It’s no secret that climate change and protecting the environment are on the minds of many these days. This is reinforced by the increasing amount of situations and people that are being directly affected due to environmental changes. To that end, potential homeowners are actively searching for homes that will have less of an impact on the environment, and homebuilders are investing in creating more ecological homes by incorporating recycled materials into the homebuilding process.
Common Recycled Building Materials
When homes are torn down, materials that are left over at the site are commonly referred to as C&D, or construction and demolition. The bulk of these materials includes drywall, asphalt, concrete, wood, shingles, and metal. According to the Construction and Demolition Recycling Association (CDRA), 583 million tons of this kind of debris are collected annually at sites across the United States.
Concrete is a primary element of home construction and is made with an aggregate and Portland cement. The aggregate is often sand or gravel, and the cement, usually in powder form, acts as a binding agent when mixed with water. According to a report from QY Research, the global ready-mix concrete market is projected to hit $624 billion by the year 2025. This might be in jeopardy, however, because sand — the most common aggregate — is being harvested to a point where observers feel it might not continue to be a renewable resource in the future. Asphalt, which is used in roofing and sealing for home construction, also faces sourcing issues. Asphalt concrete is a combination of bitumen which is a viscous, semi-solid form of petroleum and an aggregate which can be stone, sand or gravel. The ratio that makes up the asphalt concrete used in the U.S. is 5% asphalt and 95% aggregate and in this form it’s used as for road construction. The bitumen itself is used for the aforementioned roofing and sealing in home construction.
Drywall, also known by the brand name Sheetrock, is composed of the mineral gypsum. The sulfates from drywall that are left at C&D sites can leach out if the drywall gets wet and, in turn, can contaminate groundwater in the area. Dissolved sulfates can also convert to hydrogen sulfides, which give off a nasty odor of rotten eggs.
Wood has been estimated to make up 40 percent of what can be found at C&D sites and at times is broken down into the traditional lumber along with plywood, treated wood and composite wood paneling.
How These Building Materials Are Recycled
The push for a greener outlook in home construction has grown significantly, with an eye toward a reduction in water and energy use, along with the conservation of natural resources. Green building is also catching on because of the financial benefits for those builders who seek to limit their costs as well as to put themselves in line for LEED (Leadership in Energy and Environmental Design) certification through groups such as the U.S. Green Building Council.
Each common building material has a distinct process for how it is recycled. Concrete is recycled through crushing, then screening to sort out fine materials and plastic and dirt. The remainder is then further screened through water flotation, separators and hand sorting. The gypsum in drywall can be used for compost and also to create Portland cement. The scraps left over from drywall are used to make new drywall. Wood that’s untreated and clean can be turned into lumber or ground down to make mulch and engineered board. Asphalt recycling is actually a brisk business, with pavement and shingles being crushed down to create hot-mix asphalt that’s ready for use at construction sites.
How Builders Can Obtain Recycled Materials
These days, homebuilders have more options to obtain recycled materials for their projects. They can consult with local boards and groups on where to find C&D recycler companies in their area. The CDRA also has a listing available, and the National Demolition Association runs a recycling landfill directory. Once a builder locates a recycling center, they can make arrangements to obtain the materials for their homebuilding projects based on need.
The financial benefits of using recycled materials is two-fold. It allows builders to reduce costs in disposing of C&D waste, which can add to their budget. And more state and local governments are offering financial incentives in the form of tax benefits for homeowners who have energy-saving elements on their property. Homebuyers who are aware of these benefits will seek out dwellings that have these improvements already in place. Buyers and builders can find information on the financial
incentives of constructing homes with recycled building materials on the Small Business Administration’s website as well as the website of the National Association of Energy Service Companies.
Lastly, zero net energy buildings, which is another way that green building is expanding, are beginning to incorporate recycled materials in their construction, in addition to the use of solar and LED technologies.
Zero net energy buildings are structures where the total amount of energy used in the building equals the amount of renewable energy that is produced on-site. These buildings contribute less greenhouse gases to the atmosphere and reduce their usage of fossil fuels. California is leading the way by mandating that all residential construction in the state must be zero net energy compliant in 2020.
As more homeowners and homebuilders embrace the use of recycled materials for their abodes, the hope is that there will be greater accessibility to these materials and that the processes behind them can achieve an industry standard that will benefit everyone — and the environment — in the long run.
Christopher Smith is a freelance writer when he’s not sampling the best cuisine in his hometown of New York City. Prior to that, he worked in film and television post-production, and counts the honor of working with Eartha Kitt among his milestones.