Disassemble-a-Building

The past ten years have seen an explosion in sustainable design among architects in the United States. As a result, particular attention is being paid to the materials and systems that go into buildings. Many materials are now recyclable, are made of recycled content, or contain raw materials that are grown and harvested in a replenishable manner. Even construction and demolition waste is being conserved and recycled in many cases.

Many new buildings are built over the remnants of a previous structure, or utilize the shell of an existing building. What happens if the architect looks down the road to the (inevitable) eventual demise of his or her own design work? What portion of the building that was carefully designed and specified to use environmentally responsible materials is itself readily recycled or returned to be raw materials for the current generation of products?

Consider a typical product used in buildings. Is it a simple material, i.e. does it contain raw materials or components that are readily separated or recycled (not just downcycled)? Or is it a bonded, fused, composite, laminated, hybrid assembly that cannot readily be deconstructed into its constituent parts? Unfortunately this is the case more often than not, even if for the best reasons of functionality, durability, or maintenance.

So the recycled wood laminate flooring is itself not recyclable, the vinyl composite tile on the floor isn’t recyclable and likely won’t even be removed from the concrete slab before the entire floor is demolished. The plastic laminate cannot be removed from the urea-formaldehyde-free particleboard underlayment. But even if it could, the matrix of wood and adhesive can’t be separated out of the underlayment. Even ubiquitous light bulbs, whether incandescent or CFL, still aren’t recycled.

Even as architects make important strides toward being good stewards to the environment, there are limitations to the benefit. And sometimes the benefit is only really shifting the impact and problem further down the road to the future when it is hoped there will be a way to deal with it, if it is even considered at all.

The components that are recyclable are seldom readily segregated into the appropriate elements that facilitate the recycling process, even if it can be done. Materials that can be recycled are commonly combined in ways that prohibit their eventual separation and eliminate the possibility of being recycled, or make the work required to do so significant enough that it becomes a disencentive. Asphalt membranes are bonded to masonry, rubber is bonded to copper, plastic is bonded to metal, insulation is bonded to sheathing, in ways that are a challenge to safely or cost-effectively separate. When the time comes to deconstruct the building, these components cannot be recycled, and must therefore be disposed of as waste. In contrast, if these components were designed in such a way that they could be separated when the time comes to deconstruct the building, the sustainable measure of the building will be increased considerably.

The consequence of the current materials and systems used in buildings is that construction methods are not conducive to eventual recycling or reuse of the components that go into buildings. Buildings are assembled as a one-way process, with little or no accommodation for future dis-assembly for effective re-recycling and reuse yet again further down the road. Is there a way for architects to look further down the road and consider the day when their own work can become the raw materials for another building project?

Consideration for building components that can be disassembled and construction methods that allow the future deconstruction of buildings instead of their wholesale demolition will enable the elements of a building to be re-used or recycled more effectively. Think of an old wooden barn – while a permanent, durable and practical building, the simple construction methods of pegging, notching, bolting, and nailing the structure and cladding together created a building that was sturdy, but could be taken apart completely and rebuilt in another location exactly as it was before.

Using materials that are simpler in composition and readily recyclable round out the picture of designing a building for its inevitable replacement. New architecture that strives for this understanding of building assembly while meeting the demands of the modern construction industry would provide an opportunity to improve on the long-term recyclable profile of the structure, and provide new design opportunities as well.

AGB 3/2005