In summary of my previous post, some defining characteristics of buildings in the US that are “designed for deconstruction” (DfD) are:
Clearly visible structural frames,
Utility lines that have been separated out for accessibility, and
Replaceable wall, ceiling tile, and window systems.
And yes, Europe is doing more. But in any case, “DfD” can’t end at design, because the design itself isn’t what cuts the emissions. The next steps are to deconstruct, to reuse, and consequently to reduce reliance on new building materials.
This can be difficult in practice. When the decision is made to deconstruct rather than demolish, you end up having to plan for a few extra steps:
Executing the deconstruction process safely and efficiently
Managing supply and demand of salvaged materials
Verifying that salvaged materials are safe for reuse
Selling those materials and ensuring their reuse
I think these steps could benefit tremendously from some out-of-the-box thinking and technological innovation, and I’ll suggest some specific examples in the next part. [Please keep in mind that I am not by any means an expert on the topic of deconstruction, and my writing here is a mix of brainstorming and technology I’ve looked into online.]
1. SAFE & EFFICIENT DECONSTRUCTION
Building Information Modeling (BIM)
Buildings with structural members that are clearly visible from the building interior are attractive for deconstruction because they allow deconstruction contractors to better understand what they are working with— in planning the deconstruction process, estimating how much salvageable material there is, etc.
However, a technology called Building Information Modeling (BIM)— which is already commonly used in the construction sector for large projects— can take this a step further. BIM is essentially software that creates blueprints of buildings in 3D.
[1]
BIM software can be installed on tablets and brought onto project sites the same way printed construction drawings are. However, the benefit of BIM is that 3D blueprints make it easier to visualize how the many components of a building (structural, mechanical, electrical, plumbing, etc.) fit together. The virtual aspect of BIM also makes it easier to keep blueprints updated as changes are made, to share information between stakeholders, and to organize the myriad of important details that are traditionally printed on pages and pages of construction drawings.
These same advantages can be applied to deconstruction: a BIM blueprint of a building would allow deconstruction contractors to “see through” buildings and quickly understand where components are in each layer of the building. Having access to this level of detail can facilitate planning and provide a more accurate picture of the outcomes of a deconstruction project before the process has even started.
Taking this further, perhaps a feature could be added to BIM that would enable deconstruction contractors to take notes on which assemblies are easiest or hardest to deconstruct. These notes could then be organized and added to a database for building designers to continuously refine their understanding of what it is that truly makes a building “deconstructable.”
Materials Passports
The concept of “materials passports” works in a similar vein. A material passport is an online repository of key information about a given material. This may include information on material composition, material strength, biodegradability, the material’s effect on indoor air quality, and so on [2].
This is something that already exists to a degree in the form of “Environmental Product Declarations” and other third-party-verified certifications stating that such-and-such product meets a number of pre-set requirements that make it “environmentally sustainable.” But with so many different certifications out there, it can get surprisingly difficult to sort out what information each certification really captures. And with buildings lasting so long, it is quite easy to lose track of the materials in a building once construction is complete.
Instead, what if building components could simply be scanned for this information? Picture something like a QR code, but one that is durable enough to last the lifecycle of a building, cheap enough to print on all or most reusable materials, “dynamic” in the sense that it could be updated by key individuals, and secure enough that the information could not be unnecessarily tampered with [3].
If building components could be scanned in this way, it would be much easier to keep track of information such as the exact source of a given material, the name and location of every project the component was once part of, the remaining lifespan of the material, and the “embodied carbon” associated with the material [4]. Such transparency may on its own incentivize the building industry to take embodied carbon into consideration in daily operations.
Deconstruction-Specific Automated Tools
One challenge currently faced in the realm of deconstruction is a lack of deconstruction-specific tools, and in particular, automated tools. Many deconstruction projects today rely heavily on manual labor, and while this may work for smaller projects, there is no doubt that some tasks could be made more efficient with task-specific automation [5].
To take that a step further, imagine robots that store Building Information Modeling (BIM) blueprints in their memories to optimize the deconstruction process. Imagine if they could scan for and update materials passports, while deconstructing. Imagine if they could automatically tabulate the embodied carbon of an entire building, piece by piece, and notify reuse stores and storage centers of exactly what materials were about to become available... At the moment this all seems like a pipe dream, but it is still pretty cool to think about.
