December 13, 2004
By: Paul Frisman, Associate Analyst
You asked about building deconstruction.
Deconstruction is a relatively recent practice in which buildings are carefully dismantled to salvage components for reuse and recycling. Its benefits include reducing the amount of construction and demolition (C&D) waste going to landfills, conserving resources through recycling, generating marketable products from salvage, providing job training to low- and unskilled workers, and creating jobs.
It is difficult to compare the costs of deconstruction and traditional demolition. Although traditional demolition methods are less labor-intensive and time-consuming, a University of Florida study states that deconstruction can be “far more profitable” than demolition if one considers environmental costs.
A 1997 study for the U.S. Environmental Protection Agency (EPA) estimated the total cost of deconstruction for a 2,000-square foot residence at between $4.50 and $5.40 per square foot, compared to a cost of $3.50 to $5 for standard demolition. According to the study, this comparison did not reflect such potential environmental benefits as conserved landfill space and energy saved by reusing building materials.
On the other hand, a study of a Hartford deconstruction project found it cost $2 per square foot to deconstruct a building, compared to $3 per square foot to demolish it (see below).
DECONSTRUCTION COSTS AND BENEFITS
EPA on Deconstruction
EPA defines “deconstruction” as the disassembly of buildings to safely and efficiently maximize the reuse and recycling of their materials. While windows, doors and light fixtures are routinely salvaged as part of standard demolition practice, deconstruction also aims to save and reuse flooring, siding, roofing, and framing where these materials have retained their value. In some cases, EPA notes, deconstruction can save materials that are otherwise not available, such as old-growth Douglas fir and redwood lumber.
EPA calls deconstruction a “grave-to-cradle” program that helps take care of the enormous stock of buildings reaching the end of their useful lives while simultaneously reducing the pressure to mine or harvest natural resources for new construction, reducing the need for landfill space, and creating new jobs.
According to EPA, construction activities consume 60% of the total raw materials used in the U.S. economy. EPA estimates that 136 million tons of building-related C&D waste is generated annually, of which 92% is from renovation and demolition work. Only 20 to 30% of C&D waste is being recycled.
A 1997 deconstruction study prepared for EPA that closely examined the deconstruction of a 2,000-square foot home in Maryland found the total cost of deconstruction (including maximum salvage and recycling) ranged from $4.50 to $5.40 per square foot, compared to a cost of $3.50 to $5 for standard demolition (no salvage and limited recycling). But EPA noted this standards cost comparison did not reflect deconstruction's potential environmental benefits, such as conserved landfill space, the energy saved by replacing new building materials with reused materials, and lower air-borne lead, asbestos and nuisance dust at the site. The complete EPA study can be found at http://www.smartgrowth.org/pdf/deconstruction.pdf.
University of Florida Deconstruction Study
A 2000 review of deconstruction case studies by the University of Florida's Powell Center for Construction & Environment found the total diversion rate for deconstructed buildings through recycling and reuse ranged from 50% to 90%. This represents a reduction in the national waste stream of an estimated 62 to 113 million tons a year.
The Powell Center, a research organization that encourages the use of efficient and environmentally-friendly principles in architecture and planning, analyzed the feasibility of replacing demolition with deconstruction in Florida in its report. The following information is based on the report, available on line at http//www.cce.ufl.edu/past/deconstruction/final_report.html
Deconstruction Costs. According to the report, contractors view deconstruction as a waste of labor in today's economy. Traditional demolition is quick and inexpensive compared to deconstruction because buildings can be demolished mechanically, rather than by hand, and there is no need to sort salvageable from unsalvageable material. Demolition can be accomplished in a matter of hours, rather than the several days to several weeks it takes to deconstruct a building. As a result, demolition contractors have lower labor costs than deconstruction contractors. “Until deconstruction is a cost- and time-effective alternative to demolition, [its] widespread implementation is uncertain,” the report's authors said.
But the authors said this traditional view disregards the “true costs” associated with deconstruction, and state that deconstruction can be far more profitable than traditional demolition if one considers environmental costs, such as the costs of extracting the raw materials, fabricating them into finished products and transporting them to the job site.
The Powell Center report found that costs also depend on the type of building selected for deconstruction, and the local economy. When the right buildings are selected, the cost of deconstruction is less than or similar to the cost of demolition because additional labor costs are offset by the sale of salvaged materials and avoided disposal fees, the authors write.
The Powell Center report studied the deconstruction and demolition of three homes in Gainesville, Florida. Its authors concluded that the mechanical demolition of one of the three houses took far less time, but resulted in a financial loss compared to the two houses that incorporated some form of deconstruction. Among other things, the case studies found that contractors working on the deconstructed homes employed workers for a longer period of time than those working on the demolished home, but still turned a profit, and that the amount of waste sent to landfills from the demolished home was 4.3 times the amount from the completely deconstructed home.
