What Building Material (wood, steel, concrete) Has The Smallest Overall Environment Impact?

Wood is a fundamental part of construction. It is a versatile construction material because it can be found everywhere. Early settlers in North America used wood to build log cabins since it was more efficient than transporting other materials all the way from Europe. (Rosmanitz, 2013) Wood did not require extensive tools in order to be produced as a construction material. Back then wood was the most reliable building material available. Wood is so reliable that houses built over 800 years ago are still standing today (Hoibo, Hansen, & Nybakk, 2015). Looking over the course of time, wood is still the preferred method when constructing houses today. However, after some time a new material became available. Concrete has been used in several ancient civilizations namely Rome and Egypt, where resources are scarce and wood could not be found. We see concrete used today mostly in basements, bridges and in large industrial structures because out of most materials, it is one of the most impermeable and cost effective.

Looking around, you can argue that the most commonly used building materials in construction today consists of concrete and steel. Unlike wood however, concrete is made through unsustainable practices. Wood can be torn down to be reused, but concrete cannot be salvaged and it is left where it is demolished. Steel is the newest of the three materials. Steel became a popular building material during the industrial revolution due to its durability. During this time, most people began switching from building with wood to steel. With society’s current knowledge, we know that wood is the best option in terms of sustainability. The progression of concrete and steel may not lead down the most sustainable path.

Given the compelling threats of global climate change, sustainable construction is the way forward for the building industry to play its part towards achieving a sustainable and healthier world. One can simply define sustainability as building to meet the needs of the present generation without compromising the ability of future generations to meet their needs. Scientists and experts agree that human activities are contributing to climate change. Only recently has the reality of ecological disaster due to human’s unnatural involvement with the environment become more apparent. One specific percentage of involvement is the construction industry. Estimately, buildings contribute as much as one third of total global greenhouse gas emissions, primarily through the use of fossil fuels during their operational phase (Huovila, Ala-Juusela, Melchert, & Pouffary, 2009). Excessive carbon emissions are a real threat to the world and could cause major problems down the road. In North America alone, the building sector accounts for about 37% of Carbon dioxide (CO²) and 40% in Europe and this is likely to continue in the ensuing years (Beyer, 2012).  Additionally, if we continue to build with unsustainable materials, eventually we will run out of materials to build with. The tipping point is rapidly approaching, where the world runs out of resources and energy. This cause and effect relationship will not only affect the current generation, but every generation that comes after will have to deal with the problems created. However, if building sustainably and ecofriendly desired targets are to be met, the building industry has to tackle emissions from the Building Sector with much greater seriousness.

Aciu (2014) explains that the entire lifecycle of a building impacts the environment. This is assessed by a functional tool called Life Cycle Assessment (LCA) or cradle-to-grave approach. LCA is used to perform an assessment in which the materials, construction, use, and demolition of a building are quantified into embodied energy and carbon dioxide equivalents, along with representation of resource consumption and released emissions. These results are useful to architects, structural engineers, contractors, and owners interested in predicting environmental impacts throughout a structure’s life. The life cycles of building materials must be better understood before their environmental impact can be reduced and LCA have been an efficient tool in answering important questions about current topics of concern to the public, such as greenhouse gas emissions (Hsu, 2010).

The manufacture, transport, and installation of a building materials such as steel and concrete require a large quantity of energy, despite them representing a minimal part of the ultimate cost in the building as a whole. Experts refer to the energy consumed by all the processes as Embodied Energy (EE) (Høibø et al, 2015). The small amount of embodied energy (carbon) in one ton of concrete, when multiplied by the huge amount of concrete used, results in concrete being the material that contains the greatest amount of carbon in the world. The EE of concrete, which is the highest, is 12.5MJ/kg EE, steel is 10.5MJ/kg EE and the lowest is wood with 2.00MJ/kg EE. (Hsu, 2010).  The Embodied energy content of each building material varies enormously, especially concrete because cement production is extremely energy and fossil fuel intensive, making it a ranking producer of carbon dioxide emissions contributing to global warming (Shams et al, 2011).

