What three 2013 climate-related events have left us with $53 billion in damages? In addition to the enormous dollar amounts they racked up, the Tasmanian bushfires, Hurricane Sandy, and the EF5 Oklahoma tornado, together, left thousands homeless. Lives and the economy were disrupted. And that’s just the beginning of the droughts, heat waves, and super-storms that experts predict for the near future.
Our species has survived on Earth for 200,000 years. Yet, we are babies compared to 3.8 billion years’ experience of other living organisms. So as we struggle to be resilient, why not ask the species that, for eons, have been able to manage the same challenges? Let’s ask ourselves this: “What would nature do?”
The Genius of Biome report starts this conversation. How does nature design resilient forests to manage windstorms? What does nature do when faced with catastrophic disruption?
One example of amazing resilience in nature is the story of the American chestnut tree. The species once formed 25-50% of the temperate broadleaf forest canopy in the northeastern U.S. A major source of food for hundreds of species, the chestnut disappeared from this ecosystem 40 years after a new fungus, imported on non-native trees, arrived on the continent.
In the 1940s, when the chestnut trees died, the forest canopy opened up, the food web deteriorated, and soil erosion ensued. However, many tree species in those forests were not susceptible to the fungus and were also abundant food producers and soil stabilizers. Oak trees, sugar maples, serviceberry, and black cherry have now replaced the American chestnut and serve as primary food sources for forest creatures. A dense understory took over, assisting in soil stability. This catastrophic biological event was resolved because of the redundant functional roles existing in the community of species in the ecosystem.
How can we emulate this redundancy principle? We, too, experience catastrophic events that destroy our built environments; what could we do to foster resilience?
Architecture is a human act that invades and displaces the natural ecosystem. Biological order is destroyed every time we clear native plant growth and erect buildings and infrastructure. The goal of architecture is to create structures to house humans and their activities. Humans are parts of the earth’s ecosystem, even though we tend to forget that.
Logically, architecture has to have a theoretical basis that begins with the natural ecosystem. The act of building orders materials in very specific ways, and humans generate an artificial ordering out of materials they have extracted from nature and transformed to various degrees. Some of today’s most widely-used materials, such as plate glass and steel, require energy-intensive processes, and thus contain high embodied energy costs. Those cannot be the basis for any sustainable solution, despite all the industry hype.
Resource depletion and a looming ecological catastrophe are consequences of detachment from nature, and a blind faith in technology to solve the problems it creates.
Architectural theory, in the sense understood in this course, is a framework that studies architectural phenomena using scientific logic and methods of experimentation. Many experiments have been done by others, and we are going to apply them to architecture. Theory provides a model that explains investigations and observations about form and structure.
A successful theory will help us interpret what an architect does, even though each architect will likely have his/her own motivation and explanation. Nevertheless, the theory will allow us to compare among different types of buildings, and to evaluate how well those connect to users and with nature. We can understand how a building came about, and how it connects and interacts with its surroundings.
It will also be good if common people, not just architects, can understand architectural theory, and thus it should be formulated with that goal in mind. The advantages are that it is ordinary people who are going to inhabit those buildings, whereas architects can choose to live and work wherever they like. Another crucial point is that the majority of building activity is, and has always been, the erection of self-built informal settlements. People, not architects, build these structures.
Christopher Alexander has pioneered a theory of human-made order. It is based directly upon natural order, so there is neither contradiction nor confusion between the two types.
Alexander made five key assumptions that permitted him to pursue his work.
(1) Natural and artificial order rely upon the same mechanisms for their working.
(2) Natural order is self-organizing and self-correcting. What we observe is there because it works.
(3) Artificial order is not necessarily self-correcting, or maybe it is on a generational timescale so individuals are not going to notice it. As a result, human beings can do things to the natural environment and build buildings and structures that damage the world. It is not easy to diagnose what is good and distinguish it from what is bad.
