Sustainability of Social Housing in the Urban Tropics: A Holistic Development Process for Bamboo-Based Construction

This thesis is motivated by a tremendous need for more inclusive, sustainable and disaster resistant social housing in rapidly developing countries such as the Philippines. The 2030 Agenda for Sustainable Development and the New Urban Agenda name the use of local raw materials as one area for action. In the Philippines bamboo is an available, culturally rooted material, which is frequently used by rural and urban low-income groups. However, its current use in buildings does not meet the regulatory, technical and social requirements of urban spaces. The general objective of this thesis is to guide the development, implementation, and continuous assessment of a bamboo-based building technology for social housing in the Philippines, according to the multi-dimensional requirements of sustainability. The conceptual framework of the thesis is aligned to the standards EN 15643 and ISO 15392 on the sustainability assessment of buildings. A localization of the standards has been achieved through a multi-stakeholder participatory process. Beyond stakeholders from within the Philippines, this process builds on a learning exchange with Latin America, where significant knowledge on bamboo-based building exists, as well as Europe, where timber frame construction is established. Issue-focused research captured the performances in technical, environmental, social, economic and governance dimensions. It was shown that the most common bamboo species in the Philippines is of a structural grade that is suitable for low-rise house construction. With quality selected, treated bamboo culms and climate-adjusted house designs, the construction of reliable and durable buildings was possible, designed to withstand the impacts of their surrounding environment. The walls received a fire resistance rating of 60 minutes and full-scale test houses withstood the storm impacts of four typhoons with 120–213\ua0km/h wind speeds. A thorough life cycle assessment predicted that the building method results in a 74%-reduction in carbon emissions. Furthermore, surveys and physical measurements attested that a higher indoor thermal comfort is achieved. Active participation was applied throughout the research and implementation activities, and acceptance barriers were overcome among involved stakeholders. Beyond savings from a life cycle cost perspective of the buildings, the use of the renewable local material strengthened local economies and created rural-urban linkages.Sustainability theory was used as a tool for decision-making for the planning, implementation, and continuous improvement of 500 social houses across the Philippines. These were erected by the Base Foundation, an initiative supported by the Hilti Foundation, and its partners. In a continuous improvement process, the achievements and learning obtained in the research and implementation were exchanged in feedback loops over a period of 4 years. Sustainability is shown to be a continuous, balancing process that can be used to transparently discuss and evolve a holistic value proposition. Because adequate housing is only one of many components required for sustainable cities and resilient communities, this thesis aims to contribute to holistic integrated projects and policy advocacy

Innovation for Low-Rise Construction in the Urban Tropics: Utilization of Structural Bamboo for Cost-Efficient Housing

This paper deals with a cost-efficient construction technology using load bearing\ua0bamboo for urban low-rise housing in tropical Asia-Pacific. The potential of the technology\ua0to be applied at larger scale is discussed at the example of the Philippines as pilot country\ua0for its application. The assessment of alternative construction methods such as this one is\ua0motivated by a tremendous need for more affordable, sustainable and resilient housing\ua0around the globe. The urban poor, being the most underserved group in need of housing,\ua0often cannot afford conventional building technologies offered by the formal industry.\ua0Using locally available bamboo as structural component within the introduced standardized\ua0and quality controlled construction method is an entry point to provide performing and safe\ua0housing at lower cost. The paper highlights, however, that cost-efficiency and technical\ua0performance are not the only requirements for innovations to succeed on a market,\ua0especially due to the complex challenge of urban poor housing. Through learnings from the\ua0construction of 50 houses in the Philippines and interviews with various stakeholders along\ua0the value chain of the technology, barriers and opportunities for a scale-up are retrieved. For\ua0this paper, a conflated none-exhaustive overview of the identified aspects is documented. It\ua0was found that both barriers and opportunities directly linked to this technology are closely\ua0tied to a complex local value chain which ranges from upstream supply of raw material to\ua0downstream customer acceptance. The pilot application has shown further, that participatory\ua0product development reduces the acceptance barrier significantly by directly addressing the\ua0needs of low income customers. Material and skills availability, enabling policies and\ua0approval by legal entities as well as sustainability in supply of the organic raw material play\ua0important roles too. This complex set of interlinked aspects needs to be addressed according\ua0to targets in implementation-pace, and -scale as well as its intended social value creation.\ua0While multi-stakeholder participation is required for a successful up-scaling, a facilitating\ua0social enterprise, providing knowledge and services around the technology, can guide\ua0through the up-scaling

