Thus far I’ve been focusing on the deconstruction and reuse of structural members— the part of a building that literally keeps the building standing. My point has been that instead of building with the expectation of demolishing this “skeleton” and treating it as waste, we can build in a way that facilitates disassembly and reuse of those structural members. This way, we both reduce our dependence on virgin materials AND cut back on the emissions associated with the materials and the construction process. However, I’ve skipped over two important aspects of “Design for Deconstruction” (DfD) in saying this.
Are the structural members the only things worth salvaging in the end?
If there’s enough worth saving, is the demolition really warranted?
To answer both questions, it is useful to envision buildings as entities made of different layers with different lifespans [1].
In the ideal DfD building, each of these layers would be separable. That way, whenever the mechanical system needs upgrading or an interior wall needs to be relocated, it would be possible to change just that component while interfering minimally with other components of the building. This is commonly referred to as building for “flexibility” or “adaptability,” and has the effect of making renovations less costly— in terms of materials, energy, and financial cost. Imagine being able to apply these savings to the $360 billion worth of renovations happening in the US annually [2].
It’s also worth noting that beyond trashing potentially useful materials during renovations, tons of waste are coming out of demolition projects in the US every year. And some studies are showing that many of these demolitions take place not because the building at hand is structurally unsound, but because someone wants a different type of building where the current one is standing [3]. In other words, if DfD and deconstruction were commonplace, we could be salvaging a very large quantity of perfectly reusable materials.
So as a roundabout answer to the two questions I posed, I’d say that in an ideal world, we’d shift from assuming that all building materials will end up in a landfill (with maybe some exceptions) to assuming that all building materials will be kept and reused (with maybe some exceptions).
But what would this “ideal world building” look like if you were to visit?
Actually, it is possible to visit. They may not be “100% DfD” quite yet, but there are already a number of projects in the US that have taken this message to heart.
CHARTWELL SCHOOL, CALIFORNIA [4]
The Chartwell School is a K – 8 school in Seaside, CA, for children with language-learning difficulties.
Here are some characteristics of the building that make the structure both easier to renovate and relatively easy to disassemble and reuse at the end-of-life stage.
Many interior walls in the school were designed to be non-structural— in other words, the walls can be rearranged without compromising the structural integrity of the building.
Rather than being embedded in the building structure, the utility lines run straight across the full length of the building. They are clearly visible, making them easier to access for maintenance and upgrades.
The wooden building frame is comprised of a minimal number of relatively large, simple, repetitive members with visible (and therefore more accessible) connections.
Rather than traditional concrete pavement, designers experimented with using concrete bricks that are connected with “tongue-and-groove” joints. This allows blocks to potentially be moved and reused in the future.
BENSONWOOD HOMES, NEW HAMPSHIRE [5]
Bensonwood Homes is a timber-frame company in New Hampshire that designs and builds pre-fabricated houses with “separable layers” (as in the first figure of this blog post).
In a similar manner as the Chartwell School, Bensonwood Homes creates buildings in which the wiring and piping are easily accessible from wall surfaces, and the wood and steel structural members are visible, with deconstruction in mind.
These houses also have both windows and ceiling panels that are relatively easy to remove and replace without damage to the surrounding building components.
THE INTELLIGENT WORKPLACE, PENNSYLVANIA [5]
The Intelligent Workplace at Carnegie Mellon University is a space for office work and research on sustainable building systems.
Like the Chartwell School and Bensonwood Homes, the Intelligent Workplace has utility lines running through the floor and overhead, rather than within the interior walls.
The Intelligent Workplace is a large space with an open plan, interior walls that are stackable and mobile, and a bolted steel frame that is clearly visible to building occupants.
So yes, these projects do exist in the US! But they are rare. Building projects in general require collaboration between many people— building owners, engineers, architects, contractors and subcontractors, real estate brokers, building code officials, a mechanical-electrical-plumbing (MEP) team, and so on. Each of these parties comes in with its own priorities, concerns, and set ways, making it extremely difficult to push forward unconventional ideas, no matter how “good” they may be.
To counter this, it helps to have government support through funding and flexibility in code, public interest, a solid academic knowledge base, and industry-wide enthusiasm. At this moment, these things are not aligned to promote DfD in the US.
But what about outside the US?
BUILDINGS AS MATERIAL BANKS (BAMB), EUROPIAN UNION [6]
BAMB is a European initiative started in 2015 to research and better understand how to make DfD a scalable reality. BAMB involves partners from eight European countries and is involved in some very impressive projects, including Build Reverse in Conception (BRIC)— a project in Belgium, in which different groups of students are guided to construct and deconstruct a single building three times in three years for three different building uses. In 2018, this building was an office building; in 2019, a shop; and presumably in 2020, an acoustic laboratory [7].
BAMB is also involved in a number of other pilot projects, puts together DfD presentations and papers to guide builders far and wide, and hosts an annual DfD design competition for architecture and engineering students, among other things.
CIRCLE HOUSES, DENMARK [8]
Separately, the Danish Environmental Protection Agency and thirty companies from across the Danish building industry have come together for a project called Circle House, set to be completed in 2020 [9]. The concept behind this project was to create a village of sixty general housing units, in which 90% of building materials would be reusable without loss of value. That way, if one housing unit no longer needed a material resource, another unit would be able to claim and incorporate it within its own structure.
OLYMPIC AND PARALYMPIC GAMES VILLAGE, ENGLAND [10]
While designing the London 2012 Olympic and Paralympic Village, the planning committee wanted to ensure that the buildings constructed for the event would be useful beyond the timeframe of the actual Olympic and Paralympic season. The Village was thus designed so that many of its structures would be disassemble-able.
To reduce construction waste and avoid the use of virgin materials, building designers worked to build lightweight structures and use recycled material as much as possible. The post-event deconstruction and demolition process achieved an impressive 98.5% total landfill diversion rate, with priority placed on reuse over recycling. As a comparison, it’s worth noting that some of the top "green" general contractors in California right now are striving for an 80% diversion rate.
This process took two years of planning involving government and non-governmental organizations, the local community, the design team, the construction team, a waste management contractor, material suppliers, and many others.
Notice the difference in approach here: whereas in the US DfD is happening on a project-by-project basis, in the European examples that I have listed out, there is a movement to figure out the system-level challenges of DfD (legal, logistical, financial, etc.) through projects that involve many building units at a time. In Europe, there is an immense amount of cross-collaboration happening across different players in the building sector thanks to government support and industry-wide enthusiasm. And this in turn is fueling public interest and excitement, creating all the more incentive for government and industry to take interest in DfD principles.
Makes me wonder— what would it take to replicate that here in the US?
FOOTNOTES:
A “pre-fabricated” structure is one that has been mostly or partially built in a manufacturing facility before being brought to the project site.
[7] Because 2020 was the year of derailed plans, I am not entirely certain that the project was completed as planned in that year.
[9] Once again, I couldn’t find information on the internet indicating whether this project was actually completed in 2020.
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