Diversion of construction waste is an important element of green building practice, as it helps to conserve energy and resources, increase efficiency, and reduce building cost.  By volume, construction waste is primarily composed of cardboard (38%), wood (24%), drywall (11%), metals (4%) and masonry (1%).  Much of the wood waste is considered 'clean' because it is unpainted and untreated (1). 

Construction waste is diverted from landfills in the same way other types of waste are diverted - reduction, reuse, recycling.  Together, these three strategies help to reduce demand for new raw materials, reduce the amount of waste sent to a landfill, and reduce the total cost of the building venture.  Excess waste is often generated during the construction process as a result of changes in building plans, material damage during construction, and ordering of more material than needed.  It follows that programs that improve working methods and increase staff awareness can be highly effective in reducing construction waste.  Many materials removed from a construction are suitable for reuse.  These include topsoil, roof tiles, bricks, and timber.  Excess cardboard, non-reusable wood, plastics and metals can be recycled (2).

In addition to the 3R strategy, other methods of reducing and managing construction waste can also be effective.  For example, educational and promotional programs can help to educate companies on alternative waste management.  Further, innovations in design and technology can address waste issues in a variety of ways, such as reducing excessive packaging, or increasing the lifespan of products.  Lastly the implementation of waste management policies and regulations help to ensure that companies are responsible for the waste generated by their activities.

In 1994, the Ontario Ministry of the Environment passed new regulations (O.Reg. 102/94) for construction and demolition sites larger than 2000 square metres.  The regulations require these projects to complete a full work plan and thorough waste audit prior to their commencement.  This is intended to help predict the amount and type of waste the project will generate, and thereby provide an opportunity to develop a strategies to reduce, reuse, and recycle as much waste as possible (3).

Sources:
¹ Oikos, 2008. Construction Waste: Types and Quantities (webpage).
² Scottish Environmental Protection Agency, 2009. The Small Environmental Guide for Construction Workers.
³ Ontario Ministry of Environment, 2008.  A Guide to Waste Audits and Waste Reduction Work Plans for Construction and Demolition Projects.