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Pioneering Vegetated Architecture in Colombia:
From Research to Regulations
By Andrés Ibáñez Gutiérrez
Faculty of Architecture, The University of Hong Kong and Biotectonica S.A.S., Colombia
All Photos and Graphics Courtesy of Andrés Ibáñez Gutiérrez
The recent development of vegetated infrastructure in Colombia is a unique case from the perspective of a developing country. In the last years we have had the challenge to catch up with and advance the latest experiences worldwide, but mainly face all sort of local challenges to bring out the democratic side of greening. We keep working to achieve that by doing more with less and by targeting quality via creative use of the resources available, reusing, adjusting and upcycling local materials.
Our process was all triggered by a research from the green building field that welcomed other disciplines. The best out of this approach was the technical prevailing over the romantic side. This is not the rule as it usually starts out in from the landscape or horticultural fields keeping certain distance with the buildings. This architectural approach of biotectonics had the aim of achieving feasible long lasting interfaces between the living plants and the inert engineering systems of the buildings in Bogotá, or simply test constructing with living material which demands knowledge on how it behaves just like knowing concrete, wood or other building material.
We then disseminated the results of the research in the public sector and educated the general public on how desirable and possible vegetated infrastructure was in Bogotá. The emerging green building market inertia and the echo from several public entities helped us to complete the loop we have today: A growing body of contractors, more than 50.000 m2 of green infrastructure projects installed or on-going, a national association, a database, and the official green roof guidelines of the city of Bogotá that will soon be released.
Today, we continue to work on the development of eco-productive architecture in Colombia from our research-based company Biotectonica, and in America, Asia and Europe from my doctoral studies in the University of Hong Kong. I investigate how the next generation of green buildings would incorporate a wide range of eco-productive technologies such biotectonics, photovoltaics and environmentally responsive materials to improve the environmental quality in urban areas by purifying air, managing water, absorbing noise, regulating climate, creating habitat for biodiversity, producing food or surplus energy from the sun among many other eco-services.
The paper is an overview of how this approach started in Bogotá three years ago. I hope many of the lessons left behind can be as useful for other latitudes as they have been for us.
|Green roof with a view in Bogotá. |
The practice of vegetated architecture in Colombia is in the process of being consolidated as a feasible technological choice. This paper explains the local process of green roofs dissemination initiated with a research project at National University of Colombia and accounts for the state-of-the-art both in public and private sectors.
Six topics are addressed: 1) the stage of transferring scientific knowledge from a research-based approach to the practice; 2) determination of the key local urban problems and technical parameters for experimentation regarding substrate, draining systems, vegetation and whole systems; 3) mechanisms of university-market-government engagement to overcome cultural and disciplinary barriers; 4) criteria for the future Bogotá green roof guidelines under development; 5) appropriate technological strategies for green roofs in response to the local challenges.
Issues of creativity, integration and quality are addressed in order to encourage a democratic practice of green applicable to low-cost projects. Some local strategies are described in which an integrative approach was followed to provide solutions to multiple design problems. Finally, at this point in time, Colombia is facing new challenges for the promotion of a high-quality and responsible long-term application of green roofs in the future. These challenges are described.
From research to practice
Research at National University of Colombia. Master in Building.
Green roof studies and diffusion in Colombia started four years ago under a research project for Master of Construction at National University of Colombia to be applied initially in Bogotá¹. The aim of the research was to identify urban environmental and social problems which could be treated with green roof systems, and evaluate the feasibility of applying this technology in a realistic way, facing technical, economical and cultural barriers in the local context. Before the research project, very few isolated empirical vegetated roofs had been implemented in Colombia, however, systematic research and technological development had not been previously conducted. Therefore, the potential for replicating green roof technology at the urban scale was limited.
In Colombian urban areas, vegetation of roofs had mainly been limited to street-level gardens covering underground parking zones. The construction of these gardens was driven by aesthetic or concerns and lack technological advance: These systems consist of virtually placing a ground garden on top of a concrete slab covered with an asphalt-based waterproof layer. The components were a gravel bed, geotextile and a regular organic growing media.
