With the growth of modern cities and consumer-centric economies, the depletion of natural resources is increasing at an alarming rate. In the coming years, it will become crucial for the design and construction industry to close the loop on the circular economy by designing for disassembly and retrofitting existing buildings for new uses.
Temporary use types are becoming the new standard as tenants cycle in and out, and cities can serve as urban mines for construction materials. Architects must design structures that last for clients who change, and the new normal, strange as it may be, will be designing for impermanence rather than perpetuity. In this blog post, we introduce you to the circular built environment as the new normal in a rapidly urbanizing, resource-restricted world.
Presently, our economy primarily follows a linear model: take, make, dispose. Typically, we construct buildings using predominantly virgin materials. Then, once a building has served its useful life, we demolish it and recycle about 30-50% of the materials, and start the process again. The circular economy, on the other hand, breaks the cycle “between economic growth and increased consumption of natural resources.”1
The circular economy, often described in the context of product manufacturing, is a system "based on the reuse and regeneration of materials or products" that strives to increase their usable life and keep them out of landfills for as long as possible. Not unlike structures that were built hundreds of years ago and still exist, the circular built environment utilizes a more intentional design and material selection process to develop longer-lasting buildings. This approach mitigates the carbon emissions from the built environment, reduces our reliance on natural resources, and diverts construction and demolition (C&D) waste from landfills.
Virgin materials: Upcycling existing building materials reduces our dependency on virgin materials. The extraction of raw materials has many harmful socio-environmental effects, such as degradation of soil quality, deforestation, a significant reduction in biodiversity, and the displacement of people, not to mention carbon emissions.2 The production of cement alone produces nearly three times as much GHG emissions as the airline industry.3
Landfills: Construction and demolition waste is the largest contributor to landfills globally4, with an estimated average of more than 35% of all C&D waste disposed of in landfills annually5. Landfills produce environmental threats including the release of greenhouse gases, leachates, and other waste products into soil, air, and water sources.6 These harmful toxins disproportionately impact marginalized communities.7
Regulatory agencies and recycling: Even with current state regulations and green certifications, a significant amount of construction and demolition waste is still being diverted to landfills. Voluntary green building certifications such as LEED focus mostly on energy use, occupant wellness, and water reduction rather than material reuse. State and local municipalities require projects to recycle and/or reuse C&D waste, but providing the choice allows them to opt for the easier option: to recycle. While recycling building materials does divert the waste stream from landfills, the transportation, processing, and re-manufacturing of recyclable building materials is an energy-intensive process that almost always produces more GHG emissions than the strategy of material reuse.
Designing for disassembly: In order for building elements to be salvageable for reuse, they must be designed for disassembly. Designing for disassembly challenges architects to use "screws and not glues," to separate MEP and IT systems so they can be easily removed, to install modular and prefabricated elements to reduce waste, and to create deconstruction drawings as a manual for the next tenant. If you'd like to know more about designing for disassembly, the EPA has published a detailed guide accessible here.
Example project: Circl (Amsterdam, Netherlands)8
One example of a building designed for disassembly is Circl, a pavilion pilot project in Amsterdam. The project forgoes glues and polyurethane foam for connections that are "screwed, bolted, clicked, or clamped together."9 These connections are easily reversible, simple to access, and detailed in a Disassembly Manual Document for the building.
The project team used an Amsterdam-based firm called New Horizon as their "urban miners," who 'harvest' valuable materials from buildings about to be demolished and supply them to new projects.
Adaptive reuse: Under the adaptive reuse model, buildings last longer, are designed to be renovated and revamped, and end up serving a variety of tenants with a variety of uses. For example, for our project 1305 O'Brien Drive, we converted a defunct OfficeMax distribution center into an award-winning life science complex. If a site requires ground-up construction, architects can design with daylighting, ventilation, and modularity in mind, come the day that the building could be converted to another purpose and continue its useful life. Adaptive reuse can also preserve historical and cultural landmarks, contributing to a sense of place and identity, and creating a more inclusive and diverse urban environment.
