Construction and demolition (C&D) waste is the wasted building materials and rubble generated during construction, remodeling, repair, and demolition of houses, commercial buildings, pavements, and similar man-made structures.[1] Construction and demolition waste consists of wood, metal, concrete, asphalt, tar and shingles, gypsum board and plaster, plastic, paper and cardboard, and other miscellaneous items. The term construction and demolition waste does not normally include hazardous waste, although hazardous waste does often come from the demolition process. According to the American Institute of Architects, construction and demolition waste makes up almost 40% of solid waste in US landfills.[2] With the advent of sustainability practices in the US, individuals, governments, and companies alike have taken greater interest in reducing and managing the waste generated in construction and demolition processes.

History


For most of history, humans have not produced enough waste to require management. Waste management has become increasingly important however, starting during the time of the Industrial Revolution. Historically, construction material prices were the limiting factor in building, not labor, so builders conserved material use wherever possible. Construction materials have become increasingly mass produced after World War II, resulting in cheap, high-quality, uniform materials. With access to cheap, high quality, uniform materials and ever-increasing labor prices, contractors became less concerned with conserving material and more interested in doing things quickly with minimal labor costs.[3]

In the US, the increase in waste production both in industry and municipalities resulted in government regulation of how waste is produced and disposed of. Congress passed the Solid Waste Disposal Act of 1965 in conjunction with the Clean Air Act, primarily because local governments were using open air burning to dispose of the majority of waste.[4] In 1976, Congress replaced the Solid Waste Disposal Act with the the Resource Conservation and Recovery Act, (RCRA), which required the EPA to regulate solid waste production and disposal.[5] Included in the solid waste regulation was construction and demolition waste. The EPA revised the RCRA in 1984 with the Hazardous and Solid Waste Amendments (HSWA). Both the RCRA and HSWA focused primarily on the regulation of landfills and the amount of hazardous waste they were allowed to accept and store.[6] The Resource Conservation and Recovery Act place the burden of regulation primarily with the states, who often in turn place it on more local levels of government such as counties.[7]

In the US, the Resource Conservation and Recovery Act is still the primary means of regulation for all types of waste, including construction and demolition waste. The Resource Conservation and Recovery Act primarily deals with regulating landfills, but it also promotes reducing waste and conserving the natural resources used.[8] In response to this increased regulation, governments, landfills, and waste management companies have built a pay structure that makes it expensive to simply dump waste and instead encourages alternate methods via recycling, reduction, and reuse of waste products.
LEED Certification Symbol
LEED Certification Symbol


In addition to the Resource Conservation and Recovery Act, the construction industry is often affected by Leadership in Energy and Environmental Design (LEED) certification. LEED Certification was created by the US Green Building Council and is a coveted award for new and existing buildings. One of the many ways that buildings earn LEED points and become LEED certified is through reuse and recycling of building materials.[9]



Methods


Disposal

The main methods of disposal before waste management was introduced were dumping and incineration. These two methods are still practiced today in much more controlled and environmentally friendly ways due to government regulation.
Construction and Demolition (C&D) Landfill
Construction and Demolition (C&D) Landfill


Landfills

Landfills are where large amounts of construction and demolition waste still end up. Because landfills are becoming increasingly regulated for air and water contamination and they have increased the tipping fees to dump at their locations, they are considered the last resort for waste disposal.[10]

Incineration

Some construction and demolition waste can be incinerated, primarily wood products. Incineration is not an ideal method of waste disposal, but it is often preferable to dumping in landfills. Incineration often releases harmful chemicals, so it must be carefully regulated. However, rather than simply dumping the waste, incineration can be used to convert the waste to energy.

Both methods of disposal are economically effective for the present, although increasing tipping fees are making them less economical. Disposal is still less time- and effort-intensive, but it is not environmentally responsible.

