recycled buildings: how to design for disassembly
Updated: Nov 27, 2019
architecture firms and their clients are becoming increasingly conscious of the environmental impact of their buildings, from life-cycle performance to the economic and environmental costs of dumping quality used components. According to the CDRA, over 500 million tons of recoverable construction and demolition materials are produced in the US each year, including concrete, gypsum wallboard, timber and metals, the vast majority of which end up in a landfill. This month’s feature asks the question—what if we designed for disassembly from the beginning? I speak with Anders Lendager from the Lendager Group, a Danish firm working towards a circular economy by giving upcycled and recycled building materials a new life in their buildings. I also check in with building scientist Bradley Guy, who has been advocating for design for disassembly (DfD) for over twenty years, with the aim to offer outline suggestions for architects to ensure their buildings are ready for the end from the beginning.
The sheer volume of material flowing around the US construction industry is immense—the World Resources Institute estimates that 80% of all materials and minerals in circulation in the American economy are consumed by the construction industry. According to a 2016 report by the Office of Resource Conservation and Recovery, around 70% of construction waste is concrete, the vast majority of which is ground and dumped in landfill sites across America.
While it may seem inevitable that such a resource-heavy industry would necessarily produce significant volumes of waste, according to the US EPA’s most recent estimate, 92% of the waste generated by construction activity in the US each year is the result of building renovations and demolitions, not new build schemes. Might there be a way to design out some of this waste from the start?
Washington DC-based building scientist and associate professor Bradley Guy is convinced that design for disassembly (DfD) is an important tool architects should possess to mitigate the volume and impact of construction waste, not only on the environment, but also on a client’s future financial resources. Guy is one of the few building scientists who has studied deconstruction from both a practical and academic perspective, including unique research into the impact of materials and the time it takes to deconstruct a building using current methods.
By effectively designing for the future reuse, repair and recycling of building components, Guy suggests that architects can make a difference to the volume of waste the built environment generates. “The aim of DfD is the design of buildings to facilitate future change and the eventual dismantlement (in part or whole) for recovery of systems, components and materials,” explains Guy. “DfD offers flexibility, convertibility, addition, and subtraction of whole-buildings. Many buildings are removed from sites due to redevelopment taking place and their inability to remain useful during this process. Instead, DfD is an intelligent strategy to minimize the risk of obsolescence which both makes financial sense for the client and is reassuring for the architect who wishes for their buildings to remain useful”.
Design for disassembly (DfD) offers flexibility, convertibility, addition, and subtraction of whole-buildings.” Bradley Guy
While LEED does not yet give points for design for disassembly in principle, many national green-building rating systems are now rewarding design for deconstruction, including the UK’s BREEAM and Germany’s DGNB. “While some states have adopted the International Green Construction Code as a voluntary addition to the International Building Code, so far the US is not legislating for DfD,” explains Guy. “However, within the LEED system, there is a ‘design for flexibility’ credit for the healthcare sector specifically. Within this credit, there are three recognizable strategies which look to the future of the building as it is being designed. The first is ‘interstitial space’, which means better chase-ways for utilities and services; then ‘softspace’, which is access to unprogrammed space within the building’s shell; and lastly the concept of ‘expansion’, making either future vertical or horizontal extension of core systems viable.”
These innovative strategies are for the most part being driven by the rapidly changing demands of the healthcare sector, and Guy hopes other architectural specializations will soon follow suit. There are currently select other codes which appreciate the end of life impact of buildings, such as material toxicity (which is most stringent in California). In Portland, Oregon, there are now deconstruction ordinance and waste management strategies which focus on the construction industry, suggesting the US may move in a similar way to the rest of the world towards increased regulation of the generation and disposal of construction waste.
It was when Guy worked in skilled building demolition in California, Ohio and Detroit, Michigan that he first became engaged with the volumes of potentially valuable construction waste sent to landfill. “It made me think more about what happens to buildings over time,” Guy explains. “We tracked and quantified everything we disassembled, the costs, the labor and the time it took. We quickly learned that so many elements were impossible to dismantle and had to be disposed of, which was often a dirty job. The people who built these buildings must have thought they would last forever! While there are specific ways to make deconstruction more effective on a detail design level, it became clear that a major barrier is an approach to construction—architects just aren't thinking about the renovation and eventual demolition of their buildings.”
While any type of demolition is a hazardous job, when the materials and construction techniques are not given enough consideration during the design process, or corners are cut on-site, the effects on neighboring communities can be vast, and in some cases, deadly. Reveal recently aired a podcast which touched on the dangers of lead paint in the demolition of old buildings. To save money, water was not sprayed during demolition to mitigate lead dust being released into the air, with far-reaching consequences. “There is no question about the effect of neurotoxins on children,” says Guy, “old buildings can contain lead, asbestos, mercury, wood preservation made from arsenic and cyanide—but worryingly, the chemistry of many of the composite materials architects are commissioning today are more complicated, and can contain harmful pollutants.” To add to this toxicity, for cost reasons components are often glued onsite with environmentally unstable adhesives and resins.