According to the report, deconstruction also provides environmental, economic, and social benefits.
Environmental Benefits. Deconstruction provides the following environmental benefits:
1. Reducing the C&D waste stream, saving landfill space.
2. Saving natural resources that would otherwise be used, reducing the need for, and environmental impacts of, mining and timber-cutting.
3. Saving energy by reusing and recycling materials.
4. Reducing job site pollution from dust, airborne lead and asbestos.
Economic Benefits. The report found that there is a market for salvaged materials. For example, hand-hewn beams salvaged from military warehouses sold for $15 per linear foot, while old oak flooring sold for $6 per square foot, compared to $3.50 for new oak. As another example, the report cited a Berkeley, California company that began by selling imported hardwood, but has added salvaged timber to its product line. At the time the report was written, salvaged timber accounted for 15% of the company's anticipated $4 million revenue.
Social Benefits. Deconstruction provides the following social benefits:
1. Creates jobs because it requires more labor.
2. Deconstruction's basic skills are easily learned, enabling unskilled and low-skilled workers to receive on-the-job training.
3. Provides the impetus for community-oriented enterprises such as deconstruction service companies.
SINGLE HOUSE ANALYSIS
The Deconstruction Institute website, funded by the Florida Department of Environmental Protection to encourage deconstruction, depicts the land use, economics and energy benefits of deconstruction to a single house. The following information comes from its website.
The deconstruction of a typical 2,000 square-foot wood frame home can yield 6,000 board feet of reusable lumber. This is the equivalent of 33 mature trees, or the yearly output of 10 acres of planted pine.
The same home if demolished would produce about 127 tons of debris. Assuming an average disposal cost of $25 a ton, disposal would be $3,175. With an 80% diversion of waste, deconstruction would save $2,540 per home.
For every 3 square feet of deconstruction, enough lumber can be salvaged to build 1 square foot of new construction. At that rate, if deconstruction replaced residential demolition, the US could generate enough recovered wood to build 120,000 new affordable homes a year.
Because it is more labor intensive, deconstruction has the potential to create well-paid entry-level jobs in the construction trades. Labor costs for an average residential deconstruction project are about $3.64 a square foot. Equipment and operating costs for comparable demolition are $1.74 per square foot, with the difference of $1.90 per square foot being paid to the deconstruction workers. At that rate, deconstruction of 2,000 square-foot home would create 38 more worker-days at a living wage than would demolition.
To assess deconstruction's energy benefits, the Institute considers the total expenditure of energy involved in the creation of a building and its constituent materials, including extraction of raw materials, their manufacture into building materials and transport to the building site, and the equipment and tools used to assemble the materials. Deconstruction's benefits arise from the ability to both reuse or recycle many of the materials in new construction and avoid the costs of extracting additional materials for new construction.
CASE STUDY: HARTFORD PROGRAM
Since 1993, the federal Department of Housing and Urban Development (HUD) HOPE VI program has given about $500 million annually to local housing authorities to demolish, build, and rehabilitate public housing. In 1998, the Hartford Housing Authority became the first housing authority in the nation to incorporate deconstruction in its demolition program.
The housing authority worked with the Institute for Local Self-Reliance (ILSR), a nonprofit research and education organization, and Manafort Brothers construction company to deconstruct six units of the Stowe Village Public Housing complex. The housing authority provided $50,000 above traditional demolition costs to support a training program. On its web site, Deconstruction at Work: Hartford, Connecticut, ILSR reports the following findings in the areas of job training, sale of recovered materials, costs savings, and environmental impact.
Job Training and Creation
The project recruited nine worker-trainees from Hartford public housing apartments, some of whom had been raised in the project they were demolishing. According to ILSR, training was completed in six weeks, and cost $6,000 per worker, much less than the estimated $15,000 per person HUD training allowance.
Sales of Recovered Materials
According to ILSR, the project recovered and found markets for all recovered materials, generating $9,000 in sales. At Stowe Village, 10% of the materials removed were recycled and another 40% was made available for reuse. Based on these figures, ILSR estimated deconstruction could recover as much as 32 million tons of waste annually.
ILSR reported that trained workers could deconstruct a building at a cost of $2 per square foot, compared to $3 per square foot for demolition. We were unable to learn in time for this report how ILSR arrived at these figures. However, according to ILSR, Manafort Brothers reported that deconstruction saved money in waste disposal and helped build a workforce of trained employees able to work on both construction and deconstruction projects. The deconstruction project also helped Manafort create a steady stream of usable low- or no-cost construction material for its construction projects, ILSR said.