(4) It is possible to use science to create diagnostic tools for what is good and bad in human creations — in how they affect the natural environment, including us humans.
(5) We can use the human body as a sensing instrument for what is good and bad in architecture. Basic assumption: human feeling is universal, and people share 90% of their responses, even if individuals come from different cultures or backgrounds.
To make good buildings, we need a worldview, a conception of the world that is healthy and that enables us to understand things deeply. A healthy worldview is based upon connectivity to the world: direct connection to the order of the universe and to natural processes as they are continuously occurring.
Transformations of the PIazza San Marco in Venice that preserve structural wholeness over about 200 years, part of a larger series over 1,000 years as shown by Christopher Alexander in his book, “The Nature of Order”. Image Courtesy of Nikos SalingarosThe opposite — detachment — leads to a dangerous condition where people analyze a situation as a mechanism isolated from the world. This is the model of a building or a city as a machine. Modern science is guilty of contributing to this disconnection from nature, since scientific models are necessarily self-contained and limited in scope — otherwise they would be useless.
Science gives us an excellent model of how something works as a mechanical system. Nevertheless, this is not a complete description even of the cases we do understand well. And there are a vast number of instances where we ignore any mechanical description at all of an observed phenomenon. What is completely missing from a strictly mechanistic worldview is human consciousness, our personal and emotional connection to the universe. This might not matter when investigating some technical problems, but it’s all-important for things that affect us, like architecture. Another significant consequence is the lack of value in a mechanistic worldview. A human connected to the universe knows the distinction between good and bad, true and false, beautiful and ugly. These qualities are not relative, and are not matters of opinion. A consumer disconnected from natural values, by contrast, can be fed toxic products and be made to believe they are good.
The way out of the present, highly restricted view of the universe is to develop an immensely more connected state between humans and their environment. Attention is given to what affects us reciprocally with the world, when we are tightly connected.
Following this reasoning, people have a shared basis for judgment, and can intuitively judge whether something has order or life, and expect their gut reaction to be 90% shared across cultures and distances. In this new worldview, ornament plays a critical role to connect humans with the order of the world. Ornament is thus intimately related to function in the non-mechanistic sense.
We wish to consider architecture and the production of human artifacts also as essential components of natural ecosystems. Order and life are related. Natural things have an intrinsic order, and life as we usually know it and understand it is simply an extension of that order. For this reason, human constructions should not damage or contradict natural order.
The earth’s ecosystems (many of which are connected to each other) contain, and are contained by other components that neither metabolize, nor replicate. But every layer of the system is interdependent. This property of life in inanimate objects and situations arises out of their degree of natural order, and the human body has evolved mechanisms to sense that order. Thus, it is not surprising to feel that something is “alive”, because of its geometrical properties, even though that object is not biological.
Biological organisms have the additional features of metabolism and replication. A very simple consequence of thinking of a building as a “living” entity is that it requires repair and restoration. This analogy with metabolism takes us away from a central tenet of 20th Century industrial architecture: the quest for absolutely permanent and weather-resisting materials. This search has become very expensive. But worse of all, it denies living qualities. Materials that do weather in fact produce buildings that are more in keeping with biological organisms. For example, the Ise Shrine Complex in Japan is re-built every 20 years.
The Ise Shrine: Deconstruction. Sketch by Miller Yee Fong, Architect. Image Courtesy of The Huffington Post
Buildings also engage in replication: if a form language is adopted by other builders, then the original prototype building is replicated in more copies, not exactly the same, but containing the same “genetic” information.
Since the perception of something as being “alive” is due to a very strong connection with our mind and body, there is a reciprocal effect: that object, place, or configuration makes us feel more alive. It is possible to find myriads of artifacts, buildings, urban spaces that feel “alive” and that in turn make us feel “alive”. They invariably come from vernacular traditions and hardly ever from design. The perceived living quality comes from specific geometrical configurations, and it is possible to discover the rules that generate a living quality. Even in non-traditional 20th-century examples of objects and places having perceived “life”, the life comes from their geometry. It is not based on concepts, or images, or fashions. By connecting to the thing, we feel that we are connecting directly with its maker, who therefore doesn’t hide behind any notions or ideas that contaminate its genuine character.