As a result, these few cases of empirical green roofs were heavy, required intensive maintenance and irrigation, and had water-related problems on vegetation and buildings. In rural areas, exceptional examples had been built empirically and motivated by personal curiosity of some individuals. They also consisted of local ground soil and vegetation on top of sloped roofs, without major additional technical considerations and awareness of the interaction among different components of the system. No evidence of modern extensive green roof examples was found in Colombia, neither evidences of systematic inquiry on the technical issues related to these systems prior the research addressed hereinafter
Environmental challenges in Bogotá
Bogotá is the biggest city in Colombia and is classified as one of the world megacities, having between 8 and 10 million inhabitants by 2015². Urbanization in Bogotá has created pressure on local landscapes and ecosystems. This has affected the quality of human living environments in turn. The research at National University identified the key local environmental problems of urban areas vis-à-vis hard surface construction: the heat island effect and alteration of local weather patterns, excess of runoff water, air and water pollution, destruction of natural habitat, excess of construction material waste, noise, and lack of green areas. Green roofs were seen as a possible moderating solution for these issues.
Heat island effect. In Bogotá, 67% of urban land is occupied by buildings in addition to different kinds of ground paving. Replacement of the natural soil and vegetation with impervious surfaces has originated two critical urban heat island areas: One in the historic downtown and the other in the south area of Bosa. This information has been validated by Pabon’s study (1998), which examined the spatial distribution of average temperatures in 10 weather observatories in Bogota from 1960 to 1989. According to Pabon’s data³, the temperature in Bogota rises 0.2 Celsius degrees per decade, above temperature in the natural surroundings of the local savannah. It is estimated that by 2050, the average temperature in Bogotá will be 2 to 3 degrees higher than the present⁴. In the last 5 years, the effects of this temperature on the local weather patterns have been evidenced recently by strong unexpected wind and ice events.
Storm water runoff. Raise on the air temperature is correlated to the increase of storm water volume, having a 3% tendency to increase per decade as shown by Pabón. As a result of this increase, several areas are at risk of flood, especially in the south urban areas. Recently, the local water infrastructure entity EAAB⁵ has invested nearly 2 billion Colombian pesos (USD$ 1.1 billion) in infrastructure to prevent over-load of the water evacuation system of the city. A key achievement was the construction of the dam, Cantarrana, to prevent overflows of the Tunjuelito River. The floods in the past affected more than half million people yearly. During the peak periods, dam Cantarrana has been registered to hold 222 thousand cubic meters of water. In spite of this recent compelling progress, several inundations have been registered in the central, southern and western areas. They have been caused mainly by obstruction of water inlet points. Bogotá district still has to face future challenges in this infrastructure while the urbanization continues to spread out.
Air pollution. Bogotá has the third place of polluted cities in Latin America due to the concentration of particles in the urban air (PM10). According to Secretary of Environment, the average of PM10 in the city is 130μg/m3. However, 70μg/m3 is the limit recommended by national standards, and 50μg/m3 by international standards⁶. The Secretary of Health estimates an expense of 1.5 billion Colombian pesos to attend to respiratory illnesses caused by the poor quality of the urban air. More than 19.45 tons of soot are released per day in the city. The sources are mainly industries operating with coal (13 tons) and vehicles (6.45 tons). The main affected areas are located in the southern and western areas of Bogotá. As a result, according to Institute of Environmental studies of National University, citizens only breathe acceptable air 16 days a year.
Noise. National noise standards establish a daily limit of 65 dB for residential areas and 75 dB for commercial and industrial areas⁷. However, in central areas of the city the daily noise levels go up to 85 dB. Areas in the surroundings of the airport have registered high levels emitted by 12.8% of the aircraft operations exceeding the range allowed. The Secretary of Environment has identified 5 critical areas affected by noise: Engativá, Fontibón, Santafé, Kennedy and Puente Aranda.
Construction waste. Excess of construction waste is another public challenge. The Secretary of Environment has established that 473 tons are discarded in public spaces, in spite of the prohibition by law. Even though there are regulations to ban it, and several disposal sites available for this purpose, the main landfill of Dona Juana has received approximately 200,000 tons of debris per year. In 2008, 120 critical points receiving debris illegally were identified.
