Construction Waste Management

by Tom Napier, Research Architect
U.S. Army Corps of Engineers, Engineer Research and Development Center / Construction Engineering Research Laboratory

Introduction

C&D landfill cell

Responsibly managing waste on a construction jobsite is a vital component of sustainable building. In this context, managing waste means minimizing the construction waste or demolition debris (C&D) that leaves the jobsite for landfill disposal.

In 1998, the U.S. EPA estimated that 136 million tons of building-related waste is generated in the U.S. annually, which is 25% to 40% of the national solid waste stream. A 2003 update shows an increase to 164,000 million tons annually, of which 9% is construction waste, 38% is renovation waste, and 53% is demolition debris.

C&D waste disposal triggers a sequence of adverse effects that are not always apparent to building professionals. These include the loss of useful property, wasted materials and embodied energy, greenhouse gas generation, and environmental stressors associated with producing new materials instead of using existing materials. The number of C&D landfills is declining, which means fewer disposal options, greater hauling distances, and increased fuel consumption and vehicle emissions. Capping, closing, and monitoring landfills, and cleaning up leaking or contaminated landfill sites drain public funds.

EPA also estimates that only 20% of C&D waste is being recycled. This suggests an enormous potential for improvement. It also suggests a significant resource is available for future use. In the book Cradle to Cradle, William McDonough draws the analogy to natural systems where waste is food. "Technical waste" should become "industrial food."

Left: Commingled C&D waste in roll-off and Right: Methane vent at landfill

Description

A. Definitions

Construction Waste: Waste materials generated by construction activities, such as scrap, damaged or spoiled materials, temporary and expendable construction materials, and aids that are not included in the finished project, packaging materials, and waste generated by the workforce.

Demolition Debris: Waste resulting from removing a building from the site by wrecking.

Land Clearing Debris: Vegetative waste materials removed from a site.

Disposal (or Landfilling, or Landfill Disposal): Depositing materials in a solid waste disposal facility licensed for the subject materials (in this case, C&D materials).

Recycling: Introducing a material into some process for remanufacture into a new product, which may be the same or similar product or a completely different type of product.

Salvage: Recovery of components, products, or materials for the purpose of reusing them for the same or similar purposes as their original use.

Reuse: The subsequent use of a material, product, or component upon salvage.

Deconstruction: The systematic disassembly of a building, generally in the reverse order of construction, in an economical and safe fashion, for the purposes of preserving materials for their reuse.

Source Separation (or Segregation): Keeping materials separated by type from the time they become scrap or waste until the time they are salvaged or recycled.

Off-Site Separation: Sorting and separating commingled waste at a location other than the construction jobsite, that location having been established for the purpose of recycling.

Commingled: Materials of varied types deposited into the same receptacle or pile, or mixed together during demolition.

B. C&D Waste Materials

The vast majority of construction waste and demolition debris materials can be reused on site, salvaged for reuse on-site or elsewhere, or recycled. Diverting 90% of construction jobsite waste and over 80% of demolition debris from landfill disposal is not uncommon. These materials include:

• Landscape and land clearing debris (green wood materials)
• Asphalt pavement
• Gravel and aggregate products
• Concrete
• Masonry scrap and rubble (brick, concrete masonry, stone)
• Metals (ferrous and nonferrous)
• Clean wood (dimensional lumber, sheet goods, millwork, scrap, pallets)
• Plastics (films, containers, PVC products, polyethylene products)
• Asphalt / bituminous roofing
• Insulation materials
• Glass (un-tempered)
• Door and window assemblies
• Carpet and carpet pad
• Fibrous acoustic materials
• Ceiling tiles
• Plumbing fixtures and equipment
• Mechanical equipment
• Lighting fixtures and electrical components
• Cardboard packing and packaging
• Others

Note that disposal of hazardous materials is governed by the prevailing regulations at the project's location, and is not addressed in this Resource Page.

C. Best Management Practices

How waste management, or diversion, is accomplished, and to what extent, depends on specific project requirements and conditions. Several issues contribute to an overall waste diversion strategy.

1. Waste Management Planning

Waste management should be an integral part of a project's development. Each of the principal project participants—the Owner, their Architectural and Engineering (A/E) services (or Construction Management consultant), the Contractor, and Subcontractors—will engage in waste management to some degree throughout the project. Initially, the Owner and their A/E must establish waste reduction goals and define what levels of diversion are achievable and reasonable under the project's conditions.