Recycling as a last resort: After all other options have been exhausted, some materials will need to be recycled at the end of their usable life-spans — but there are innovative solutions to recycle and reuse these materials back on-site. Cement, for example, the most widely used substance in the world after water, is a significant contributor to CO2 production. Using recycled materials to replace aggregate and cement in concrete does not only reduce CO2 emissions in concrete production, but can also add benefits to the properties of the material. Mixing glass with cement creates a pozzolanic reaction which reduces CO2 and NO2 levels and increases thermal stability. Adding PET plastic as an aggregate makes concrete more lightweight and resistant to corrosion. Tires and rubber, which otherwise have limited recycling capacities, add flexural strength to concrete and protect against fire.10
In a world of rapid densification and urbanization, we are putting an accelerating amount of strain on our natural resources — an amount comparable to the resources of 5.1 Earths.11
In order to sustain our ways of life, we will need to devise innovative ways to work with the limited resources we are given — and without destroying our planet in the process. We must shift the economic paradigm from "take, make, dispose" to reduce, reuse, and — when all else fails — recycle. Stay tuned for our next blogpost where we will talk more in-depth about strategies for designing for disassembly and material reuse!
References:
1 - Zero Waste in Architecture: Rethink, Reduce, Reuse and Recycle
2 - How is Construction & Demolition Waste Recycled?
3 - Concrete is worse for the climate than Flying
4 - Circular Economy of Construction and Demolition Waste
5 - Recycled aggregates from construction and demolition waste towards an application on structural concrete
6 - Modeling Environmental Susceptibility of Municipal Solid Waste Disposal Sites
7 - Addressing the Environmental Justice Implications of Waste
8 - Circl - Case study
9 - The Making of Circl
10 - Circular Economy of Construction and Demolition Waste
11 - How many Earths? How many countries?
With the growth of modern cities and consumer-centric economies, the depletion of natural resources is increasing at an alarming rate. In the coming years, it will become crucial for the design and construction industry to close the loop on the circular economy by designing for disassembly and retrofitting existing buildings for new uses.
Temporary use types are becoming the new standard as tenants cycle in and out, and cities can serve as urban mines for construction materials. Architects must design structures that last for clients who change, and the new normal, strange as it may be, will be designing for impermanence rather than perpetuity. In this blog post, we introduce you to the circular built environment as the new normal in a rapidly urbanizing, resource-restricted world.
Presently, our economy primarily follows a linear model: take, make, dispose. Typically, we construct buildings using predominantly virgin materials. Then, once a building has served its useful life, we demolish it and recycle about 30-50% of the materials, and start the process again. The circular economy, on the other hand, breaks the cycle “between economic growth and increased consumption of natural resources.”1
The circular economy, often described in the context of product manufacturing, is a system "based on the reuse and regeneration of materials or products" that strives to increase their usable life and keep them out of landfills for as long as possible. Not unlike structures that were built hundreds of years ago and still exist, the circular built environment utilizes a more intentional design and material selection process to develop longer-lasting buildings. This approach mitigates the carbon emissions from the built environment, reduces our reliance on natural resources, and diverts construction and demolition (C&D) waste from landfills.