Deficit of green areas. In Bogotá there are 0.15 trees per capita. Comparing with other densely built cities of Latin America, this rate is very low⁸. International standards establish 0.33 as desirable. The rate of green areas per capita recommended by United Nations for developing cities is 10 m2. In spite of the progress achieved in recent years by the local urban planning regulations POT⁹, in Bogota there are only 4.12 m2 of green areas per inhabitant. Southern areas in the city present the lowest ratios.
Destruction of natural habitat. In accordance to the map of habitat availability for the wild fauna in Bogotá (Secretary of Environment, 2008) more than 90% of the urbanized areas have null or very limited potential for biodiversity. Destruction of ecosystems linked to flora and wetlands have placed 28 species of wild birds on the list of conservation priority.
Pioneer research in Colombia
In spite of the multiple environmental problems that could be treated by implementing green roof technologies, prior to our research, green roof technologies were almost totally unknown in Colombia including Bogotá. The main causes of this lack of knowledge were 1) an absence of previous local research on green roofs, 2) lack of integration between different disciplines (architecture, construction, civil engineering, landscape, horticulture, ecology, entrepreneurship and industry-related disciplines), 3) lack of integration between academia, government and market, 4) cultural misconceptions linked to technical ignorance, 5) absence of incentives, 6) absence of technical expertise (no local companies) and 7) absence of successful examples.
The research project at National University aimed to overcome these barriers by validating local green roof technologies, taking into account local conditions including weather, materials, vegetation, economic limitations and the existing regulatory framework.
For the research 30 1:1 scale extensive green roof prototypes were constructed and evaluated following key technical parameters applicable in the local context and applicable FLL guidelines. Prototypes consisted on 50cm x 50cm modules with substrate depths varying between 3 and 8 cm. Modules were placed on a terrace in the south of Bogotá and their evolution was followed up under the local environmental conditions. Measurements were conducted to the materials aside, the complete systems and the weather conditions for one year. Twenty-five plant species were tested.
A measurement plan determined the variables to be tested, the equipment to be used, indicators, units, nature, quantity and frequency of tests. The plan also described detailed procedures for conducting tests. A technical sheet with description of each piece of equipment used was included as a record. On-site substrate measurements were compared with lab tests by Instituto Geografico Agustin Codazzi.
|Figure 1. Experimental modules|
A key challenge for massive implementation of green roof systems in Bogotá was to find ways of achieving low-cost systems while maintaining good quality and performance. Incorporation of local materials, industries and labor was crucial for future success. Components of prototypes were constructed considering these locally available resources.
|Figure 2. Determination of electrical conductivity of the proposed substrate|
|Figure 3. Determination of pH of the local substrate materials evaluated|
|Figure 4. Determination of particle size distribution of the local substrate materials employed|
|Figure 5. Determination of the thermal isolation provided|
Criteria for overall green roof systems tested
In response to environmental urban problems identified in Bogotá, the following key criteria were targeted:
Minimizing weight was one of the most important factors in the technological development of green roof systems, as most of the existing local roofs were not designed to support elevated loads. This is particularly critical in retrofitting cases. Components that mostly contribute to weight are substrate and drainage system. Traditionally, local gardens covering underground parking areas include heavy gravel as a drainage system and locally-available soil, which is significantly heavy.
For the prototypes studied, alternative materials and components were used as drainage: plastic 3D drainage systems made of local HDPE recycled and granular materials like industrial slag and granular expanded polystyrene. In addition, alternative low-cost materials and components such low-cost panel roofs and pipes were considered among other local construction elements commercially available. For experimentation on substrate, alternative materials locally available were tested: industrial slag, pumice rock, vermiculite, coconut fiber, rice husk, crushed brick and LECA¹º.
Affordability is a key factor for motivating massive application of green roofs in Bogotá. The research aimed to find mechanisms to reduce costs. Two strategies were addressed for the selection of used materials: reuse of waste material and adaptation of conventional roof panels.