Diversion
Hierarchy of Waste Management
Hierarchy of Waste Management

A preferred method to simply disposing of the waste is called diversion. In diversion, waste is diverted from landfills in a several step process. The first step is usually to sort the waste by material so that it can be reused or recycled.[11] Construction waste materials can either be sorted at the job site, or it can be sent to a waste management facility to be sorted.[12] If the waste is sorted on site, the material can often be reused at the actual job. Waste that cannot be reused on site or that is sorted offsite is usually recycled into new material or reprocessed and remade into the original material. For example, clean wood products can be made into materials like particle board and engineered wood, or it can be ground up into mulch or burned for energy. Concrete rubble can be ground up for aggregate in new concrete. Asphalt shingles can be reprocessed and used for asphalt paving.[13] Materials than cannot be reused or recycled are then usually sent to the landfill.

Diversion is helpful in managing waste in a sustainable manner, but it takes more time and effort than disposal, and it is often not as economical in the short-term either.

Critical Path Method

The critical path method makes use of engineering and economics principles to reduce waste on the construction site and recycle necessary waste as much as possible. The critical path method operates on the idea that excessive waste is uneconomical to the contractor because the contractor paid for the material in the first place and also pays for the tipping fee to dispose of it.[14]

The critical path method consists of two steps.

Material Minimization

  • Build structures with dimensions that align with standard lumber sizes. For example, build a house that is 40 x 48 to minimize wasting oriented strand board, plywood, and gypsum board.[15]
  • Use offsite construction.
  • Ensure that sheathing is being used in a cost effective way and that no large pieces of oriented strand board are being wasted.
  • Use the Optimum Value Engineering method, which aligns rafters with studs and places them 24 in. on center, rather than 16 in. on center. The Optimum Value Engineering method uses a single top plate rather than a double top plate, all without sacrificing structural integrity.[16]
  • Sort scrap materials on site so that they can be reused.
  • Allow employees and the community to take scraps for reuse.[17]

Diversion

Diversion in the critical path method is similar to diversion described above, with one difference: the contractor becomes responsible for where the material is diverted.

The critical path method is useful for a larger company that is interested in seeing long term changes both environmentally and economically. It does take a large amount of time and effort on the part of management.

Deconstruction
An example of a home being deconstructed
An example of a home being deconstructed

Deconstruction is dismantling a building in a way that salvages the materials and allows them to be reused or recycled. It allows a building to be remodeled or torn down in a safe and environmentally friendly way, rather than simply gutting or demolishing the building. The process of deconstruction gives second lives to old building materials that have historic significance and it often saves the builder and owner money in tax breaks as well.[18]

Deconstruction is not for every project; some materials are very hard to reuse or recycle. Deconstruction also takes more time than standard demolition.


Examples


Aspen Ski Company
Elk Camp Restaurant, owned by the Aspen Ski Company and recipient of LEED Gold Certification
Elk Camp Restaurant, owned by the Aspen Ski Company and recipient of LEED Gold Certification

The Aspen Ski Company uses deconstruction methods to tear down its existing buildings and rebuild new ones. Most materials that cannot be reused in new buildings are ground into mulch. The company reused or recycled 84% of two of their buildings that they dismantled using the deconstruction process.[19]

Consigli Construction Company

Located in Milford, MA, the Consigli Construction Company has instituted a construction waste management system for its company that follows the diversion method. The company worked in conjunction with the Massachusetts Department of Environmental Protection (MassDEP) in 2001-2002 to institute a construction waste management system that would require material sorting at all of their job sites and recycling of all possible materials. They have realized an average rate of 79% waste diversion through the management system, and have seen much higher results on individual projects.[20]



Research


Research is being done on the construction industry in Hong Kong to develop a method of zero waste construction because of the rapidly diminishing landfill space.
In England the construction industry was studied to determine why waste management was so difficult to implement, and how the design of a building could change how construction waste was generated. One of the major problems that they found was a lack of interest in managing waste from many of the parties involved.