Sustainability of Social Housing in the Urban Tropics

The Licentiate thesis looks at sustainable building approaches for social housing in emerging economies. It combines theoretical concepts with practical applications of sustainability and underlines the relevance and strength of multi-dimensional development. At the example of the Philippines, the conceptual framework for a multi-perspective development process of a bamboo-based building system is developed. Sustainability Assessment Criteria are defined based on data from three stakeholder clusters: (1) Builders and users of traditional bamboo houses in the Philippines; (2) Stakeholders involved in using forest products for housing in countries around the world; and (3) Stakeholders in the field of social housing of the Philippines. Through a qualitative content analysis, research areas are identified and categorized into five dimensions of holistic sustainability: technology, society, ecology, economy, and governance. The Licentiate names methods leading to measurable, quantitative endpoints for those research areas and presents selected results: from mechanical property and fire resistance testing in the technical pillar, to environmental impact assessment in the ecological dimension as well as pathways towards a legal approval as contribution to the governance pillar. An accompanying implementation project is introduced, producing outputs in economic, social and governance dimension, and a pathway for the course of the PhD is shaped. By the end of the PhD thesis, a holistic sustainability assessment of the building technology will be provided for the given context of social housing in the Philippines

Sustainability of Social Housing in the Urban Tropics

The Licentiate thesis looks at sustainable building approaches for social housing in emerging economies. It combines theoretical concepts with practical applications of sustainability and underlines the relevance and strength of multi-dimensional development. At the example of the Philippines, the conceptual framework for a multi-perspective development process of a bamboo-based building system is developed. Sustainability Assessment Criteria are defined based on data from three stakeholder clusters: (1) Builders and users of traditional bamboo houses in the Philippines; (2) Stakeholders involved in using forest products for housing in countries around the world; and (3) Stakeholders in the field of social housing of the Philippines. Through a qualitative content analysis, research areas are identified and categorized into five dimensions of holistic sustainability: technology, society, ecology, economy, and governance. The Licentiate names methods leading to measurable, quantitative endpoints for those research areas and presents selected results: from mechanical property and fire resistance testing in the technical pillar, to environmental impact assessment in the ecological dimension as well as pathways towards a legal approval as contribution to the governance pillar. An accompanying implementation project is introduced, producing outputs in economic, social and governance dimension, and a pathway for the course of the PhD is shaped. By the end of the PhD thesis, a holistic sustainability assessment of the building technology will be provided for the given context of social housing in the Philippines

Fire resistance for low-rise housing in the tropics: Test results for bamboo-based construction systems

The use of round bamboo as load bearing member for low-rise housing is an interesting alternative construction method for tropical regions. Similar to timber engineering, a predictable fire resistance is a requirement for its legal approval and application at scale. The research presents fire test results on selected bamboo-based construction systems developed in Asia-Pacific and Latin America. Tests were conducted in Indonesia according to the National Standard SNI 1741, which is referring to ISO 834-1 and JIS A 1304. Different bamboo wall cross-sections were tested in specimens of 1050mm by 1050mm and evaluated according to insulation, integrity and mechanical resistance criteria. All specimens received a rating of 60 minutes resistance. The research provided a general understanding of the system response and highlighted critical variables of the wall system, which can be transformed into design recommendations

Environmental performance of social housing in emerging economies: life cycle assessment of conventional and alternative construction methods in the Philippines

