This new equilibrium has forced engineers and developers to look for new ideas to make buildings more efficient. Some have resorted to innovative, exotic materials or new designs, using the latest technology to reduce emissions. Others have sought inspiration looking to the recent past, finding ways to repurpose traditional building techniques and materials to cut energy use.
There is a wisdom in looking at the past. Before the industrial era, builders had to find ways to create structures that were usable without access to copious amounts of energy. Houses could not rely on just burning lots of oil to stay warm in the winter or consume megawatts of electricity for cooling during the summer. Natural light was a priority. Buildings had to be energy efficient because energy was scarce and expensive. Centuries of trial and error led to structures that had the wisdom of experience in them. As a result, many traditional building techniques and materials are remarkably efficient at conserving heat
while remaining cheap regarding construction costs.
The most traditional of all construction materials is undoubtedly wood. Easily available in hundreds if not thousands of varieties almost anywhere in the world, wood had been largely relegated to small, temporary structures or single-family housing. Architects and engineers saw it as a lightweight, cheap, easy to assemble material good for quick construction and utilitarian buildings, not something apt for complex structures.
In recent years, however, many builders are starting to see wood in a new light. For starters, the overall carbon footprint of producing lumber for construction is much lower than concrete or steel, as it requires much less processing before use. Wood is a renewable resource, and with good forestry management practices, it is in fact a net carbon sink.
Besides its reduced cost and environmental footprint, wood has some remarkable properties as a material. It is lightweight, outperforms even steel on tensile strength, is naturally sound absorbent and has a higher insulation rating than steel or plastic. It also has the advantage of being much more aesthetically pleasant than concrete or steel, thanks to the infinite variety of types and textures available.
Most remarkably, engineers are realizing that wood is a viable material for larger structures, including large multistory buildings. Cities like Vienna, Paris, and Berlin have started experimenting with wood skyscrapers, apartment and office buildings more than 80 meters and 18 floors tall. In Japan, engineers have long known that wood structures, thanks to their structural flexibility, fare better in earthquakes. In the US, developers have adopted the four-story stick-frame apartment building to produce affordable, energy-efficient, dense buildings, instead of more expensive and less efficient concrete and steel
Engineers are revisiting other traditional materials, as well. Bamboo has become popular for walls and flooring, as it shares many of the virtues of wood (cheap, light, good insulator) with the added advantage of being extremely fast growing, making it even more sustainable. Wool, another natural, fast-growing material, is an extraordinarily effective insulator, as anyone that has a wool sweater can attest. It is now being used as such in walls, ceilings and attics. Cork has also seen a resurgence; thanks to its resilience and flexibility, it is an excellent insulator and sound absorber, especially useful for flooring.
Traditional building techniques also have attracted attention. Adobe and other traditional brick-making materials might be heavier and less flexible than concrete but are extremely good insulators. Adobe buildings remain cool during the summer and retain heat effectively during the winter while being extremely cheap to produce and maintain. Cob, a mixture of clay earth, sand, and straw, is extremely resilient and can last for centuries if well maintained; as it is breathable, it stores heat during the day, making it self-regulating. Architects are also learning from traditional building shapes and forms, on how patios, fountains, colors, windows, and lights can be used to control and regulate temperatures. This has led to the re-adoption of modernized version of traditional housing designs in many regions, as they have proven more resilient and effective than more modern designs.
The most important outcome of these innovations, however, often goes beyond energy use or environmental impacts. Traditional building materials are uniquely attuned to how we live a who we are. Wood, brick, bamboo, have a rough, imperfect, organic warmth that gives buildings a sense of place absent in more polished, newer materials. They also remind us on who we are and where we come from, on how we have lived and thrived for generations. Wood, adobe, brick or cob might be more efficient, clean, affordable, sure, but they are also a powerful link to our collective past.
Johnson Controls-Hitachi Air Conditioning, Communications