To get at a genuine understanding of architecture, it is useful to use the approach that scientists employ to discover nature’s secrets.
Edward Wilson outlines what science achieves:
(1) Systematic gathering of knowledge about the world, which is organized and condensed into basic principles as far as possible.
(2) Results must pass the test of independent and repeated verification.
(3) It helps to quantify information, for then, principles can use mathematical models.
(4) Condensation of information via systematization and classification helps in storage.
(5) A safeguard for truth comes from consilience: the horizontal links across diverse disciplines.
Consilience acts as a test for the soundness of a theory. Within itself, a theory might look good even when it contains fundamental flaws. Internal consistency can be misleading, since it could relate several false assumptions, but in a very convincing manner. We normally should be able to transition from one sound theory into another one that acts on a distinct domain. If there is a contradiction, then something is wrong. It could be that there is no barrier but a large gap, in which case that needs to be filled in.
Architectural theory can be formulated and verified by employing two mechanisms: internal hypotheses that are repeatedly verified, and external consilient links to other disciplines that have a verifiable basis. These include the hard sciences.
Good architecture is less of a reductionist discipline and must necessarily be a synthetic discipline. If it is applied in a reductionist manner, then it probably contains serious errors that damage the environment. To be adaptive means to synthesize many distinct responses to human needs and natural order.
Most important is for architecture to be directly linked to human evolution, the physical needs of the organism, and to use information according to evolved culture. Neglecting the biological origins of human needs and behavior detaches architecture from the world and from humanity. The architect should design a building that makes common people feel comfortable, and not to be liked just by architects. It should also adapt to its locality, not designed for somewhere else, or for no place in particular.
The fractal pattern of self-organizing urbanism. Image Courtesy of Nikos Salingaros
Further Reading:
Christopher Alexander, The Phenomenon of Life, Prologue & Chapter 1, “The Phenomenon of Life” (Center for Environmental Structure, Berkeley, 2001).
Nikos Salingaros, “Architectural Theory”, extracts from Anti-Architecture and Deconstruction (Umbau-Verlag, Solingen, 2008).
In KieranTimberlake's extensive survey of roof gardens, it identified species that were planned, had thrived, or were rogue (l to r, respectively): prairie dropseed (Sporobulis heterolepsis); two-row stonecrop (Sedum spurium fuldaglut); moss pink, pink phlox (Phlox subulata) Credit: Bruce Peterson
It’s one thing to Photoshop a green roof into a rendering; it’s another thing to plant and sustain one. And it’s all but unheard of to go back and analyze the state of these living roofs years after their completion, as Philadelphia-based Kieran Timberlake did for its groundbreaking Green Roof Vegetation Study. The study responds to “a lack of long-term data on real buildings with diverse and dynamic plant communities,” according to the firm. Instead of concentrating on one engineering or horticultural aspect of green roofs, the firm looked at “how green roofs function as ecosystems and how they change over time.”
The jury highlighted two innovative aspects of the study: its comparative method and its ecological thesis. In 2011 and 2012, Kieran Timberlake surveyed six of its completed green roofs, ranging in area from 1,744 to 10,000 square feet, and designed between 2003 and 2011. Using the Relevé vegetation survey method and the Braun-Blanquet abundance scale to quantify its findings, Kieran Timberlake assessed the roofs’ vegetative cover, species richness, and species diversity in 2-meter-square sections. The researchers also interviewed facilities and grounds maintenance personnel at each site. Juror Bill Zahner praised the study’s “way of collecting the data needed rather than saying, ‘Well, let’s just put seeds down and keep our fingers crossed.’ ” Juror Jing Liu agreed: “What they’re doing is different. The research is to study the long-term dynamics of green roofs.”