Cradle to cradle design—originating in the product design sector and driven in part by consumer awareness of the economic and ecological impacts of materials used in consumer goods—was popularized in the architecture discipline by William McDonough’s 2002 book ‘Cradle to Cradle: Remaking the Way We Make Things’. The concept is now driving the practice of a select few architecture studios, one of which is the Lendager Group, who set out to become the leading sustainable architecture office in Denmark. Their projects make use of locally sourced and upcycled materials to minimize lost potential within the “construction ecosystem” while adhering to the stringent technical and legislative requirements demanded of any architecture office today.
Lendager Group’s interest in the circular economy originated from their longstanding frustration with the field of sustainable architecture and a desire to change the industry from within. “A problem we repeatedly came up against was that to make a ‘sustainable building’ you needed to add on bits of technology once the design was complete, which was, therefore, more costly for the client,” explains architect and founder Anders Lendager. “This has continued to be a key dilemma for architects wishing to convince clients of the benefits of sustainable design. Our view is that innovations need to instead occur within the design process, which for us means rethinking how that process is carried out altogether.”
The Lendager Group call themselves a “nexus” organization as they consist of three separate businesses, each working towards the shared goal of making a circular construction economy a reality. The first workgroup is referred to as a “strategic management consultancy”, the second an architecture studio (further subdivided into working groups with either a building or urban scale focus) and the third is centered around material research and innovation, working to create and upcycle products for use in their buildings. This unusual multi-disciplinary business model enables the Legander Group to maintain control over and ensure their architectural solutions can meet their own sustainability standards, including the reduction of CO2, water usage and toxicity.
“The question we are asking is—what can inspire architecture to develop answers to climate change and wider geopolitical questions through local solutions?”, asks Lendager. “Unfortunately in our society we have chosen to construct buildings where short turnaround and low upfront costs are the two most important factors. But the reality is that approach generates way higher costs later down the line, both financial and environmental. When buildings are deconstructed, their component materials may not be at the end of their lifespan, which generates massive wasted potential. It was not until we started to make material catalogues of existing sites that we realised the true value of the materials about to be scrapped,” Lendager continues, “so made it a key goal for our office to harvest this material potential, which we call the ‘tax’, or ‘data’, held in the beams. That is why we developed our consultancy wing, to lay the groundwork for the technical challenges, such as fire and building regulations, to find new ways to handle the demands and the legislation of how to take things apart”.
The Lendager Group’s Reuse Station project, a local recycling center built in the Copenhagen district of Nordhavn, aims to challenge the public’s conception of waste to instead consider it as a resource for construction. “We wanted to show that everything in the project could be made of waste from the local area. Perhaps understandably, the Municipality thought we were crazy,” recalls Lendager. Yet, when they began to organize the waste materials into piles of the same type, they found that perceptions shifted. “When we had collected 1000 bottles, people started to see a potential resource”, says Lendager. While the Group pushed to have upcycled plastic tubes in the project, they settled for recyclable tubes, instead creating a take-back agreement between their consultancy wing and the subcontractor who provided the tubes.
Lendager group believes that for design to be sustainable it must also be commercially viable, a concept which is explored further in their upcoming Circle Houses project. The ambition behind Circle Houses is to create a design in which the components of each house can continually be reused. “Rarely can buildings be taken apart for direct reuse,” explains Lendager, “designing architecture with accessible joints so that they can be disassembled—we’ve kind of forgotten that was possible.” Circle Houses aim to achieve DfD by minimizing core components and making use of deconstructable joints. The result is reflected in the architectural tectonics of the project, which Lendager terms “ornamentation”. “We aim to be thinking of the next five projects these materials could construct while we are designing”, suggests Lendager, “if a building can only be assembled as itself, there is an inherent loss of potential.”
This construction approach has been written about by Guy in his design for deconstruction checklist, and he has noted that certain projects and architectural movements have accommodated DfD, despite not generally recognized as doing so. For example, the Seagram building in New York by Mies van der Roche makes use of pure materials, such as metal, glass, stone and concrete in its detailing, which offers future opportunities for direct recycling and reuse. In his research, Guy underlines that the use of connections such as bolts as “key ingredients in Modernism” as a valuable “potential deconstruction tradition”.
In turn, Guy suggests the high-tech style of architecture, which includes the work of Richard Rodgers and Renzo Piano, also demonstrates core DfD principles. “These designs turn the traditional layers of internal core mechanical and utilities systems inside out, using structure as an armature upon which to place mechanical, plumbing and electrical systems, these designs provide for open flexible floor plans within the envelope of the building. As a matter of course, DfD is also integral to contemporary exhibition pavilions, entertainment structures and military facilities used for rapid deployment and temporary use. While these may be the most prevalent examples of current DfD practices, they can provide valuable concepts for the design of more permanent building types.”