Use of recycled, reused and waste materials
An environmental benefit of green roof systems is the chance of using recycled, reused or waste materials as components. In Bogotá, this alleviates the local problem of construction waste disposed in landfills and public spaces in the city. In addition, the environmental pollution and energy consumption needed to manufacture new materials is also reduced. The prototypes for experimentation included recycled, reused and waste materials in the drainage systems and the substrate.
Use of local materials
Local materials available within a 20 km ratio were used except coconut fiber and pumice rock, which were considered for their lightness even though their sources were Antioquia and Meta departments. The environmental impact of transporting these materials to Bogotá may be compensated with the low-density advantage. They can be considered local materials for green roofs in other regions of Colombia.
In addition to the abovementioned features, four other features were targeted and tested in response to the local problems of water runoff, noise, energy consumption and reduced life span of roofs: water retention capacity, reduction of water flow rate, acoustic isolation and thermal isolation, respectively.
Criteria for substrates tested
The following properties were measured for each substrate material and mix used in the prototypes: weight in dry state, weight under saturation, water retention capability, air volume, electrical conductivity, pH, granulometric distribution and content of organic matter.
Criteria for the vegetation tested
The aim was to test the resistance of plants to the local environmental conditions with no maintenance or irrigation. No previous research in Colombia had been done on vegetation for green roof systems prior to this experiment. For the research project, 5 sources of vegetation were identified and visited for plant collection: 1) a natural desert area near Bogotá, 2) several old traditional clay tile roofs home to spontaneous vegetation grow, 3) ground covers with xerophytic species 4) the xerophytic exhibition of the botanical garden in Bogotá, and 5) a collection of adapted CAM species from different regions. Twenty-five species were planted on the experimental modules and their response was examined during a period of 12 months. For further comparative tracking, a reference sample of each plant was kept in the original substrate. No irrigation other than the natural rain events was used. Additional properties of vegetation were observed: drought tolerance; survival and reproduction in low-organic-content substrates; survival and reproduction in shallow substrates; resistance to wind currents; low development in height; superficial root systems; ease of reproduction; and aesthetic potential.
Conclusions after research test cycle
All non-CAM species tested failed to survive during the dry season.
Five CAM species showed superior capacity of adaptation and reproduction under local environmental conditions and with no artificial irrigation. Planting by cuttings was shown to be successful in substrates with low organic matter content. Adaptation response included changes in color and volume of biomass. Two species showed yellow and white flowers respectively during May, June and July.
Local moss was partially decayed during dry seasons but was able to recover upon further rainy periods. Grass presented decay and no further recuperation. Four species of weeds were identified in experimentation modules. All weeds showed taproots.
Wind speed readings over 7.5 m/sec were registered in June, August and October. As wind might affect rooting, planting on exposed substrate is not likely to be successful during these months. Protection strategies like mulch and mats should be considered to prevent erosion of substrate and removal of cuttings or seeds. Particular microclimate circumstances should be considered for each case. The highest heat index readings were registered in January, February, March and September (above 30 degrees Celsius). During these periods, it is therefore advisable to consider backup irrigation depending on specific microclimate needs. Minimum wind chill readings below 5 degrees Celsius were registered during May, June and August. Wind barriers are advisable to prevent decay of the vegetation during these periods.
pH. Due to the high variability of pH value sand (variation of 6.05) coming from different sources, special attention and control on pH determination must be given for each case. In spite of the fact that LECA and pumice rock sources are not available within a 20 km ratio, these two materials should be considered as options to make substrates lighter. In addition, high pH values (above 8) may counteract acid rain registered in Bogotá and other acid components in the substrates. Although industrial slag is a waste material that can provide mineral nutrients at low cost, it is advisable to combine it with materials having high pH values due to its acidity.
Electrical conductivity of substrate materials showed variable values. In spite of their high nutrient content, lightness and low cost, coconut fiber, vermiculite and LECA present high values of electrical conductivity. Therefore, it is not advisable to use these materials in elevated proportions in substrates unless additional strategies are considered to balance conductivity levels.
Rice husks, coconut fiber and vermiculite were proven to store more than the equivalent to their own weight in water. These materials are advisable in regions having low precipitation. However, attention should be placed to the fact that weight will vary significantly from dry to saturation state. This is especially critical when retrofitting existing buildings.