2. MANAGING SUPPLY AND DEMAND OF REUSE MATERIALS
To keep costs low, ideally building components would be transported directly from the deconstruction site of its previous life to the construction site of its next life. This is difficult to pull off in practice because there will realistically be a mismatch between the exact components that deconstruction will free up at a given point in time, and the exact components a construction project will specify within that same time period. I’ve heard that Europe has been addressing this by developing mobile apps that enable construction and deconstruction contractors to communicate a surplus or deficit of specific materials at their job sites.
Yet to capture the wide breadth of materials being accumulated and used across a given region, there will inevitably be a need for storage spaces. The goal then becomes that of minimizing required storage spaces, minimizing transportation distances, and ensuring that the pickup and delivery of materials are conducted in a reliable and cost-efficient manner. Luckily, these capabilities already exist among the thousands and thousands of storage facilities we use for retail every day, so I will not go into the surrounding technology or innovation here.
3. SAFETY VERIFICATION
If a building component is to be reused in a building structure, it is paramount that the component be able to withstand whatever load it is subjected to. Material quality must be 100% certain, because a structure that is improperly designed or built can literally kill. This poses a major challenge for deconstruction and building material reuse, because as important as this step is, very few procedures currently exist for evaluating the quality of salvaged materials.
According to deconstruction expert Brad Guy, researchers in Europe and Canada are currently working to collect data and develop models to re-classify structural steel beams and columns. Based on thorough studies of material type, use patterns, and other factors that affect material deformations and lifespans, it may one day be possible to make reliable evaluations of “reusability” with simple, standardized test procedures [6]. And if it were possible to popularize the reuse of structural members as structural members, reuse could have a much bigger impact in the future than it does now.
After this testing is complete, those materials that do not pass quality control inspections can be reused for non-structural applications (in furniture, interior design, and so on).
4. SALE AND REUSE
To close the loop, these materials need to be sold. To be sold, the materials need to be as attractive or more attractive than virgin materials. The question is, how?
First, there’s the issue of cost. People have asked me what the cost-benefit analysis is like between reuse and business-as-usual construction, but this turns out to be a pretty complicated answer because the cost of salvaged material is contingent on the steps that come before— the deconstruction, the efficient management of supply and demand, the low-cost and reliable quality control— and the vast majority of the US has not even begun to figure it all out. At this stage, reuse is generally expensive because we don’t have the mentality or infrastructure for it.
But there are ways to make reuse appealing so that it can be popularized, scaled up, and made cheaper. One approach to this is to create online procurement platforms specifically for the buying and selling of salvaged building materials at the local level [7]. Like Craigslist, the ideal platform would be so simple and convenient that people would use it just to use it, and not necessarily because they identify as proponents of reuse and sustainability.
Another way to make reuse appealing is to introduce the concept of “design for deconstruction and adaptability” better, and to more people. One technology that could help with this is virtual reality [8]. If virtual reality could be used to get building owners and investors to better understand why separating utility lines from the rest of the structure is helpful to maintenance workers, or better see the difference a deconstruct-able design makes from the perspective of a deconstruction contractor, or better connect the abstract concept of “embodied carbon” with specific building components through a few swipes and clicks, I think it could catalyze the whole building industry into thinking more about the industry's role in climate change.
People are already doing amazing things with technology— making robots dance, having cars drive themselves, etc. The construction sector itself is already experimenting with drones, 3D printing, “smart” hardhats, and so on to promote efficiency, reduce costs, and improve worker safety. Why not take the extra step now and push for innovation with regards to environmental sustainability?
Of course, technology will not be enough to get past the financial, legal, logistical, and cultural hurdles of normalizing reuse. But it has great potential to push the issue forward. For one, better technology would very likely encourage the deconstruction and reuse of large commercial projects, and not just the relatively small residential projects of today. For another, technology gets a lot of people excited and passionate, and both excitement and passion are crucial to change on this scale.
FOOTNOTES:
[1] Image from https://redshift.autodesk.com/bim-interoperability-unified-model-documentation-and-design/
[2] The European initiative Buildings As Material Banks (BAMB) has done quite a bit of thinking on materials passports and has dedicated an entire page to the topic.
[3] Here is a very interesting research paper about printing sensors onto objects, and potential application of this technology in the realm of material reuse. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6387165/
[4] Something else that could be integrated with material passports in the future is blockchain technology— and there are already people out there looking into it.
[5] Having never been on a deconstruction project before, I admit that I am fuzzy with the details on what exactly this automated technology would look like.
[6] This is based on my conversation with Brad Guy on Wednesday, February 10th, 2021 over Zoom. For more, read my other blog posts :)
[7] This is already in place through businesses like ReCapturit and Clear Office!
[8] This is already being put to practice by companies like Dirtt!
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