CHAPTER 2
REVIEW OF RELATED LITERATURE
Literature review will provide the research strategies to different aspects of housing provision—its importance and effectiveness. The following concerns are:
a. Coordination of environmental, economic, and social requirements
b. Issues on built environment; energy, transport, water and wastes are addresses in a coherent manner to avoid conflicts
c. Technology and Materials
d. Bio- climatic Architecture
e. Land Use for Settlement Areas
f. Case Study
f.1 Local
f.2 Foreign
f.3 Bioclimatic design
According to Sieverts (2003), the whole building design and procurement process is very complex and encompasses development and construction from the urban and regional scale down to that of the individual dwelling. The involvement of local communities in formulating a criteria against which development is judged, and in approval access can be fragmented at the present time and this means that single emotive issues can sometimes dominate to the exclusion of an overall understanding.
A. Coordination of environmental, economic and social requirements
A.1Environmental. The process of design, particularly in early schematic stages is by necessity transformed by and ecological focus. Working with environmental strategies is more than assembling parts, or the choosing of systems as if selecting from a menu. Like a great collage, it is important for the parts to blend. (Kwok & Grondzik, 2007)
According to Viljoen and Bohn (2001), the choice of building materials affects the environmental impact of a house. All building materials are processed in some way before they can be incorporated into a building. The processing may be minimal, as in the case of a traditional cottage constructed from materials found locally, or it may be extensive, as in the case of prefabricated construction. This processing of materials inevitably requires the use of energy and results in waste generation.
Oliver (2006) quoted, “I will endeavor to enlarge on these misgivings, but first we should ascertain what is meant by these words. For guidance I turn to those standard works the Oxford English Dictionary and Webster’s Dictionary. In these, we find that the verb ‘to environ’ means to ‘encircle’ or ‘surround’, and the ‘environment’ is that which surrounds an object or living thing: ‘whatever encompasses’. Biologically, it is ‘the aggregate of all external and internal (my emphasis) conditions, affecting the existence, growth, and welfare of organisms’. It can be argued that there is no entity that is ‘the environment’, but an infinite variety of environments for all physical phenomena. Similarly, we may discover that ‘behavior’, while meaning for some 500 years, ‘conduct or course of action towards or to others’ has also meant for nearly as long a time, the ‘handling, or disposition of anything’, such as the ‘manner or action of a machine, a chemical, substance, organ, organism, etc’.”
These gave an indication of the direction to which he would turn, as he argued that an understanding of behavior patterns is ‘essential to the understanding of built form’ and that ‘forms, once built, affect behavior and the way of life’. In his view the forms of vernacular buildings result from ‘the aims and desires of the unified group for an ideal environment’ and socio- cultural forces ‘become of prime importance in relating man’s way of life to the environment’. Whether the ‘ideal environment’ is indeed, an objective or, in many cultures, is even a concept, remains to be demonstrated.
A.2 Economic. Ensuring that the housing solutions of the informal settlers are sustainable is important. On the part of the re- settlers, sustainability means that their new homes must be affordable, income adequate is maintained, and access to essential services like transport, education and health care is adequate. For the government, sustainability means, to the extent possible, costs are recovered. The government has to get back its initial investment so that it can then make use of these resources to build more homes for other informal settlers.
The value of buildings depends on the nature of ownership. For example, a major government agency may construct buildings with a 50- year (or more) life, whereas a property developer may simply construct buildings for immediate leasing and short-term sales potential. Each of these building owners is pursuing different measures of value, and the task for green building marketers is to recognize this state of affairs and to tailor their approaches to different owners accordingly.
According to Yudelson (2006.), buildings also build up value by having lower operating costs. In a low interest rate climate, the multiplier of annual savings to get incremental increases in building value may be as high as 14 (cap rate of 7%), whereas in higher interest rate environments, it can shrink to 10 (cap rate of 10%). So, the same projected annual savings in energy and water costs, or benefits of productivity increases, might be worth 40% more in a low-interest-rate economy.
A.3 Social. Cities are predominantly shaped by thoughts, however uncoordinated. Landscapes, by contrast are shaped by elemental forces. In principle, warmth and plants drive upward, water and matter transport downward. Vegetated landscapes tend toward balance. Towns don’t. almost all manifest excessive dryness. Dryness is a soul quality—arid, harsh inflexible and dead. In urban projects, it is encouraged to mitigate this using trees and ground plant in buildings. (Day, 2003.)
“It’s a sad fact that many people live in places that they don’t feel connected to. They don’t feel their value confirmed by the places where they live and consequently don’t themselves value these places. Such places attract abuse – starting with litter, then progressing via graffiti to vandalism and worse. They silently abuse the people who live in and use them. These are places over which residents have no control – or at least perceive themselves powerless to do anything about. Lea View House in Hackney, London is one example. Prior to rehabilitation in the 1980s, 90% of the residents of this public sector housing estate wanted to leave. Following intensive architect–resident collaboration, this socially and physically deprived community was turned into a place with positive community spirit. Vandalism, thefts and muggings, formerly common, virtually disappeared; tenants’ health improved, communal areas were looked-after and dignity and respect re-established. People now wanted to move onto the estate.” (Day and Parnell, 2003). This is just one illustration of the way care flourishes once a community feels proprietary about a place. As well as improving physical environment, this encourages social bonding, crime reduction and shared responsibility. However ugly, polluted, environmentally abused, is a place, the relationship to it changes as soon as people free to alter it. And it changes profoundly once people start work on it. It becomes their place – something they value. Not only are they empowered to co-shape our own future, but what people value, think, feel and do counts. It is of significant consequence – and so, therefore, they themselves.