Light and low-cost extensive green roof systems using local materials are feasible in Bogotá.
Sustaining light green roof systems bellow 100 kg/m2 with no irrigation is possible in Bogotá.
The most critical areas of Bogotá that would benefit from a massive green roof intervention are Central, El Tunal, Bosa, Kennedy, Puente Aranda and Engativá.
Overcoming Barriers. From research to diffusion.
|Figure 6. Strategies for reducing barriers towards green roof implementation in Colombia|
The studies of the National University showed that in addition to experimental research, a key factor for successful implementation of green roofs in Colombia was education. During all stages of research, we found lack of knowledge and misconceptions about this sustainable practice was in public and private sectors, especially about extensive green roof systems. In response to this concern, this research project included a strategic diffusion plan to educate the key government entities and motivate further research in the academia.
For academia, I formulated the first local university course on green roof systems, and it was opened in the bachelor of Architecture at Universidad Piloto de Colombia in 2009. The course aimed to introduce extensive green roof technologies to the future professionals and integrate this knowledge with other subjects of design and construction of buildings. The course included theoretical and experimental components. Diffusion in academia also included the publication of an article in the local academic magazine for architecture, Alarife: “Extensive green roof systems: A sustainable practice to be discovered and researched in Colombia.” Several lectures were given to architects and staff of the School of Urbanism and Architecture of National University. Other lectures showing the results of the research were given at the emerging local Green Building Council, Universidad Javeriana, Universidad de los Andes and the National Society of Architects (SCA).
Education of the general public included several articles in the National University news paper and in the newspaper El Tiempo. Radio programs were conducted on the National University radio station discussing the application of green roofs in Colombia along with other sustainable building practices. The aim of these diffusion mechanisms was to educate potential users and non-expert public about the benefits of green roofs.
In the public sector, results of the research were presented in several lectures to staff of the Secretary of Environment of Bogotá, Secretary of Urban Planning, Bogota council, Secretary of Education and the Mayor’s Office. These public institutions are the key local entities having direct participation in the creation of green roofs regulations, incentives and other government strategies for future promotion. The results of efforts are now being seen in several local government initiatives to include green roof guidelines in the future code of sustainable buildings of Bogotá (currently under development), and the law agreement 418 signed by the Mayor in 2009 to promote the use of green roofs technologies in Bogotá as a local measure to adapt to climate change and its mitigation. The latest dictates of the new public buildings to incorporate green roofs; the participation of Botanical Garden and Secretary of Environment as consultants for horticulture issues; and the creation of a local data base of green roof projects.
Diffusion in the private sector was also a key concern. During the research, several developers and design architecture offices in Bogotá were interested in the technical knowledge on local application of green roofs. The findings of the research motivated national and international clients to implement extensive green roof systems in Bogotá. The former designs and specifications were done for one of the former LEED certified office buildings in Bogotá, one library in Los Andes University, house clubs and other office buildings.
In some cases, prototypes were placed and tested in the project locations and additional specific weather measurements were conducted. Up to date, findings of the research project have been presented to more than 40 local firms and more than 18 green roof projects have been developed including specification, design and installation. Publications in the architecture magazine, Axxis, and building newsletter, Amarillo, complemented diffusion in the market sector. The aim was to promote a good practice on green roofs among architects and builders and encourage awareness of the multidisciplinary approach specially during the design stages.
From dissemination to implementation in the local market
|Living architecture in the city|
In 2009, the research project was awarded during in the Da Vinci competition for technology based postgraduate research projects in Bogotá organized by the municipality. The government provided training on entrepre-neurship to the researcher, and several studies were conducted to determine the financial, productive and market feasibility of a local green roof company based on the research.
