In 1992, as part of the research for this guidebook, project staff and co-sponsors worked together to estimate the types and amounts of wastes generated at local construction and remodeling projects. (The complete Construction Materials Recycling Project Composition of Construction Waste Report is available from the Metropolitan Council Solid Waste Grants Department or Innovative Waste Management.) Because the report was not a scientific study, but a compilation of estimates by industry professionals, the amounts are reported as a range of percentages.
For our purposes, "waste" includes all materials hauled away from a job site to be landfilled, burned, recycled, or salvaged for reuse. New, leftover materials that are returned are not considered wastes. To estimate percentages, we considered the total volume of wastes generated over the course of a typical project. For example, in Table 1: Residential New Construction, wood waste is listed as "20-35 %." This means that wood makes up 20 to 35 percent of the entire volume of waste generated by a typical new residential construction project.
Waste types and approximate percentages are given separately for residential and commercial new construction.
Residential New Construction (See Table 1). The predominant waste types , from residential new construction are wood, 20-35 percent; drywall, 10-20 percent; and cardboard, 5-15 percent. According to Materials Recovery Ltd., a construction waste recycling firm, approximately 24 percent of the constrution waste entering its facility is dimensional lumber suitable for processing. Shingles, concrete, and fiberboard each make up another 1-8 percent of the waste from typical new home construction. The remaining waste types each typically comprise one percent or less of a project's waste stream.
Commercial New Construction (See Table 2). The predominant waste types from commercial new construction are wood, 20-30 percent; concrete and
Dimensional Lumber, Manufactured Wood Products, and Treated Wood
These percentages do not distinguish between dimensional lumber, manufactured wood products (such as plywood and particle board), and treated wood. However, because recycling markets are more common for dimensional lumber than for manufactured wood products, we investigated further.
A survey of four lumber yards revealed that, typically, 60-70 percent of the wood purchased for a construction project is dimensional lumber and 30-40 percent is manufactured (usually glued) wood products. Wood treated to resist rot and moisture amounts to less than 5 percent of the total wood used on a project. (See the Reference Section of this.guidebook to find out where to seek information about disposing of treated wood.) The lumber yard respondents said that the use of manufactured wood products is increasing, and noted that some products could be considered recycled products themselves.
block, 10-20 percent; drywall, 5-10 percent; and cardboard, 5-10 percent Secondary materials in the commercial construction waste stream are steel, 1-8 percent, and brick, 1-5 percent. Also in the 3 percent range are extruded polystyrene (rigid) insulation, kraft paper packaging, and plastic sheeting and bags. Electrical wire makes up about 2 percent of a project's waste, and over-spray from fireproofing products makes up 0-5 percent of the waste.
Remodeling. Wastes from remodeling projects vary so widely that estimating their percentages was beyond the scope of this report Instead, we note that all materials and equipment that become part of a building during the building process may eventually be replaced. These materials then enter the waste stream. Wastes generated during the construction phase of remodeling projects are similar in composition to those from new construction.
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