Waste Management Update #4: Deconstruction

by NAHB Research Center

Each year, as many as 100,000 residential buildings are demolished in the United States. This represents more than 8 million tons of wood, plaster and drywall, metals, masonry, and other building materials, most of which will end up in local landfills.

Deconstruction is a new term to describe an old process--the selective dismantling or removal of materials from buildings before, or instead of, demolition. Typically, when a building reaches the end of its useful life, heavy equipment is brought in to demolish the structure. All parts of the structure are rendered into rubble--a varied mix of wood, masonry, metals, and other materials. In some cases, particularly with large concrete and steel buildings, raw materials may be processed and recycled. For most light-frame residential buildings, the demolition waste ends up in either a municipal or construction and demolition landfill.

It is possible to salvage building components, keeping the higher value of materials for reuse. Wood flooring, raised panel doors, ornate interior and exterior trim, electrical and plumbing fixtures, even framing and bricks can have salvage value of up to 75% of the item's original value. Add to this value the avoided disposal costs and a question arises: Can relatively low-skilled deconstruction labor dismantle a building more cost-effectively than heavy equipment can demolish it?

DECONSTRUCTION CASE STUDIES

The Whole House Recycling Project. In 1993 in Portland, Oregon an architect and a local demolition firm combined forces to document the economics of dismantling a 1,280 square foot, two-story house. They found that the hand labor required to dismantle the building for salvage was competitive with the cost of conventional demolition. In addition, the following salvage values and reduced disposal costs resulted in net income of $4,500. While high tipping fees and well-established end use markets in Portland may make this a special example, the results suggest that deconstruction can be a viable alternative to conventional demolition.

Salvaged Item Framing Lumber T&G Siding Doors Brick

% value of retail 40 50 30 55

Ft. McCoy Barracks. The Directorate of Public Works (DPW) for the Army's Ft. McCoy in Wisconsin developed a way to deconstruct many of the buildings that they slated for demolition at a fraction of the cost of conventional demolition. A service-type contract was written to permit local individuals to submit sealed, no-minimum bids for building material salvage. The DPW removed hazardous materials from the buildings prior to contract winners coming on site to salvage framing, sheathing, and flooring. The Army provided dumpsters for disposal, a site safety program, basic asbestos and lead paint training, and final site clearance and grading.

Recovery rates are averaging 85%, the Army DPW is incurring costs of $2 per square foot (compared to the $20 per square foot that some Army installations are facing), and the deconstruction crews have built houses, hunting cabins, garages, sheds, and even two churches out of the salvaged building materials.

ISSUES

Despite these and many other success stories, there are key issues to be addressed as deconstruction is explored

• Rules of thumb. Are there general principles to be used in determining how and when to employ deconstruction?
• Time. How much more time will deconstruction generally take than demolition?
• Lead and asbestos. Do these materials need to be handled any differently for deconstruction than they would be for conventional demolition?
• Worker compensation and general liability. How will insurance companies evaluate deconstruction activities?
• Grading stamps. Will local building inspectors accept salvaged framing materials in equal substitution for new framing--if framing lacks a stamp, how easily can the framing be regraded?
• Markets. How are salvaged building material markets located or created?

Many of these issues are being investigated as part of a pilot deconstruction project being conducted by the Research Center in Baltimore, Maryland. The results of this project will be available in the fall of 1997.

Copyright © 1996 NAHB Research Center, Inc. This work is used with the permission of the copyright owner for publication on the Smart Growth Network web site. Any copies of this work shall include this copyright notice.