Purpose The environmental impact of the social buildingstock is relevant, particularly in emerging economies. Life cycle thinking is not yet established, however. Locally available, alternative building concepts could potentially reduce the environmental impact of the construction segment. This paper examines the environmental performance of Bas-built low-cost housing for an example of the Philippines, and the potential to reduce its environmental impact through use of three alternative building technologies: cement–bamboo frames, soil–cement blocks, and coconut board-based housing.Methods Life cycle assessment models are implemented andevaluated with software SimaPro, using the single-impact indicators global warming potential (GWP) and cumulative energy demand (CED) and the multi-impact indicator Impact2002+. According to EN 15978, the life cycle phase product and construction process (A), use stage (B), end-of-life (C) and supplementary information beyond the building life cycle (D) have been assessed. Theoretically calculated inflows from standard construction procedures used in phase A have been verified with 3 years of empirical data from implemented construction projects. For phases B, C and D, attention was given to servicelife, use-phase, allocation of waste products, biogenic carbon and land-use assumptions. Scenarios reflect the actual situation in the emerging economy. Processes, such as heat recovery from thermal utilization, which are not existing nor near to implementation, were excluded.Results and discussion For an assessment of the phases A–B–C–D with GWP, a 35% reduction of environmental impact for soil–cement blocks, 74%for cement–bamboo frame, and 83% for coconut board-based houses is obtained relative to a concrete reference house. In absolute terms, this relates to a reduction of 4.4, 9.3, and 10.3 t CO2 equivalents over a service life of 25 years. CED showed higher impacts for the biogenic construction methods coconut board and cement–bamboo frames of +8.0 and +4.7%, while the soil–cement technology was evaluated −7.1% compared to GWP. Sixteen of 17 midpoint categories of Impact2002+ confirmed an overall reduction potential of the alternative building methods, with the midpoint category land occupation being the exception rating the conventional practice over the alternatives.Conclusions It is concluded that the alternative construction technologies have substantial potential to reduce the environmental burden caused by the social housing sector. The service life of the alternative technologies plays a vital role for it. LCA for emerging economies needs to incorporate realistic scenarios applicable at their current state or belonging to the most probable alternatives to ensure valuable results.Recommendations for further research are provided

Binderless boards made of milled coconut husk: an analysis of the technical feasibility and process restraints.

The possibility of producing binderless panels made of milled coconut husk, a largely available by-product of the coconut oil industry, has been shown in previous researches. Long pressing times and a high risk of blisters have however hindered the industrial implementation of the process. In this study, a more energy-efficient manufacturing process, involving a tailored degassing step, was developed on a laboratory scale and then validated at an industrial size (2 x 1 m(2)). To achieve mechanical properties close to the European and Japanese standards for fibreboards and to avoid the delamination of the boards, final densities between 900 and 1000 kg m(-3) had to be targeted. Similarly, a successful board production was only possible if the moisture content of the husk was between 10 and 25%. The need for a suitable mat-forming technology to avoid the risk of warping of the panel was highlighted

Determining material suitability for Low-Rise housing in the Philippines: Physical and mechanical properties of the bamboo species Bambusa blumeana

The use of cellulosic materials in the construction of low-rise housing in tropical climates has great potential. Bambusa blumeana (B. blumeana, J.A. and J.H. Schultes), the most abundantly available bamboo species in the Philippines, is a promising alternative material for the construction of cost-efficient buildings. However, to comply with municipal rules and regulations for construction, a comprehensive understanding of the organic raw material is needed to permit its application as a load-bearing structural member. In this study, the physical and mechanical properties of B. blumeana bamboo from a typical growth region of the Philippines were tested according to ISO 22157-1 (2004) and ISO 22157-2 (2004). The characteristic strength values of B. blumeana were as follows: compressive and tensile strengths parallel to the grain of 20 and 95 MPa, respectively; shear strength of 5 MPa, bending strength of 34.6 MPa, and the mean and fifth percentile modulus of elasticity of 13100 and 8600 MPa, respectively. Based on these results, a recommendation for permissible stresses for structural design was made in line with ISO 22156 (2004)

Indicator based sustainability assessment tool for affordable housing construction technologies

With the growing worldwide demand for affordable housing and the importance of supporting and stimulating sustainable development, the need for sustainable solutions in the affordable housing sector is at a peak. The present paper screened about 75 construction technologies and assessed 46 of them. The present paper presents the first results of a step wise approach to identify, assess and recommend most promising technologies for affordable housing projects. A database was developed to store detailed technical information about each of the technologies. A grading and ranking scheme was developed to identify the most promising construction technologies from a sustainability perspective. The main challenges for affordable housing production and most relevant assessment indicators were identified from the literature, interviews and meetings with experts. An indicator based assessment system was developed by cross-referencing the identified eight challenges with ten selected indicators. The final ranking demonstrated that a wide variety of technologies perform strongly overall, and these range from bio-based materials, such as bamboo and timber, to industrialized technologies, such as concrete. Moreover, the possibilities for improvement are vast, and the option of combining different technologies seems to be the most promising approach