The resulting report confirms that roof ecologies are indeed dynamic and that changes will occur spatially and over time from the original planting design. More importantly, it details the nature of those changes, and raises questions about what the changes might indicate for long-term resiliency. In many of the case studies, the prevalent species observed on the roofs in 2012 that were part of the initial planting design were accompanied by dozens of new or “emergent” species. Artemisia (commonly known as mugwort) at the Yale Sculpture Building and Melilotus (or sweet clover) at Cornell University’s Alice H. Cook House independently found their way to roof tops, took root, and eventually made themselves at home in the roofscape design. Roof biodiversity often increased, although the report cautions that the results of any single survey could be deceptive: “What appears to be major shifts in species composition may in fact be short-term fluctuations or cycles caused by unpredictable changes in experienced climate and environmental conditions.”
While the report rigorously maps the distance between design intent and material outcomes, it also sets the stage for even more radical research to be conducted on the interplay between landscape and architecture. Kieran Timberlake envisions deploying sensors on the roof to measure thermal and moisture conditions in relation to the building’s internal climate and energy consumption. The report also suggests that architecture “is responsible for the … vegetative dynamics and ultimate performance of the roof.” On the roof of a dining hall at Middlebury College, for example, the otherwise feeble grasses and forbs become lush and verdant around the skylight cones, whose shade presumably helps the soil retain moisture. “Architectural design creates microclimates across a roof, determining availability of sunlight, water, and nutrients,” the report states.
Kieran Timberlake is already putting its newfound knowledge to use on the forthcoming Penn State Center for Building Energy Education and Innovation at the Philadelphia Navy Yard, which itself will serve as an ongoing laboratory and teaching center for scientists, students, and professionals interested in eco-effective architecture. The firm has developed a proposal to create a green roof test bed on this building; currently, it is in the process of raising funds.
But documenting the consequences of a designed green roof subjected to unforeseeable or uncontrollable environmental forces has wider implications for architecture in general, juror Jing Liu said. “If you think of the green roof as an ecological system, you can have architecture as an ecological system,” she said.
In the messiness of the real world, architecture depends on dynamic variables. Buildings are never really complete. Rather, they are subject to the vicissitudes of client maintenance regimes, the inconsistencies of occupant behavior, and the unpredictability of weather. That is why post-occupancy studies—of both indoor and outdoor environments—must be as meticulous as they are fearless.
Project Credits Project Green Roof Vegetation Study Design Firm KieranTimberlake, Philadelphia Project Team Roderick Bates, Stephanie Carlisle, Billie Faircloth, AIA, Stephen Kieran, FAIA, Taylor Medlin, Assoc. AIA, Max Piana, James Timberlake, FAIA, Ryan Welch
In 2005, when Kieran Timberlake planned the green roof of Cornell University’s Carl L. Becker House, in Ithaca, N.Y., the rigorous planting plan comprised three types of succulents (two-row stonecrop, tasteless stonecrop, and houseleeks), combined with strips of prairie dropseed. When Kieran Timberlake surveyed the roof in 2012, the vegetation was healthy and full, but there were a few surprises—54 of them, in fact. That is the number of new plant species that had taken root over the years.
An aerial view of Cornell campus dormitories shows Kieran Timberlake's green roofs outlined in white; the Carl L. Becker House is at the right side of this image. Credit: Kieran Timberlake
According to KieranTimberlake's study, the most biodiversity was found in the Becker House's southernmost bay, where shading along the adjacent building edge minimized the effects of record droughts.
Various poplar species were found on the Becker House roof, despite not appearing in the original roof planting plan.
Can you imagine a house powered not by sun, wind or coal, but by living algae? A group of graduate students at the University of Cambridge can … and their idea has won them international recognition. Practising what they call “algaetecture,” the students designed an “Algae House” they say could provide a model for future energy-efficient living. In such a model, the house’s residents would get the energy they need from the hydrogen and bio-mass created by the cultivation of algae.
