How sustainable are building materials?
The greenhouse gas emissions are the main culprit of the so called ‘greenhouse effect” and the climate change. Who to blame for these excessive carbon dioxide (greenhouse gas) emissions? Most people immediately think of industry as the biggest polluter, but the statistics discovers a different picture. Although these harmful gasses are emitted through transport, industry, production of fuels, deforestation and many other activities, buildings where we live and work are the largest contributors to the world’s pollution. They account for approximately 40 percent of carbon emissions, whereas transport and industry account for 33 and 29 percent, respectively.
The main reason for these high numbers is buildings’ immense electricity consumption (energy spent for cooling, heating and lighting) and other indirect emissions (management of waste, water use, leaks from refrigerants etc.). Also, the construction, operation and the poor choice of building materials are another reason why our homes and offices are the world’s largest polluters. Energy that’s consumed during the building’s life accounts for most of the carbon emissions and just a small percent is associated with the materials used in construction. However, using the sustainable, eco-friendly materials is extremely helpful in reducing the buildings’ carbon footprint.
Several things help making a building “green”: sustainable materials used in construction and furnishings, energy-saving appliances, solar panels, passive solar design, green roofs and so on. The most important benefits include extended building lifespan, conserving energy and saving money in the long run, improved home air quality and occupants’ health, minimized waste, supporting local builders and increased resale value. Using environmentally sustainable materials is perhaps the easiest way of applying green principles in construction. However, it’s good to weigh prices and benefits for both people and the environment before deciding on the material that will be used.
Concrete is the most used man-made construction material. Unfortunately, it’s the material which production has a great impact on the environment and it’s highly energy-consuming. However, there are sustainable forms of concrete –mixed with recycled and waste materials such as glass and wood chips. Also, when used responsibly, concrete is a great material for creating thermal mass which regulates home’s temperature and enables a passive solar design. Most importantly, concrete meets some other requirements of sustainable construction: it maximizes buildings durability and has low maintenance costs.
Steel is another “unexpected” sustainable material. You can’t build the walls out of steel, but the steel frames are one of the best ways to increase the durability and sustainability of your home. The steel industry has reduced the amount of energy used for production and the steel usually includes recycled materials as well. It’s strong, safe and not affected by common issues such as rats, termites and mold. The steel won’t deform over time and less resources are required in construction. Homes with steel frames are resilient, beautiful and built to last, and with the improvements in the steel industry, this material can definitely be considered as sustainable.
Although wood is generally thought to be a “green” construction material, it’s not necessarily so. Different types of wood have different carbon footprints. When buying wood, several things should be taken into account. The most important is whether the wood was grown in sustainably managed forest. It’s always better to use locally sourced materials and the same goes for the wood. For example, the hardwoods that are generally considered as the most sustainable in the US are white ash, black cherry, mahogany, maple and oak. However, fast growing trees are becoming more and more popular – bamboo and cork are the fast-growing trees usually used for flooring.
Finally, some of the best and the most cost-effective sustainable materials that are getting increasingly popular are straw bale and rammed earth. Their greatest benefit is the fact that the material is abundant and cheap. Sometimes, cement is added to earth to increase the durability and this is called “stabilized rammed earth”. The only challenge in this method of construction is that it needs an experienced builder. However, the benefits are huge as it has huge thermal mass potential when used in the right climate. Straw bale has been used as construction material for centuries and if you combine it with plaster walls and cement, it can last forever.