Construction and demolition waste constitutes almost half of the total solid waste stream in the United States. However, there are much better alternatives than classifying items as waste, and there are many ways to reduce the environmental harm associated with materials. Using fewer materials, choosing environmentally preferable materials, using locally harvested materials, and eliminating waste all provide great benefits.
A systems-based, life-cycle perspective and an integrative process will help project teams achieve their goals when addressing the use of materials and resources. Life-cycle assessment will also serve as a great tool to evaluate materials and resources according to their environmental performances.
Life-cycle assessment, which examines all the environmental effects of a product (or even a building) quantitatively during an entire life cycle, can allow project teams to see the background of the building products. A cradle-to-grave approach, and, even further, a cradle-to-cradle approach, is used in LCA, allowing both the total energy use and other environmental consequences resulting from the creation of that material to be calculated.
The benefits of conducting an LCA can be to see the trade-offs between different materials and to select the materials that would be the best fit for the project and the environment. Instead, the project teams may decide not to use some materials and reduce the total amount of materials in the building, which is also called dematerialization.
The conservation of materials starts by eliminating the need for materials during the planning and design phases. Rightsizing the project is the first step toward conservation of materials. An example of rightsizing includes designing buildings that are not larger than really needed and will therefore require fewer materials and resources. The same logic also applies to neighborhoods, as denser and more compact mixed-use neighborhoods will require fewer miles of roads and less infrastructure.
Reusing existing materials, salvaged materials, and especially existing buildings results in tremendous material savings. If the project is a major renovation of an existing building, the project team should look for ways to reuse the following existing materials such as framing, envelopes, walls, flooring, ceilings, and roofing. Using salvaged materials will contribute to reduction in the demand for virgin materials.
Adaptive reuse strategies, which can also be called “designing for flexibility,” should be well considered in the buildings that may need frequent changes in layouts or floor plans. For example, a flexible floor plan for a hospital building can allow simple changes to be made regarding the sizes of rooms due to the changes in medical equipment that occur alongside the rapid evolution of the technology. Through the use of movable wall partitions or the use of modular systems, the layout of the hospital plans can be changed without going into a complete renovation.
According to the EPA, the best way to eliminate waste is through source reduction. Source reduction refers to the exact sizing of the materials to be produced through prefabrication, modular construction, or similar methods, so that no waste is generated on-site. Since it’s about decreasing the unnecessary material brought into a building, it also covers the use of products with less packaging.
The conservation of materials does not end with the completion of the construction phase. In a green building, the same principles should be applied throughout the building operations phase to the last phase of the building—a demolition or reuse phase.
When selecting materials to be used in the project, the project team should consider a material’s entire life cycle or life cycles since the aim of a sustainable material should be to have infinite life cycles. After the useful life of a material ends in one building, the material should be used as another product or a part of another product in order to continue being used. In other words, the first goal here is to implement all the strategies to stop the material from going to landfills as waste.
The second goal should be to evaluate the effects of a particular product on the environment. During their life cycles, all buildings and building materials have different impacts on the environment. The building materials are harvested/extracted, manufactured in the factories, and then installed in the buildings to be used. After that, they either get demolished, disposed, or recycled. Energy is also consumed during each of these stages.
In addition, the way that manufacturers, contractors, or individuals manage each of these steps will vary for each manufacturer, contractor, or consumer. Materials that get extracted or harvested in a sourceful manner, get manufactured in environmentally friendly facilities, and can be recycled to be a part of another product should be less harmful to the environment than regular products. Or, a product that requires lots of energy consumption for extraction and is also not very durable cannot be considered as environmentally friendly.
Using locally produced materials is another plus. An environmentally friendly recyclable material that was extracted in China, manufactured in Germany, and brought to the United States cannot be considered environmentally friendly after all the greenhouse gas emissions that occurred during transportation. Several credits under the Materials and Resources credit category in LEED (Building Product Disclosure and Optimization credits) provide a location valuation factor, which means that if the purchased products or materials are extracted, manufactured, and purchased within 100 miles (160 kilometers) of the project, LEED will award the project in the credit calculations by valuing those products at 200% of their cost.
Project teams should also be careful about greenwashing when selecting products, which refers to the presentation of a product or a material as being more environmentally friendly than it actually is. Environmentally preferable materials should provide accurate and transparent information and declarations to the buyers.
Let’s consider the Environmental Product Declaration (EPD), which looks at the entire life cycle of a product and assesses the cost of the product on the environment. Products that contain an EPD will give information about a product’s impact on global warming, ozone depletion, water pollution, greenhouse gas emissions, human toxicity, and more.
Furthermore, a product with a Health Product Declaration (HPD) will provide disclosure about its material ingredients, a list of potential chemicals, related concerns, and additional health information.
For manufacturers or raw material suppliers, Corporate Sustainability Reports (CSR) will provide information about the manufacturer or raw material supplier of a product that has been verified to employ sustainable principles during the creation of their products.
By considering products with transparent information and declarations, project teams can make better decisions.
The construction industry is responsible for the generation of huge amounts of waste. According to the EPA, in 1996, 136 million tons of construction and demolition debris were generated in the United States. In hindsight, it can be said that most of it could have been used in better ways.
Green building projects should work on reducing the amount of waste that goes to landfills. With the development and implementation of a waste management plan for both the construction and operation phases of a building, project teams can identify potential waste streams and also look for ways to reuse or recycle them. At a minimum, all the LEED projects must recycle paper, corrugated cardboard, glass, plastics, and metals during the building operations phase.
By also establishing sustainable purchasing program developing a sustainable material purchasing program, building users can choose environmentally friendly products when buying office papers, computers, furniture, light bulbs, and more.
In this century, there are many different ways to go green and there are also various green building rating systems to help project teams create green building projects. LEED, which is the most widely used green building rating system in the world, can be a great starting point for constructing a green building. LEED-certified buildings are proven to be environmentally friendly and to respect human health. However, there are other major benefits of a LEED certification that can be summarized as money savings over the lifetime of a project, increased project value, and increased building occupant satisfaction.
If you are in the design or construction industry, you can even think about earning a LEED credential to help other projects go green and enhance your career. All you need to do is study for your LEED exam and become a LEED Green Associate or a LEED Accredited Professional.
Author of LEED Complete Study Guides