The Algae House design, created by graduate students in the university’s Departments of Architecture and Engineering, was awarded first prize in an international design competition run by SASBE2009 — the third CIB International Conference on Smart and Sustainable Built Environments. The competition challenged students to propose a concept of a small home that produces enough sustainable energy to equal out energy consumption.
The Cambridge team’s winning design uses in-built algae tubes and a photo bio-reactor to generate hydrogen. A glazing system and water pool are incorporated into the design to mitigate — reflect and cool — the sunlight the algae need to thrive. According to the students’ estimates, the house would produce 4,100 kilowatt-hours of hydrogen and bio-mass per year — enough to drive an electric MINI E car from London to Beijing and back twice over .
“Algae and people may not present themselves as obvious bedfellows, but through this project we hope to show that the integration of algae as an energy generator within a house is not only feasible, but that it opens up many exciting architectural possibilities for green living,” said Karuga Koinange from the Department of Architecture.
The competition, held at Delft University of Technology in the Netherlands, was organised and sponsored by the International Council for Research and Innovation in Building and Construction (CIB), the Passive and Low Energy Architecture association (PLEA) and the International Initiative for a Sustainable Built Environment (iiSBE). The students presented their work throughout the week-long proceedings to a variety of conference attendees, including the Dutch Crown Prince, Willem Alexander.
By John Thackara Authors Note: For an exhibition that has opened in The Hague called Yes Naturally I was asked to contribute a text for the bookabout what nature might mean for cities, and vice versa, in the near future. Here is an extract.
The writer Thomas Berry described the ecozoic as the “reintegration of human endeavours into a larger ecological consciousness”. The ecozoic, Berry believed, would supplant the Anthropocene age, that we live in now, in which human needs take precedence over the health of the earth’s forests, oceans, and other living systems. Our species will only begin to make true progress, Berry believed, when we learn to cherish the vitality of all life-forms equally — not just our own.
Berry’s ideas could be dismissed as charming, but implausible — were it not for many small signs that just such a cultural shift may be brewing underneath the shiny surface of business as usual.
Over the ages we’ve invested huge amounts of effort and energy to keep cities and nature separate. The intensity of that effort was obscured until, in 1971, a geologist called Earl Cook developed a technique to measure the energy ‘captured from the environment’ in a modern city. A hunter-gatherer 10,000 years earlier, Cook reckoned, got by on 5,000 kilocalories a day. A New Yorker or Londoner today, by contrast, needs about 300,000 kilocalories a day once all the systems, networks and gadgets of modern life are factored in. That’s a difference in energy needed for survival, between lives that were part of nature, and lives lived apart, of60 times — and rising.
Paving over the soil, and filling our lives with media, obscured our interdependency with living systems for a centuries. Now, as awareness of energy precarity grows, so do nagging questions about the ways we think about, and inhabit, our cities: How much energy does that skyscraper use each day? what level of resources are embedded in that flyover? What was it like here, before we paved it over?
In 2009, the Mannahatta exhibit began to answer that last question. It exposed New Yorkers to Manhattan’s ecosystem in 1609 — just before the first settlers arrived. Today’s city of asphalt and skyscrapers, it turned out, was once a diverse and life-filled landscape. Times Square was once a forest. Harlem was a meadow. A landscape of forests, fields, freshwater wetlands, salt marshes, springs, ponds and streams was home to bears, wolves, songbirds, and salamanders. Clear waters jumped with fish. Porpoises and whales were at home in the harbor.
Mannahatta’s curator, the landscape ecologist Dr. Eric Sanderson, was not intent on returning New York to its primeval condition — but he did hope that the show would sensitise New Yorkers to the living systems that continue to support their city. And a question was posed: Could these hidden ecological functions be relevant to the city’s future development?