As a result, the first local research-based green roof company Biotectónica was created. Biotectónica has developed 18 green roofs projects in Bogotá and one project in Santander department. Projects include consultancy, specification, design, implementation and maintenance of green roofs.
|Residential green roof |
Biotectónica is a research-based company developing local strategies to encourage the correct practice and large-scale implementation of vegetated architecture in Colombia addressing local economical and technical challenges. Several ongoing projects include experimental testing on acoustic capabilities of green roofs as a noise mitigation strategy in areas next to Eldorado airport. Other issues that are being investigated include the use of recycled materials, low cost systems, irrigation technologies, vegetation and substrates. Biotectónica has developed its own drainage system manufactured locally and is developing living wall systems. Further progress on vegetation tracking considers using advance algorithm image analysis tools. Other current practices are described hereinafter under the heading “situating green roofs in Colombia.”
Future Bogotá Green Roof Guidelines
The Law Agreement 418 (2009) stated that a Green Roof manual be included in the future local sustainable code of Bogotá. The four key features of the guidelines are:
1) Unlike most of the green roof guidelines, Bogota’s is about the functions, properties and technical performance required to guaranty optimal functioning of any green roof in the city, regardless of the technology employed. It is not centered on the layers or components, as each technology is uses different kinds of components.
2) The Guidelines establishes minimum mandatory requirements applicable in all cases and for all technologies. But also includes general recommended practices applicable to most common multilayered green roof technologies to meet the required performance.
3) Requirements are established for 4 different scales of implementation:
a. The green roof system and its operation.
b. The specific adaptation of a given system to a particular roof and the functional compatibility between both.
c. The integrity of the whole building intervened.
d. The compatibility with urban ecological structure the building belongs to, according to the ecological zoning of the local urban planning regulations POT.
4) Technical requirements for 5 stages of the lifecycle of a green roof are addressed: 1) Specification and design, 2) preparation, 3) Installation, 4) Maintenance and 5) disassembly and final disposition.
5) The guidelines include advance performance practices of green roofs and related technologies that are not mandatory but offer additional benefits and in the future could lead to incentives and tax deductions.
Situating green roofs in Colombia. Local strategies.
|A relaxing respite|
Creativity and integration are key strategies to be fostered by the emerging market in order to encourage a democratic practice of green roofs in Colombia. A wide range of systems including low-cost alternatives should be considered and developed. Several criteria underlined in the research project are already being offered by the market in response to the local challenge of achieving green roof systems that are affordable and high-quality.
|Greening Bogotá with vegetative roofs|
Biotectonica has implemented some of these strategies: Recycled HDPE draining systems manufactured in Bogotá at relatively low cost compared with imported systems having similar performance; fruit and vegetable waste for making compost as organic component in the substrate; local roof panels and granular polystyrene as alternative roof barrier and draining systems; crushed brick waste for substrates and filters considering that brick is widely produced locally; rice husk and industrial slag substrate components. Other elements like PVC membranes, edging and irrigation systems are also produced locally.
|Figure 7. Extensive green roof system using local alternative materials|
The two key current challenges at this point of rapid diffusion are: 1) the regulation of the practice in order to guarantee the quality and expertise of the emerging local green roof companies. This will be done through the recently founded (April, 2011) national organization RECIVE (Red Colombiana de Infraestructura Vegetada), and 2) the development of a public policy framework including incentives and revision of urban regulations.
Although the Law Agreement 418 is an important step as the starting point for encouraging the practice, it is still too general and does not establish the specific measurable goals at the urban level in Bogotá. Quantitative targets set by government entities are closely related to the development of incentives.
Key future challenges for academia
The main challenges are the integration of natural science disciplines (horticulture, biology, ecology, forest engineering) into the further research, e.g. selection of native species; carbon dioxide sequestration and oxygen release; root penetration; localized research projects in problematic areas of Bogotá and other regions of Colombia; life-cycle cost studies; studies on impact of green roofs on the local ecosystems; and further development of low-cost technologies.
Key future challenges for government
The main challenges are the development of incentives such tax tribute compensation¹¹, direct subsides, credits, priority for construction approval, reduction of utilities expenses¹² and planning regulations benefits¹³. A key challenge is to adjust two sets of current regulations.
The first one is the urban planning regulations having a gap on the use of terraces. The second are the current laws in force establishing incentives for practices that improve natural environment; however, there green roofs are not considered as one of these practices¹⁴.