2. Facility Design

The Contractor is responsible for the means, methods, techniques, sequences, and procedures of construction, which include waste disposal methods. However, the A/E's design team can contribute to waste reduction in several ways. These include:

1. Observe Value Engineering principals. Perform multiple functions with one material rather than requiring multiple materials to perform one function. Design to optimize systems' and components' use. Avoid extraneous materials that do not contribute to function.
2. Be efficient in area and volume. If less material is required by the design, less waste is generated at the jobsite.
3. Observe standard material and product dimensions. Locate features "on module" to the extent possible to reduce cutting and special fitting, which creates scrap.
4. Where possible, select construction systems that do not require temporary support, shoring, construction aids, or other materials that will be disposed of as debris during the project.
5. Where possible, select materials that do not rely on adhesives, which require containers and create residue and packaging waste. Furthermore, adhesives inhibit salvage and recycling at the end of the component's or building's life.
6. Where possible, reduce requirements for applied finishes, laminates, coatings, adhesives, and the associated scrap, packaging, and waste. Select materials with integral finishes.
7. Where possible, avoid materials which are sensitive to damage, contamination, environmental exposure, or spoilage on-site, which increase the potential for jobsite waste.

3. Construction Contract Requirements

The Owner and their A/E (or CM consultant) must determine how their waste management requirements will be represented in the contract documents and incorporated into the project. Several provisions are relevant to the project's overall waste reduction performance.

1. There are essentially three ways to represent waste reduction requirements in the contract documents.
   • Describe the waste reduction goals and rely on the Contractor's own initiative to achieve them. This may be effective if the Owner and Contractor share a good working relationship, and encouraging the Contractor is sufficient for them to "do the right thing."
   • Specify definitive minimum waste and debris diversion criteria. This is commonly incorporated into the Demolition specification as a numerical criterion, such as "divert from landfill disposal a minimum of 75% of the non-hazardous construction waste generated at the jobsite."
   • Develop incentives to reward the Contractor. This may be implemented as an award-type incentive based on the diversion rate, or by including Options in the Bid Schedule for each of several ranges of diversion rates.
     Note that simply requiring a specific LEED rating does not guarantee credit MR 2.1 or 2.2 (50%, and an additional 25% C&D waste diversion, respectively) will be attained. If the Owner, and their A/E or CM consultant desire to rely only on LEED as their requirement for environmental performance, they can still specify that MR-2.1 or MR-2.2 are mandatory for the project.
2. Require the Contractor to submit a C&D Waste Management Plan. Typically, the Plan includes the following:
   • Name of individual(s) responsible for waste prevention and management.
   • Actions that will be taken to reduce solid waste generation.
   • Description of the regular meetings to address waste management.
   • Description of the specific approaches to be used in recycling/reuse.
   • Waste characterization; estimated material types and quantities.
   • Name of landfill and the estimated costs, assuming no salvage or recycling.
   • Identification of local and regional reuse programs.
   • List of specific waste materials to be salvaged and recycled.
   • Estimated percentage of waste diverted by this Plan.
   • Recycling facilities to be used.
   • Identification of materials that cannot be recycled or reused.
   • Description of the means by which any materials to be recycled or salvaged will be protected from contamination.
   • Description of the means of collection and transportation of the recycled and salvaged materials.
   • Anticipated net cost or savings.
     Some examples of C&D Waste Management Requirements and Plans are provided in Additional Resources, below.
3. Require the Contractor to document their actual waste diversion performance throughout the project. The Waste Management Plan, therefore, should also include progress reporting procedures to record actual diversion and cost corresponding to each diversion and cost estimate.
4. As the accepted Plan is a part of the contract document, it should be incorporated into the Contractor's Quality Control and Owner's Quality Assurance processes. Some public Owners go so far as to specify that progress payments will not be approved until updated actual diversion performance reports are submitted.
5. Vest title to debris and waste materials to the Contractor, and allow the Contractor to accrue the economic benefits. These include cost avoidance through reduced debris tipping expenses, revenues from salvaged and recycled materials, and cost avoidance by using materials taken from the jobsite back into the project.