Considering the Embodied Energy of concrete and steel, it concludes that their environmental impacts are dramatically heavy. On the other hand, from a carbon footprint perspective, wood buildings require less energy from resource extraction through manufacturing, distribution, use and end-of-life disposal, and are responsible for far less greenhouse gas emissions, air pollution and water pollution. Shams et al. (2011) compared El Dorado High School in Arkansas built of wood to other buildings built with steel or concrete.  The authors discovered that the wood building’s sustainable design and construction also called green building approximately consists of 153,140 cubic feet of lumber, panels and engineered wood can be compared to 2,184 cars off the road for a year. For this volume of wood, ASTF (Alliance for Saving Forests) suggests forests grow this much wood in 13 minutes and the carbon sequestered in the wood is approximately 3,660 metric tons of CO²   and more significantly the avoided greenhouse gas emissions 7,780 metric tons of CO² . This confirms wood is the best renewable, biodegradable, non-toxic, and energy efficient building material. In response, wood has gotten a practical boost from governments and industry in timber rich places like Austria, Scandinavia, and recently the US Department of Agriculture launched a competition for wooden high-rise designs and announced a $1 million investment to train architects and builders to work with wood (Humphries, 2015).

Often, experts take into account the production of a building material into account when talking on factors that focus on sustainability. Using the LCA, this factor is assessed. Some building materials such as steel are more difficult to create, and as essentially nonrenewable resources they contribute more to total material consumption (Kim et al, 1998). Steel is the newest of the three materials. Steel became a popular building material during the industrial revolution due to its durability. During this time, most people began switching from building with wood to steel. Unfortunately, back then the harmfulness of its manufacture was not known. The production of steel, cement, and glass requires temperatures of up to 3,500 degrees Fahrenheit, which is achieved with large amounts of fossil fuel-based energy. Wood, on the other hand, is made using energy from the sun (Shams, Mahmud, & Amin 2011). Making a switch from unsustainable building materials like concrete and steel, to sustainable building materials like wood, in office and commercial buildings, can substantially help reduce the negative impact building has on the environment.

Further addressing the production of building materials, wood has one great ecological advantage over steel and concrete. Wood is a truly natural material and has the ability to regrow and reproduce. Trees can be harvested just like any crop and easily turned into framework. Tree farms are an available option for mass producing structural material. They are capable of being efficient and sustainable, however they are not required to follow any sort of sustainability laws. This is unfortunate, but with the implementation of new laws we can make the most sustainable material even more sustainable. We could make it required by law to be certified by the American Tree Farm System. If it is required than there are no more excuses of why wood is not the most sustainable material. (Standards for Certification, 2016)

To be certified by the American Tree Farm System, there are eight standards that need to be followed. The first standard is a commitment to practicing sustainable forestry. One-way tree farmers can do this is by developing a forest management plan and implementing sustainable practices. The second standard is compliance with laws. This standard simply requires the landowner to follow all relevant regulations. The third standard is reforestation and afforestation landowner. Standard four is called air, water, and soil protection. This standard is sustainable because it requires the landowner to maintain or enhance the land quality. The fifth standard is the health of your woods and the animals that call it home. The sixth standard is forest aesthetics.  The seventh standard is protecting special sites. Special sites need to have historical, archaeological, cultural, geological, biological, or ecological characteristics. The last standard, standard eight, is, forest product harvests and other activities. These are the eight standards that you need to follow to be a certified by the American Tree Farm System (Standards for Certification, 2016). All of the standards prove to the public that even those these tree farms are being used for material purposes they are still contributing to the ecological health of the area. The farms will have a constant presence of possibly 50 to 80 years. That amount of time solidifies a constant income and in so protect that area from further development. The world will benefit much more from a forest that makes money then a power plant that makes money. Having this balance of industrialization and forest health creates a very sustainable system.

The second major point to the energy cost of a building material is its breakdown. If a material is not able to be efficiently recycled, then it does not prove to be sustainable. When we break down concrete, it is impossible to be reused for construction again. Steel requires a massive amount of energy in order to heat up the steel in order to melt into a new material. Every time steel is recycled, the steel has to be melted at high temperatures in order to be turned into new material. The energy required to recycle steel requires energy which comes from fossil fuels. Reusing steel still hurts the environment. Wood is a material that requires little energy to be salvaged and can easily be used for construction. Reclaimed wood, the term that is used for extracted lumber from old structures, can be extracted underwater if the wood has not rotted away. [BJ1] One of the benefits of using reclaimed wood instead of fresh new wood gives us an opportunity to use larger pieces of lumber where new wood cannot be grown as tall due to time. New wood also needs time to shrink into its size when it begins to dry out, as long as reclaimed wood has not rotten, it can be far more reliable than new wood (Erhlich, 2011).