Key future challenges for market
|Creation of local green collar jobs|
The main challenges are to develop technologies with local materials capable of responding to local weather conditions; develop productive local chains for green roofs and living walls technologies in order to foster local economy; develop a wide range of systems and methodologies for design in order to offer unique solutions in response to specific cases; develop affordable quality systems; develop modular systems to facilitate installation; and offer a comprehensive service considering the 5 stages of a green roof lifecycle.
|The future is bright for green roofs in Colombia;|
Graphic by BIOTECTONICA
Frauke, K. 2008. Megacities as global risk areas. In Urban ecology. An international perspective on the interaction between humans and nature, 583-596. New York: Springler Verlag.
Ibánez, R.A. 2009. Techos vivos: Sistemas de techos extensivos como tecnología sostenible en Bogotá. Bogotá: Universidad Nacional de Colombia.
Luckett, K. 2009. Green Roof Construction and Maintenance. New York: McGraw-Hill.
Lui Shiu Ting, E. 2008. Life cycle assessment of green roof systems in Hong Kong. Hong Kong: The University of Hong Kong.
Pabón, D.J. 1998. Análisis preliminar de la isla de calor en la sabana de Bogotá. In Cuadernos de Geografia, vol VII, 87-93.
Philippi, P. 2006. How to get cost reduction in green roof construction. In Greening Rooftops for Sustainable Communities Conference, May 11. Boston, 10 pages.
FLL. 2002. Guideline for the planning, execution and upkeep of Green roof sites. Bonn: FLL
NRCA. 2007. The NRCA Green Roof Systems Manual. Rosemont, IL: National Roofing Constractors Association.
Secretaria de Medio Ambiente. 2007. Atlas ambiental de Bogota.
Weiler, S.K., and Scholz-Barth Katrin. 2009. Green roof systems: A guide to the planning, design, and construction of landscapes over structure. Hoboken, N.J.: John Wiley & Sons.
¹ Ibanez, 2009.
² Frauke, 2008.
³ Pabón, 1998.
⁴ Today, average temperature is between 13 and 14 Celsius degrees.
⁵ Empresa de Acueducto y Alcantarillado de Bogotá.
⁶ US EPA.
⁷ Resolución No. 627/06 MAVDT: se adopta la norma nacional de emisión de ruido y ruido ambiental (parámetros permisibles, procedimientos técnicos y metodológicos para la medición de ruido, presentación de informes, y otras disposiciones).
⁸ Chile: 10, Mexico D.F.: 3.5. Source: Periodico el Tiempo, Bogotá.
⁹ Plan de Ordenamiento Territorial.
¹º Light Expanded Clay Aggregate.
¹¹ Reducción de impuesto predial, reducción de impuesto a la renta, devolución del IVA.
¹² Empresa de acueducto y Alcantarillado de Bogotá.
¹³ Ampliación del índice de construcción.
¹⁴ Decreto 3172 de 2003 y 2532 de 2002. Resolución 0136 de febrero de 2004. Ley 373 de 1997 alusiva al uso eficiente del agua.
Andrés Ibáñez Gutiérrez
Senior Architect and Project Director
Andrés Ibáñez Gutiérrez has led more than 40 design-build projects for clients in Colombia and the United States and has worked as a green building consultant in Colombia and Hong Kong. He holds a Master in Building and is a doctoral candidate at the University of Hong Kong. As a researcher in Colombia, Hong Kong, and Germany, he has written several papers for scientific journals and has pioneered eco-productive architecture research. He has been a university teacher and T.A. at the National University of Colombia, University of Hong Kong and Universidad Piloto de Colombia. He is a member of the World Green Infrastructure Network and founded the Latin America Green Infrastructure Network and the Green Infrastructure Network of Colombia, RECIVE (Red Colombiana de Infraestructura Vegetada). He has been a speaker in seminars and conferences in the United States, México, Peru, Hong Kong, China and Colombia. He is currently project director of BIOTECTONICA and researcher on eco-productive architecture. He is coauthor of the green roof technical guidelines of the city of Bogota, Secretary of Environment, 2011.
Contact Andrés at: email@example.com.
Publisher's Note: Andrés Ibáñez Gutiérrez is a finalist in the 2011 Innovadores de America; read his extended biography here.
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