A growing worldwide movement is looking at cities through the lens of living systems. In countless practical projects, city dwellers are re-connecting with the soils, trees, animals, landscapes, energy systems, water, and energy sources on which all life depends.
For the moment, this movement is mostly bottom-up, small-scale, and low-budget. It’s a barely visible mosaic in which rivers are restored by volunteers, car parks are depaved by activists, trees are planted by community teams, rainwater is harvested by neighbours, gadens are tended by school students, and nesting boxes for birds are installed by twitchers.
A lot of this work is carried out by community groups working street-by-street. As more small projects are completed,the to-do list expands. People notice that there are neglected parks to transform, gardens to revive, roadside verges to plant, empty roofs to green. There are vacant lots, abandoned buildings and empty malls to put to new use.
The fact that most of these actions are small does not diminish their significance. Change bubbling up from the bottom is how complex systems change — and cities are no exception. Besides, this proliferation of green shoots creates new work for for city managers and policy makers to do: Nurturing these thousands of tiny patches, removing obstacles, linking them together.
A startling question begins to be heard: Pull that weed out of its crack in the sidewalk — or let it grow?’
A growing number of people are inclined to welcome back the weeds in the cause of biodiversity. It turns out that there is more biodiversity in many cities than outside them. The lesson here is that cities, and not just rain forests, can provide ecosystem services when they are filled with plants and trees. When researchers in the UK visited parks, golf courses, abandoned warehouses and household gardens around the city of Leicester, they discovered that urban vegetation stores ten times more carbon dioxide than previously assumed.
Private gardens, too, have enormous potential to act as archipelago-like nature reserves for pollinating insects, whose populations have been plummeting across the U.S. and Europe. The UK’s 15 million backyard gardens cover about 270,000 hectares — more than the all the country’s official nature reserves combined.
Seattle’s Pollinator Pathway Program links together urbanism, farming and wilderness recovery in a connected whole. The artist and ecological designer Sarah Bergmann coordinates with citizens, urban planners, engineers, and parks departments to replant and connect small areas of public and privately owned urban land; the resulting corridors mimic the healthy systems commonly found in rural and wild environments. Each planting strip — usually a band of grass between sidewalk and street — is transformed into a pollinator-friendly garden that offers viable food and habitat to vitally important insects. Fifteen Pollinator Pathway gardens are now in place on Columbia.While motivated in part by concern for honeybee colonies, the project takes a long term perspective on support for regional food systems and emphasises support for a variety of native pollinator species and their favourite plants.
The English writer Richard Mabey was one of the first to suggest that the concepts of ‘urban’ and ‘rural’ no longer apply. In The Unofficial Countryside, first published in 1973, Mabey describes his explorations of crumbling city docks, railway goods yards, sewage farms, and disused factory wastelands. He tells of his realisation that even the most unpromising, blasted and neglected urban landscape is capable of supporting life. “A crack in the pavement is all a plant needs to put down roots” Mabey recorded; “provided it is not actually contaminated there is scarcely a nook or cranny anywhere which does not provide the right living conditions for some plant or creature”
Many of these plants turn out to be edible. Herbal fruits, leaves and edible flowers grow on walls and roadsides, between paving stones, and in other untended spaces.
Urban biologist Claudia Biemans, an edible plants researcher in The Hague, identified about 300 different species in one square km of her city compared to 50 different species found in the same area of industrially-farmed countryside nearby. “Bees know this very well, and are more to be found in cities these days” she points out. On walks called ‘Stalking The Wild’, Biemans guides people to ecological niches in the city where plants don’t just survive, but thrive. Lynn Shore in Amsterdam, trading as Urban Herbology, is among a growing band of urban foragers who help citizens find herbs, use them in cooking, and learn about medicinal preparations. Shore’s activities include seed and plant swaps, urban herb walks, and ‘gatherings for urban herbies’.