4. Jobsite Waste Reduction

There are a variety of ways a Contractor can divert construction waste or demolition debris at the jobsite. The following general practices are common:

1. Up to 10-12% of a project's construction waste stream can be cardboard alone. While protecting new materials is necessary, the Contractor can direct their subcontractors and suppliers to reduce extraneous packing and packing.
   • Purchase materials in bulk where possible. Avoid individual packaging for volume purchases.
   • Use returnable containers and packing materials
   • Reuse non-returnable containers on the jobsite to the maximum extent possible. Develop one-hundred-and-one-uses for plastic barrels, buckets, and tubs.
   • Give away non-returnable containers. Contact local and community organizations (schools, youth groups, community service groups, Habitat for Humanity, others similar).
2. Use scrap in lieu of cutting full new materials. Direct subcontractors and trades to collect and keep scrap at cutting and fabricating locations. Collect paints and liquids from almost-empty containers; avoid disposing of useable materials simply because there is not enough in one container to finish a job.
3. For materials that are heated, mixed, exposed to environmental conditions, or otherwise subject to spoilage, limit preparation of these materials to quantities which can be installed within their expiration times. Working in smaller batches will reduce the necessity to throw out expired or spoiled materials. Ensure volatile materials, and materials that degrade when exposed to heat, cold, or moisture are protected from spoilage and are not wasted.
4. Recycle damaged components, products, and materials, or disassemble them into their constituent materials for recycling.
5. Establish a return or buy-back arrangement with suppliers. Alternatively, unused, or used but serviceable materials and products can be sold to architectural salvage or used materials retail outlets. Donations to a non-profit outlet, such as a Habitat for Humanity (HfH) ReStore, are usually tax-deductible.

C&D recycling pick line

6. The Contractor may contract with a C&D recycling firm who accepts commingled debris. At the recycling site, concrete and masonry rubble are separated out of the debris for crushing into aggregate products. The remaining debris is typically crushed or shredded, then conveyed along a pick line for sorting and recycling. Recycling commingled debris and waste off-site requires virtually no adjustment in practice on the Contractor's part. C&D waste recyclers generally describe their fees as "competitive" with landfill disposal, which means a modest savings over prevailing landfill tipping fees. This method typically achieves a very high diversion rate. However, clean wood is frequently sold for boiler fuel, and some agencies do not allow incineration to be counted as diversion.
7. The Contractor may contract with individual recycling firms who deal in specific materials, in addition to a general waste hauler. This requires the Contractor, subcontractors and tradespersons to segregate waste, deposit it in the appropriate receptacles, and guard against contamination by other materials. The key to effective jobsite segregation is to place receptacles in the path of least resistance to the workforce, training the workforce to observe segregation practices, and policing the jobsite to prevent contamination. The construction process lends itself to on-site segregation. As trades enter and leave the jobsite, each generates a relatively homogeneous waste stream, given the specific tasks and the materials with which they work. As the recyclable materials are segregated, the recycling firms generally offer a higher price for the material (if the contractor hauls), or a lower hauling rate (if the recycler hauls). Alternatively, the Contractor can contract with a waste hauler who provides receptacles for recyclable materials and debris, and hauls all materials as a one-stop service. While some contend site separation increases the cost of construction, efficient materials movement and site layout should minimize any increased effort.

Left: "Wood only" receptacle and Right: "Metals only" receptacle with steel deck trimmings