People’s response to housing resettlement is characterized by patterns of coping strategies evident in how they generally deal with the compound conditions of poverty. The uncertainties that the urban poor face force them to “improvise” in order to survive in a fast-changing world that is increasingly making their lives more difficult. Because of limited resources and the various conditions that shroud their capacity to take hold of their future, the urban poor come up with short-term, quick- fix solutions to each problem as it arises. These coping strategies become part of the people’s culture and turn into a stock of knowledge which supplies people with interpretations and guides of action as they confront opportunities and challenges in their lives.
B. Issues on built environment
B.1 Energy
According to Grondzik & Kwok (2007), consideration of on- site energy production should begin with a review of energy efficiency strategies. Every effort should first be made to reduce demand. Reducing demand reduces the size of an on- site generation system or permits a system of a given size to offset a greater percentage of building energy load.
Given an efficient building, on- site energy production can further reduce environmental impact. Selecting the best strategy for on- site generation will depend upon factors such as type and location of the project, regional and micro climates, utility, rates and possible tax and financial incentives for clean and/or renewable energy.
“Plug loads have little direct effect on the architectural design of a building—electrical wiring is easily coordinated and concealed. The energy demands resulting from plug loads, however, will affect building energy efficiency and consumption, the sizing of cooling systems, and the sizing of on- site power generation systems. The greater the plug loads, the larger the supporting electrical system must be.”, says Grondzik & Kwok (2007). The design of on- site power and passive and active cooling systems demands that the nature of plug loads be well estimated during schematic design.
B.2 Water
Access to good quality potable water is fundamental to human survival and therefore basic to any slum upgrading scheme. The human right to water has been recognised in various international standards, in particular the General Comment No. 15 on the Right to Water which states that: “The human right to water entitles everyone to sufficient, safe, acceptable, physically accessible and affordable water for personal and domestic uses.”
In many low-income settlements, water is both scarce and expensive. In some countries slum-dwellers pay up to 30 times more than middle class residents for their water. Moreover, inadequate sanitation is one of the main sources of water contamination in urban poor settlements, leading to diseases and millions of deaths each year. Providing adequate sanitation facilities is therefore equally fundamental to low-income settlement upgrading.
The location of water in relation to the surface of land is a determining factor in type of water supply, building location, surface drainage, vegetation, and so on (Serote, 2004). The quantity of water affects seasonal allocation, conservation techniques, waste water treatment, population and the like.
According to Metcalf and Eddy (2006), “…for many water reuse applications such as agricultural irrigation and industrial cooling water, effluent from secondary waste water treatment plants was historically of sufficient quality. However, as quality goals for these and other water reuse applications have increased, spurred by the adoption of water reuse regulations, additional treatment has become necessary. Meanwhile, as regulations for effluent disposal have become more stringent, additional treatment has become necessary even for plants not practicing reuse. Thus, were feasible, it is reasonable to consider designing a treatment system suitable for potential future water use applications” the technologies now used for water reclamation have evolved from operation and processes used for water and wastewater treatment. Even greater removals for measurable constituents are possible through recent technology advances.
B.3 Transport
For housing to be satisfactory it must be situated so as to allow access to employment opportunities, health care services, schools, childcare centers and other social facilities. It must also be located in an acceptable environment, not, as is often the case, in environmentally hazardous areas such as dump sites, steep slopes, or flood prone areas. Though low-income settlements usually lack public facilities, it has been recognized that strong social networks play an immensely important role in alleviating this de.cit as well as in creating employment opportunities. Slum upgrading, as opposed to relocation, should make sure that social networks are maintained and distances to the work place are kept reasonable.
A hierarchical pattern of movement characterizes key aspects of many people’s activities whether they be child care, shopping or visiting friends and relatives. It does not, at present, characterize the most common movement – the journey to work – and if more sustainable living patterns are to be developed the distances between work and home need to be reduced. Nevertheless any new housing development has to provide for a hierarchical pattern of travel – a large number of short journeys with frequency decreasing as distance increases. In the past this was done entirely through the road system – a network of primary, secondary and local distributor roads. In the layout of housing estates priority was given to cars with road widths and junctions easing and speeding their paths. The needs of pedestrians were little considered.
Few destinations could be easily reached on foot and those journeys inevitably meant following the road layout. This often meant a long diversion from the most direct route.