In Los Angeles, a so-called ‘rock star of foraging’ called Pascal Baudar has turned foraging into a thriving business; Angelinos pay $100 a head to join his ‘Gourmet Foraging Sunset Experiences’ in which they learn about the culinary uses of weeds found in the local landscape. Baudar’‘s wild food classes sell out weeks ahead.
Less prosperous foragers — the majority — are using a free mobile phone app called Boskoito map the edible landscape; they share the location of wild-food in public spaces in an activity called ‘augmented foraging’.Boskoi, say its Dutch developers, combines the ancient knowledge of hunter-gatherers with today’s mobile technology. The word Boskoi, which is taken from Greek, dates back to the tradition of desert hermits the South Egyptian and Sudanese desert. This hardy band survived exclusively on wild herbs and rainwater, and were said to graze with wild herds of cattle.
Scientific researchers, following in the steps of these ecological artists, are unearthing plants and animals that are unique to cities — from mice and fish, to bugs and bacteria. In New York, scientists have identified mutations in more than 1,000 genes in the city’s mice — far more than than are found in mice from out of town. Not all change has been positive for biodiversity, of course: Manhattan was once home to 21 native species of orchids; these are now all extinct due to the replacement of woodland by open urban spaces.
Or are they? Their seeds may still be there. The notion that older ecologies lie beneath our cities, just waiting to self-resurrect, has long fascinated artists – and now scientists, too. Paleobotanists have discovered that ten square feet of urban soil can contain tens of thousands of dormant seeds. In his essay ‘City of Seeds’, the writer Daniel Mason reflects that,unlike the managed green of parks and gardens, which only grow in pockets of protected isolation, the wild plants of a city need “the cracks, the pavement split, the palace abandoned”. Beyond the managed gardens and the wild invaders of our roads. Mason concludes, is “a hidden, potential flora, an idea of a forest, not in competition with the city but existing alongside it, patiently, waiting to become manifest”. http://changeobserver.designobserver.com/feature/the-ecozoic-city/37765/
"I am seeking for the bridge which leans from the visible to the invisible through reality."
Max Beckmann
India's Meghalaya state region has a cultural tradition based on adapting and surviving in a radical environment: They train the roots of trees to grow into sustainable bridges that will adapt and grow over 500 years to create natural traverses for humans and will survive the torrential rains common in the region. A great example of living architecture from which we will should be inspired.
Scientists at a Spanish university are developing a new type of concrete that captures rainwater to create living walls of moss and fungi. Unlike existing vertical garden systems which require complex supporting structures, the new "biological concrete" supports the growth of organisms on its own surface, according to researchers from Universitat Politècnica de Catalunya in Barcelona.
The concrete contains a biological layer that collects and stores rainwater, providing a moist growing environment where microalgae, fungi, lichens and mosses can thrive, they explain in a report. A waterproof layer separates the organisms from the inner structural part of the concrete, while an outer layer acts in reverse, allowing rainwater in and preventing it from escaping.
The concrete also absorbs carbon dioxide in the atmosphere and acts as an insulating material and a thermal regulator, say the researchers, who are currently in the process of patenting the material. The next step is to accelerate the process so that the mossy surface develops in under a year, they add.
Researchers at the UPC develop a biological concrete for constructing “living” façades with lichens, mosses and other microorganisms
The Structural Technology Group has developed and patented a type of biological concrete that supports the natural, accelerated growth of pigmented organisms. The material, which has been designed for the façades of buildings or other constructions in Mediterranean climates, offers environmental, thermal and aesthetic advantages over other similar construction solutions. In studying this concrete, the researchers at the Structural Technology Group of the Universitat Politècnica de Catalunya · BarcelonaTech (UPC) have focused on two cement-based materials. The first of these is conventional carbonated concrete (based on Portland cement), with which they can obtain a material with a pH of around 8. The second material is manufactured with a magnesium phosphate cement (MPC), a hydraulic conglomerate that does not require any treatment to reduce its pH, since it is slightly acidic.
