A new and innovative component of the green building movement is building deconstruction, an alternative to demolition for the removal of unwanted structures.
Deconstruction is new by name, but not by practice, as the recovery and reuse of materials in order to build new structures is as old as buildings themselves. Reuse of materials might be considered one of the “original” green building techniques, along with the use of local materials.
In the pre-industrial era, materials conservation was driven by the high intensity of the labor effort required to harvest and prepare them. Reuse
of materials provided an economic advantage. In the mid-to-late 20th century, the emergence of machine-made and mass-produced materials,
chemically complicated materials, and the relatively low cost of oil allowed this basic idea of “waste not, want not” to fall from usage in
the creation of built environment. This trend has begun to reverse as:
The price of key materials such as concrete and steel increases.
Tipping fees at landfills increase.
The siting of new landfills becomes more problematic.
The price of transportation increases.
Some building materials have become more scarce or degraded in quality.
The overall green building movement has included materials conservation and waste reduction among its key principles.
A recent EPA study indicated that roughly 136 million tons of waste are generated annually from construction, renovation, and demolition (CRD). Depending on local conditions, CRD can comprise anywhere from 25% to 40% of the total waste in a community. Of this amount, the EPA has estimated approximately 92% is produced by building renovation and demolition, with 8% coming from new construction projects.
Deconstruction continues to gain stature in the building industry because of all these issues. Furthermore, legislation is being enacted to require it—such as in California and Massachusetts—the former mandating the 50% diversion state-wide of all waste, and the latter banning certain construction and demolition debris materials from disposal, including concrete, clean wood, asphalt, and metals. As the construction industry and markets become more mature at handling this stream of diversion, more states and municipalities will likely increase restrictions on the disposal of CRD debris materials.
Another factor supporting deconstruction is the increasing number of used building materials stores. As of this book’s printing, there are approximately 1,000 of them, both for-profit and non-profit (aside from architectural antique stores) in the U.S. Roughly 200 of these are Habitat for Humanity (HfH) ReStores. To illustrate the level of growth in the reused building materials industry, the oldest HfH ReStore was established in 1987, and almost 60% of all their stores have been established within the last five years. The average ReStore is over 10,000 square feet, and in aggregate they produce about $40 million in net revenues per year for their affiliates.
Deconstruction versus Demolition
Building deconstruction is the disassembly of building components to recover the maximum amount of reusable and recyclable materials in a safe, environmentally responsible, cost-effective manner. Generally, buildings are deconstructed in the reverse order of how they were constructed—last on, first off (LOFO). All salvageable items are removed and reused on the site for a new project, sold, or donated. Non-salvageable items are recycled to the extent possible, and the remaining debris is taken to the landfill. Deconstruction can be applied to total building removal, and also to remodeling.
Standard demolition practices may include elements of deconstruction, such as “cherry-picking” or “skimming,”—or removing high-value items before demolition. Demolition practice may also include recycling otherwise unusable items, like concrete for use as aggregate for new foundations or walkways.
The principal distinction between deconstruction and demolition is deconstruction’s goal of diverting as much material as possible from landfills. Deconstruction may involve both reuse and recycling, depending on the technical requirements of a safe process and the highest and best use of the constituent components and building materials. Demolition tends to have a much lower threshold for recovering reusable materials and is typically focused on speed and the mechanical reduction of the mass of a building in order to make the disposal of materials as efficient as possible. As a result, standard
demolition practices are more compatible with recycling than reuse.
Reusing Salvaged Materials on the Same Site
In some cases, the materials that are removed from the old building can be cleaned, refurbished, and/or reconfigured as components for either a
new building or for added/remodeled space on the same site.
Incorporating these salvaged materials into the new project is a “greener” approach than selling or donating them elsewhere because of the reduced energy needed to transport the old materials and to manufacture the new (replacement) ones. Other benefits include avoidance of costs related to marketing and selling the salvaged materials, additional LEED points, and possible funding from grants.
The old materials would, of course, have to fit in with the new building design and specific applications, in consideration of limitations such as ungraded lumber and lack of warranties. Extra time might also need to be scheduled to clean and modify materials at the site before they are reinstalled.
Economic Benefits
Aside from the LEED points and environmental benefits (saving natural resources and energy, minimizing site disturbance and dust, and
reducing landfill waste), deconstruction has clear economic benefits and Reuse of salvaged materials in a new structure on the site reduces
both materials and transportation cost (and provides LEED points.)
The donation of building materials to nonprofit organizations like HfH ReStores provides tax benefits for building owners and makes lowercost
materials available for affordable housing and do-it-yourselfers.
Owners who work with nonprofit organizations to conduct salvage and deconstruction offset the higher labor costs these efforts require (versus
demolition) with the sale of (or tax credit for) salvaged materials. (The deconstruction needn’t be performed by the nonprofit as long as the materials it generates are donated to non-profits.)
This article is an excerpt from the book Green Building: Project Planning & Estimating which can be purchased through the RSMeans Bookstore.
This new 2nd edition has been completely updated with the latest in green building technologies, design concepts, standards, and costs. Includes Means’ Green Building CostWorks CD at no additional cost.
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