See Also:


References



  1. ^ Clark County Washington Public Works. (2008) "Construction and Demolition Wastes." 2008 Clark County Solid Waste Management Plan. <http://www.clark.wa.gov/recycle/documents/11.08%20Chapter%2012.pdf> (Nov. 28, 2014).
  2. ^ National Association of Homebuilders. (2014). "Deconstruction: For Many Builders, It’s Greener Than New." National Association of Homebuilders. <
    http://www.nahb.org/generic.aspx?genericContentID=220976&fromGSA=1> (Nov. 28, 2014).
  3. ^ Jarman, D. (1996). "Developing a Cost Effective Construction and Demolition Waste Management Plan." Virginia Polytechnic Institute and University, Blacksburg, VA.
  4. ^ Environmental Protection Agency. (2012). "What is the Solid Waste Disposal Act of 1965?" Frequent Questions: Hazardous Waste. <http://waste.supportportal.com/link/portal/23002/23023/Article/23068/What-is-the-Solid-Waste-Disposal-Act-of-1965> (Nov. 30, 2014).
  5. ^ Environmental Protection Agency. (2012). "The History of the RCRA." Laws and Regulations. <http://www.epa.gov/solidwaste/laws-regs/rcrahistory.htm> (Nov. 30, 2014)
  6. ^ Environmental Protection Agency. (1995). "Construction and Demolition Waste Landfills."<http://www.epa.gov/waste/hazard/generation/sqg/const/cdrpt.pdf> (Nov. 30, 2014).
  7. ^ Environmental Protection Agency. (2004). "RCRA in Focus." Resources. <http://www.epa.gov/osw/inforesources/pubs/infocus/rif-cd.pdf> (Nov. 30, 2014).
  8. ^ Environmental Protection Agency. (2012). "The History of the RCRA." Laws and Regulations. <http://www.epa.gov/solidwaste/laws-regs/rcrahistory.htm> (Nov. 30, 2014)
  9. ^ Waste Management, Inc. (2014). "Construction & Demolition Debris Collection and Recycling." Construction Solutions.
    <http://www.wm.com/enterprise/construction/construction-solutions/c-and-d-recycling.jsp> (Nov. 30, 2014).
  10. ^

    Laquatra, J. and M. Pierce. (2002). Waste Management at the Construction Site. Cornell Cooperative Extension, Ithaca, NY.
  11. ^

    Napier, T. (2012). "Construction Waste Management." Whole Building Design Guide. <http://www.wbdg.org/resources/cwmgmt.php> (Nov. 30, 2014).
  12. ^ Jarman, D. (1996). "Developing a Cost Effective Construction and Demolition Waste Management Plan." Virginia Polytechnic Institute and University, Blacksburg, VA.
  13. ^ Home Innovation Research Labs. (2001). "Residential Construction Waste: From Disposal to Management." Best Practices. <http://www.toolbase.org/Best-Practices/Construction-Waste/residential-construction-waste> (Dec. 1, 2014).
  14. ^

    Laquatra, J. and M. Pierce. (2002). Waste Management at the Construction Site. Cornell Cooperative Extension, Ithaca, NY.
  15. ^ Laquatra, J. and M. Pierce. (2002). Waste Management at the Construction Site. Cornell Cooperative Extension, Ithaca, NY.
  16. ^ Laquatra, J. and M. Pierce. (2002). Waste Management at the Construction Site. Cornell Cooperative Extension, Ithaca, NY.
  17. ^ Laquatra, J. and M. Pierce. (2002). Waste Management at the Construction Site. Cornell Cooperative Extension, Ithaca, NY.
  18. ^

    National Association of Homebuilders. (2014). "Deconstruction: For Many Builders, It’s Greener Than New." National Association of Homebuilders. <
    http://www.nahb.org/generic.aspx?genericContentID=220976&fromGSA=1> (Nov. 28, 2014).
  19. ^

    Environmental Protection Agency. (2012). "Not Your Typical Compost Feedstock." Resource Conservation: GreenScapes. <http://www.epa.gov/epawaste/conserve/tools/greenscapes/projects/aspen.htm> (Dec. 1, 2014).
  20. ^

    Monroe, L. (2008). "Diverting Construction Waste." Buildings. <http://www.buildings.com/article-details/articleid/5758/title/diverting-construction-waste.aspx> (Dec. 1, 2014).