On account of its quick setting properties, magnesium phosphate cement has been used in the past as a repair material. It has also been employed as a biocement in the field of medicine and dentistry, indicating that it does not have an additional environmental impact. The innovative feature of this new (vertical multilayer) concrete is that it acts as a natural biological support for the growth and development of certain biological organisms, to be specific, certain families of microalgae, fungi, lichens and mosses.
Having patented the idea, the team is investigating the best way to promote the accelerated growth of these types of organisms on the concrete. The goal of the research is to succeed in accelerating the natural colonisation process so that the surface acquires an attractive appearance in less than a year. A further aim is that the appearance of the façades constructed with the new material should evolve over time, showing changes of colour according to the time of year and the predominant families of organisms. On these kinds of buildings, other types of vegetation are prevented from appearing, lest their roots damage construction elements.
Three layers of material
In order to obtain the biological concrete, besides the pH, other parameters that influence the bioreceptivity of the material have been modified, such as porosity and surface roughness. The result obtained is a multilayer element in the form of a panel which, in addition to a structural layer, consists of three other layers: the first of these is a waterproofing layer situated on top of the structural layer, protecting the latter from possible damage caused by water seeping through. The next layer is the biological layer, which supports colonisation and allows water to accumulate inside it. It acts as an internal microstructure, aiding retention and expelling moisture; since it has the capacity to capture and store rainwater, this layer facilitates the development of biological organisms. The final layer is a discontinuous coating layer with a reverse waterproofing function. This layer permits the entry of rainwater and prevents it from escaping; in this way, the outflow of water is redirected to where it is aimed to obtain biological growth.
CO2 reduction
The new material, which has various applications, offers environmental, thermal and aesthetic advantages, according to the research team led by Antonio Aguado and supported by Ignacio Segura and Sandra Manso. From an environmental perspective, the new concrete absorbs and therefore reduces atmospheric CO2, thanks to its biological coating.
At the same time, it has the capacity to capture solar radiation, making it possible to regulate thermal conductivity inside the buildings depending on the temperature reached. The biological concrete acts not only as an insulating material and a thermal regulator, but also as an ornamental alternative, since it can be used to decorate the façade of buildings or the surface of constructions with different finishes and shades of colour; it has been designed for the colonisation of certain areas with a variety of colours, without the need to cover an entire surface. The idea is to create a patina in the form of a biological covering or a “living” painting. There are also possibilities for its use in garden areas as a decorative element and as a sustainable means of blending buildings and constructions into the landscape.
Architectural renovation
The material lends itself to a new concept of vertical garden, not only for newly built constructions, but also for the renovation of existing buildings. Unlike the current vegetated façade and vertical garden systems, the new material supports biological growth on its own surface; therefore, complex supporting structures are not required, and it is possible to choose the area of the façade to which the biological growth is to be applied.
Vegetated façades and vertical gardens depend on a plant substrate in some type of container, or they use cultures that are totally substrate-independent, such as hydroponic cultures. However, they require complex systems attached to the construction itself (layers of material) and even adjacent structures made of metal or plastic. This can lead to complications associated with additional loads, the reduction of light, or the reduction of space around the building. With the new “green” concrete, the organisms can grow directly on the multi-layered material.
Patent and commercialisation
The research has led to a doctoral thesis, which Sandra Manso is writing. At present, the experimental campaign corresponding to the phase of biological growth is being conducted, and this will be completed at the UPC and the University of Ghent (Belgium). This research has received support from Antonio Gómez Bolea, a lecturer in the Faculty of Biology at the University of Barcelona, who has made contributions in the field of biological growth on construction materials. At present, a patent is in the process of being obtained for this innovative product, and the Catalan company ESCOFET 1886 S.A., a manufacturer of concrete panels for architectural and urban furniture purposes, has already shown an interest in commercialising the material.