Prioritizing DfD within the architectural design process has numerous clear advantages, such as the support of component recycling, lowered embodied energy and ecologically sound material production methods, (which also offer better indoor air quality during the working life of the building), alongside enabling the design to adapt to multiple programs, technological updates and physical configurations over its lifetime. But there are also key drawbacks with a DfD approach in the construction industry today which Guy notes in his research. For example, there are general trends away from the craft skills required to create exposed connections and details, instead favoring pneumatically driven nails, staples and adhesives which take an excessive amount of time to deconstruct, often leading them to be scrapped. He also makes note of an increased use of composites and engineered products which are difficult to recycle because of their chemical complexity. Both trends are driven, he suggests, by the “the highly speculative nature of most building, whereby there is not a long-term ownership, and therefore adaptation, renovation and demolition costs are not borne by the original owner.”
However, Guy sees DfD as a beneficial tool for architects working today, and in the future, as he believes architects still have the opportunity to take on the role of arbiter for the other subcontractors and the capacity to influence what is economically and ecologically the best decision for their clients. While the construction industry is unlikely to change overnight, there are some small steps any architect or designer can take to ensure they are thinking about how their building performs both during its usable life and when it no longer is useful. As an outline guide, I have organized these into ‘structural strategy’, ‘careful material choices’ and ‘designing the details’. Read Guy’s design for deconstruction checklist in full here.
It may seem obvious, but to ensure the building is prepared for future disassembly, architects should be involved with structural design from the beginning of the project and stay engaged throughout the design process. If appropriate, the structural framework should be adaptable to ensure the working life of the building is as long as possible. How can your design be more adaptable as people’s needs change? Is it designed for ease of maintenance, without mechanical elements that are easily broken over time?
“Depending on your project type and client’s needs,” suggests Guy, “offsite construction and prefabrication may be useful systems as they bring the architect closer to the construction process. However, this may not be what it first appears on the surface as often modular buildings are not easy to transport due to the stress of moving them on a truck leading to breakages, which are often solved with adhesives.” Perhaps there is a better way to design modular construction components so that they can withstand shocks, for example, panel constructions assembled onsite?
careful material choices
When specifying materials, consider their toxic legacy—are they high quality? Robust? Easily reusable or recyclable? To some extent, corporate clients are driving a market shift here due to their desire to promote a ‘green image’ for their companies. “Architects need to know all the materials they are commissioning in the building,” Guy suggests, “and the trick is to begin a strong discussion with the contractors as early as possible, as most of the design and construction costs are predetermined in the initial phase of design.” In my own practice, while I have some reservations about the use of BIM, I have noticed some 3D modeling tools can assist in this regard as they are able to generate automatic component schedules, emphasising the nature and quantity of each material in the design. Certain add-ons for BIM programs can also now estimate the embodied energy of different design options.
designing the details
“It is important not to leave this up to the contractor,” stresses Guy, “and instead take detail design into your own hands if you wish to design for disassembly. It is important that whoever is taking the building apart needs to be able to access key structural connections”. Lendager agrees, “the two most important things for architects to bear in mind when they are designing is both component disassembly and material disassembly. Component logistics need to be a driving part of the design to create a truly sustainable building. This means understanding the 1:1 details of how it would be constructed, as an integral part of your work methodology. In turn, you need to consider the endurance of your materials. Bricks are very reusable and can withstand over 400 years, being ‘upcycled’ in many, previously unimaginable ways. That makes it an intelligent system.” As a rule of thumb, Guy also suggests no concealed connections and use standard steel and timber lengths where possible.
Rather than being about a specific construction technique, or architectural style, design for disassembly might be seen as a process of developing practices and assemblages to get the most use out of building materials while maximizing opportunity for repair, reuse and recycling further down the line. Guy suggests, “the next generation of buildings will have to express more intentionality of the continuous material cycle if they are to be sustainable in the long term.” He predicts that in the US, the school and healthcare building sectors are in a position to engage with and push for DfD as indoor air quality and longevity are at the forefront of their client’s, and public, concern.
If the costs of landfill and the production and imports of virgin materials continue to increase it seems likely that DfD will also play a larger role in commercial architecture sector in the next decades. Thirty years from now will the building you are currently working on still be standing, or will it be a hazardous addition to a landfill site? Will the materials you have specified stand the test of time and will their parts take be repurposed into a typology yet unimagined?
This article is from a monthly feature column ‘Architecture Futures’ for the online platform Archinect which explores architectural developments within wider cultural and political discussions. Read the original article here: https://archinect.com/features/article/150067785/recycled-buildings-how-to-design-for-disassembly