8. The waste diversion potential in a demolition scenario is considerable. The building's construction type and project schedule are the two primary factors in determining what and how salvage, reuse, and/or recycling can be accomplished. Consider the following:
   • Develop the project schedule to accommodate salvage, reuse, or recycling. The quality and quantity of materials salvaged is a direct function to the time available for salvage.
   • Prior to demolition, salvage as much useable material and components as the schedule will allow. Windows and doors, wood flooring, cabinetry, architectural millwork, electrical fixtures, plumbing fixtures, mechanical equipment … anything that can be detached and removed … can be usually be salvaged and reused. When developing the C&D Waste Management Plan, identify the most accessible and valuable materials, thereby optimizing the application of resources to this task.
   • Concrete and masonry materials can be recycled to produce aggregate. This may be accomplished on-site with mobile equipment, or rubble can be hauled to a permanent recycling facility. Preferences vary among demolition contractors and recyclers about whether the building should be gutted prior to demolition, leaving only concrete and reinforcing to be crushed, or demolished intact, and the debris sorted as part of the concrete crushing process. Consider how the recycled concrete aggregate (RCA) will be used, what RCA products are most useable, and how the rubble should be processed to produce these products. If aggregate materials are required for the project, on-site recycling can provide these materials at a reduced net cost. The Construction Materials Recycling Association (CMRA) can provide information on methods and service providers.
   • Landscape materials and wood that is not painted with lead-based paint, treated with an arsenic-based preservative, or otherwise contaminated with a hazardous or toxic material can be shredded into mulch, composted, or chipped for boiler fuel. This can be accomplished on-site or off-site. If mulch or compost is required for the project, shredding on-site can provide these materials at a reduced net cost.
   • Structural steel and metals are almost universally recycled. This should be standard practice with any demolition contractor.
   • Old growth timber is a valuable material and will usually justify the time required for a more delicate removal process. Timbers are generally sold through timber brokers to be cleaned and resold for timber framing, or as feedstock for high quality architectural millwork.
   • Some species of dimensional lumber can also be quite valuable. Wood framed buildings can be partially or totally deconstructed. While this is often a more labor intensive approach, cost avoidance and the value of the materials can offset initial cost. The Building Materials Reuse Association (BMRA) can provide information on deconstruction contractors and used building materials retail businesses.
   • If none of the alternative salvage, reuse, or recycling options are possible, mixed demolition debris can be hauled to a C&D debris recycling facility, as described above.

Left: Segregated piles and Right: Concrete recycling

Left: Wood building deconstruction and Right: Salvaged lumber at the jobsite

Application

Waste reduction practices are applicable to virtually any construction and demolition project scenario. The goal is to divert materials from landfill disposal to the greatest extent practical under the circumstances.

There are two opinions about whether this is a realistic expectation under real world project conditions. One is that waste reduction costs money, and the other is that waste reduction saves money. As with any construction project, planning and project management will ultimately dictate whether waste reduction is accomplished within the established cost, schedule, and quality parameters.

The greatest uncertainty is usually the availability of salvage and recycling services and outlets, and any costs associated with handling these materials. Resources are available to help Owners, A/E and CM professionals, and Contractors familiarize themselves with the salvage, reuse, and recycling industries and infrastructure. Examples are provided in Additional Resources, below.

The following sources provide case studies, or collections of case studies, on C&D waste diversion.

• Air Force Center for Environmental Excellence, C&D Guide (See Appendix D for 19 case studies)
• BuildingGreen.com, 14 articles and 70 case studies on C&D waste management
• BuildingGreen.com, 19 articles on C&D waste management
• California Integrated Waste Management Board
• EPA Office of Solid Waste and Emergency Response
• Homestead FL Habitat for Humanity, Construction Waste Management Handbook
• National Demolition Association Position Paper, 6 case studies
• Triangle J Council of Governments, NC, "WasteSpec" includes several case study applications of the WasteSpec document. (select "case studies")
• University of Florida Center for Construction and Environment
• Vermont Waste Management Division
• WasteCap Wisconsin

Emerging Issues

Few regions are experiencing a shortage of C&D landfill space. However, the increase in tipping fees (especially in the Northeast and the Northwest); regulations excluding C&D materials from landfills; the decline of the numbers of C&D landfills in the U.S. (26% fewer between 1990 and 2002); and more rigorous standards for new landfill design, all suggest landfill disposal of C&D waste will be significantly more expensive in the future.

The architectural, engineering, construction, and waste management industries are becoming more sensitive to C&D waste reduction. Public awareness of waste reduction and recycling has elevated to a point where public policy is also directing C&D waste diversion. Public agencies are encouraging through policy, or requiring by ordinance or regulation, waste diversion in both public and private construction. Many agencies have developed resources such as best practice guides and market directories to facilitate waste diversion at the project level. Furthermore, the U.S. Green Building Council's LEED rating system's MR-2.1 and MR-2.2 credits provide incentive to reduce waste in "green building" design and construction.

The growth in numbers of architectural salvage and used building materials retail businesses, and C&D recyclers is further evidence that building material salvage and recycling is becoming an important segment of the construction industry.