Virgin materials: Upcycling existing building materials reduces our dependency on virgin materials. The extraction of raw materials has many harmful socio-environmental effects, such as degradation of soil quality, deforestation, a significant reduction in biodiversity, and the displacement of people, not to mention carbon emissions.2 The production of cement alone produces nearly three times as much GHG emissions as the airline industry.3
Landfills: Construction and demolition waste is the largest contributor to landfills globally4, with an estimated average of more than 35% of all C&D waste disposed of in landfills annually5. Landfills produce environmental threats including the release of greenhouse gases, leachates, and other waste products into soil, air, and water sources.6 These harmful toxins disproportionately impact marginalized communities.7
Regulatory agencies and recycling: Even with current state regulations and green certifications, a significant amount of construction and demolition waste is still being diverted to landfills. Voluntary green building certifications such as LEED focus mostly on energy use, occupant wellness, and water reduction rather than material reuse. State and local municipalities require projects to recycle and/or reuse C&D waste, but providing the choice allows them to opt for the easier option: to recycle. While recycling building materials does divert the waste stream from landfills, the transportation, processing, and re-manufacturing of recyclable building materials is an energy-intensive process that almost always produces more GHG emissions than the strategy of material reuse.
Designing for disassembly: In order for building elements to be salvageable for reuse, they must be designed for disassembly. Designing for disassembly challenges architects to use "screws and not glues," to separate MEP and IT systems so they can be easily removed, to install modular and prefabricated elements to reduce waste, and to create deconstruction drawings as a manual for the next tenant. If you'd like to know more about designing for disassembly, the EPA has published a detailed guide accessible here.
Example project: Circl (Amsterdam, Netherlands)8
One example of a building designed for disassembly is Circl, a pavilion pilot project in Amsterdam. The project forgoes glues and polyurethane foam for connections that are "screwed, bolted, clicked, or clamped together."9 These connections are easily reversible, simple to access, and detailed in a Disassembly Manual Document for the building.
The project team used an Amsterdam-based firm called New Horizon as their "urban miners," who 'harvest' valuable materials from buildings about to be demolished and supply them to new projects.
Adaptive reuse: Under the adaptive reuse model, buildings last longer, are designed to be renovated and revamped, and end up serving a variety of tenants with a variety of uses. For example, for our project 1305 O'Brien Drive, we converted a defunct OfficeMax distribution center into an award-winning life science complex. If a site requires ground-up construction, architects can design with daylighting, ventilation, and modularity in mind, come the day that the building could be converted to another purpose and continue its useful life. Adaptive reuse can also preserve historical and cultural landmarks, contributing to a sense of place and identity, and creating a more inclusive and diverse urban environment.
Recycling as a last resort: After all other options have been exhausted, some materials will need to be recycled at the end of their usable life-spans — but there are innovative solutions to recycle and reuse these materials back on-site. Cement, for example, the most widely used substance in the world after water, is a significant contributor to CO2 production. Using recycled materials to replace aggregate and cement in concrete does not only reduce CO2 emissions in concrete production, but can also add benefits to the properties of the material. Mixing glass with cement creates a pozzolanic reaction which reduces CO2 and NO2 levels and increases thermal stability. Adding PET plastic as an aggregate makes concrete more lightweight and resistant to corrosion. Tires and rubber, which otherwise have limited recycling capacities, add flexural strength to concrete and protect against fire.10
In a world of rapid densification and urbanization, we are putting an accelerating amount of strain on our natural resources — an amount comparable to the resources of 5.1 Earths.11
In order to sustain our ways of life, we will need to devise innovative ways to work with the limited resources we are given — and without destroying our planet in the process. We must shift the economic paradigm from "take, make, dispose" to reduce, reuse, and — when all else fails — recycle. Stay tuned for our next blogpost where we will talk more in-depth about strategies for designing for disassembly and material reuse!
References:
1 - Zero Waste in Architecture: Rethink, Reduce, Reuse and Recycle
2 - How is Construction & Demolition Waste Recycled?
3 - Concrete is worse for the climate than Flying
4 - Circular Economy of Construction and Demolition Waste
5 - Recycled aggregates from construction and demolition waste towards an application on structural concrete
6 - Modeling Environmental Susceptibility of Municipal Solid Waste Disposal Sites
7 - Addressing the Environmental Justice Implications of Waste
8 - Circl - Case study
9 - The Making of Circl
10 - Circular Economy of Construction and Demolition Waste
11 - How many Earths? How many countries?
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