Reclaimed wood not only reduces the carbon footprint for construction, it is also economically cheaper] than buying new wood that costs money to plant and grow. The market for recycled building materials is cheaper than buying brand new. Reclaimed wood has given people opportunity to create their own jobs and a new market. People search for companies that specialize in taking wood and contact them in order to dispose of the material (Martin, E., & Schendel, E., 2014). Everyday there are new buildings being constructed and old buildings being torn down. Because of this, people are always searching to dispose of old materials like wood. Not all of the material can be salvaged but a little comes a long way. (Martin, E., & Schendel, E., 2014) Having the option of constantly recycling and reusing materials creates a long lasting cycle. Less trees are needed, landfills will not be filled with perfectly reusable wood, and it will be cheaper for the consumer because they cost of labor will be much less.

Even though wood has the ecological benefits over other materials it is still not being used to the amount it should. At the moment there are however, some people who are pushing to get green building moving forward. The nonprofits U.S. Green Building Council (USGBC) developed LEED, or the Leadership in Energy and Environmental Design, in March, 2000.  What this means is that to become LEED certified, a builder must be environmentally responsible and use resources efficiency. They have applied their standards on over 83 thousand projects worldwide. (LEED, 2016)

One thing that LEED certification requires is low embodied energy of the project. Embodied energy is the total amount of energy it takes to get materials to the job site. If we are talking about wood this includes the gas it takes to run the chainsaws, transportation to the mill/job site, and also the energy it takes to cut the timber and turn it into framing material. To be LEED certified you need to take into account how far away the supplier is. If the price of wood is cheaper at a supplier 100 miles away compared to a supplier 10 miles away LEED will still require you to use the closest one to keep the embodied energy down (LEED, 2016). LEED’s system effectively promotes green building and the construction of sustainable infrastructure.

The studies and examples throughout the paper show that wood is ultimately the most sustainable product for construction. Wood is reusable and clean to make into a building material. Forest farms could help counteract the growing deforestation problem. Society needs to switch from building with mostly concrete and steel to mostly with wood. To do this, the government should provide incentives for sustainable materials. Nothing is going to get accomplished until specific rules are set in place and contractors are rewarded for meeting sustainability requirements. Incentives can include certifications and tax reductions. The main point to make is to drop the cost of sustainability and increase the cost of unsustainability. Simply initiating positive rewards for using wood society could continue on a long tradition of using wood as the most common building material.

A certification provides considerable incentives for sustainable building. Adding a LEED award to a building stamps a great marketing tool on its resumé. These awards allow contractors to find more clients. The added fact that they are green buildings makes them stand out in the general pool of construction, which makes it investment worthy.  Vierra’s (2014) study finds that sustainable building creates larger investor pools, saves money by decreasing the energy spent to create it, and even comes with the added benefit of tax credits. Sustainable buildings are shown to see an increase of up to 6.6% on return investment. Certified construction also has seen a 3.5% increase in occupancy and a 3% increase in rent (Vierra, 2014). Construction is a business and a business runs on income. Getting certified increases the amount of buyers and so increases the amount of income, and this alone should be a major push to get more contractors building sustainably.

In the United States there are federal tax credits given to company structures made with low energy materials. As long as the structure is deemed energy efficient there are multiple tax credits available to the contractor and buyer. Incentivising green construction with the promise of lessening the cost is one of the best ways to change a tradition. (Vierra, 2014) For example, the Energy Policy Act of 2005 contains the Business Income Tax Deduction. This tax deduction can reduce up to $1.80 per square foot if the business is using energy efficient equipment or materials (DiPeso, 2007). In the long run this could save businesses an incredible amount of money. The best and most effective way to change the construction industry is to create a system that ultimately rules out unsustainable building materials. By creating more tax credits and more regulations for green building, construction can begin to move forward towards a future of solely sustainability.

Unsustainable building negatively impacts the environment however, switching from building materials like concrete and steel, to sustainable building materials like wood, in office and commercial buildings moves the construction industry towards a healthier world. In the past concrete and steel stole the spotlight for most innovative building materials. During the industrial revolution and until now, big grey buildings were the staple of civilization and progress. From the studies shown, that is not the case anymore. These benefits have initiated programs such as LEED and ATFS. They are a great starting point towards sustainability. They provide ground rules and set the model of green building and management. LEED and ATFS are important stepping stones, however, more certifications need to be made and stronger rewards need to be given. Green building is used as a bragging point of modern infrastructure, but it is not the most commonly used method.  With more incentives the status quo of building can begin to progress forward.

References

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Beyer, G. (2012). Wood and climate change. Tackle Climate Change. Retrieved from http://www.cei-bois.org/files/BuildWithWood.PDF

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Martin, E. & Schendel, E. (2014, May 7). Making a living selling reclaimed wood. SW News. Retrieved from http://www.swnews4u.com/archives/21450/

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