March 30, 2010 - Phil Waier, PE, LEED AP
A component of the “Green” movement is building deconstruction. Rather than demolishing a structure and delivering the debris to landfill, building deconstruction provides for the careful removal and reuse or recycling of building materials. The materials can be stored and reused on the existing site thus eliminating transportation charges. The alternative is to sell or donate the deconstructed materials.
Typical materials considered for deconstruction include the following:
- Interior doors and frames
- Structural framing
- Brick masonry
- Plumbing fixtures
- Wood strip flooring
- Roof sheathing boards and metal roofing
The decision to deconstruct is based upon several factors; the first is a site assessment. This involves evaluating the materials based upon type, quality level and condition, quality and installation method. Another aspect of site assessment is the adequacy of the site to store and clean/process the materials. The second consideration is the potential market for the materials if they are not being reused for the project. The current price for new materials must be compared to the potentials sale price of the deconstructed material. That price is based upon the condition and quality of the deconstructed material. The presence of local salvage retailers and the ability to market and cost of transporting the materials is also a consideration. Safety is a key concern in the planning and executing of a deconstruction project.
Aside from the LEED incentives/credits for deconstruction there are a number of other reasons to deconstruct.
- Newer replacement materials may be scarce or of lesser quality. An example is the structural timbers used in many old mill buildings. These timbers are frequently larger and longer that those commercially available today. Also their old growth strength is greater than wood from newer forests.
- Demolition disposal costs continue to escalate as solid waste land fills are closed and new land fills are plagued by permitting issues.
- Commodities such as steel, copper and aluminum are becoming more expensive and substantial energy can be saved by recycling.
A final consideration in building deconstruction is schedule. The deconstruction process is more labor intensive than demolition, therefore time must be provided in the construction schedule to allow for the process.
In the final analysis the cost, time, and environmental considerations will be the determining factors.