If car dependency is to be reduced then the priorities will need to be reversed. Greater use of public transport and more walking and cycling means planning for that from the start. In contextual analysis, alongside the location of community facilities, the transport infrastructure needs to be mapped out. The routes and destination of buses needs to be established. Bus stop and railway stations need to be identified. Priority then, needs to be given to direct and easy pedestrian and cycle routes, both to local destinations and to join the public transport network. This means pedestrian desire lines need to be identified and routes worked out which take people along them easily and safely. Pedestrians should not be forced to take major diversions to get around buildings or to cross major roads.
B.4 Wastes
All waste system elements should be looked upon as being stages in the movement, or flow, of materials from the mining stage, via processing, production and consumption stage towards final treatment and disposal. A waste management system is a combination of several stages in the management of the flow of materials within the city and the region. A waste management plan is part of an integrated materials management strategy, in which the city makes deliberate and normative decisions about how materials should flow. The waste elements then become specific tactics to deal with specific materials after they have been consumed.
According to Klundert & Anshutz (2001), “Hazardous waste should be a particular area of concern during assessments of waste management systems. Hazardous waste is waste that is potentially dangerous to living beings and/or the environment. Hazardous waste is produced by a variety of sources including households, large- and small-scale industries, healthcare establishments, commercial operations like vehicle servicing, airports and dry cleaning shops and agriculture (e.g. unused pesticides, herbicides).” It is necessary to know what type of hazardous waste is produced by which sources in what quantities in the community. There are also numerous small enterprises that store their hazardous waste with the ordinary household waste, so it is mixed collected and disposed.
Instead of copying high- tech waste collection systems from abroad, it is encouraged to: (1) Allow a mix of approaches and technologies to be included in a well planned overall collection system, which includes sufficient secondary collection and transfer points, adequate shortage space and drop off centers; (2) Enabling specifically allowing pluralistic approaches in laws, ordinances, and regulations, and encouraging pluralism in private sector contracts; (3) Selecting a combination of collection techniques that allow for optimum recovery of valuable materials by municipal and private collectors (Klundert and Anshutz, 2001).
C. Technology and Materials
The earth’s resources are usually defined as being ‘renewable’ or ‘non-renewable’. The renewable resources are those that can be renewed or harvested regularly, such as timber for construction or linseed for linseed oil. These resources are renewable as long as the right conditions for production are maintained. Thinning out of the ozone layer is an example of how conditions for the majority of renewable resources can be drastically changed. All renewable resources have photosynthesis in common. It has been estimated that man uses 40 per cent of the earth’s photosynthetic activity (Brown, 1990).
The use of materials reflects another facet of the passive attitude. It takes over three hundred times more commercial energy to produce a concrete block equal in volume to a sun dried adobe block. It is conceivable to create a structure of integral thermal storage mass with an adaptable transmittive/ insulative weather skin that will accept or reject and automatically store all externally indecent heat energy or internally generated energy.
According to Berge (2001), a building structure usually consists of the following parts:
• The foundation, which is the part of the building that transfers the weight of the building and other loads to the ground, usually below ground level. In swamps and other areas with no load-bearing capacity the load must be spread onto piles going down to a solid base.
• The wall structure, which carries the floor, roof and wind loads. The walls can be replaced by free-standing columns.
• The floor structure, which carries the weight of the people in the building and other loads such as furniture and machinery.
• The roof structure, which bears the weight of the roof covering and possible snow loads.
Structural materials have to fulfill many conditions. They are partly dependent upon the construction technique to be used, and their properties are defined in terms of bending strength, compressive strength, tensile strength and elasticity. These factors give an idea of the ability of the material to cope with different forces. How this happens depends upon the design and dimension of the structure.
Berge (2001). Climate regulating materials control the indoor climate, and are mainly orientated towards comfort. They can be subdivided into four groups:
• air-regulating
• moisture-regulating
• temperature-regulating
• noise-regulating.
Air- regulating materials. Wind-proofing a building takes place in two areas, topographical and other wind breaking effects in the surroundings, and a wind-proofing membrane forming part of the building’s outer skin.
Moisture- regulating materials. Moisture-regulating materials are primarily used for waterproofing foundations, and as an inner vapor barrier to stop moisture from inside the building penetrating the wall and damaging it. They include materials that can regulate and stabilize air moisture in permanent absorption and emission cycles.
Temperature- regulating materials. Temperature-regulating materials mainly include thermal insulation materials built into the outside surface, but also materials that stabilize temperature relationships through their warmth-regulating properties. Subgroups for internal use are surface materials that can reflect, absorb or carry heat radiation through their structure and color.
Noise- regulating materials. Noise regulation is necessary to reduce and transfer sound of different qualities in and between rooms, and to guarantee a good acoustic climate. External sources of noise, such as road and air transport, necessitate good insulation in both walls and roof. Noise-regulating properties are dependent upon the material used, its design, placement and size.
D. Bio- climatic Architecture
Bioclimatic buildings are characterized by the use of building elements including walls, windows, roofs and floors to collect, store and distribute solar thermal energy and prevent overheating. Heat flows occur primarily by the natural mechanisms of convection, conduction and radiation rather than through the use of pumps ad fans. The objective is to manage energy flows and thus provide comfortable conditions in the occupied parts of the building at all times of the year and day. The definition also includes natural cooling and shading. The building is cooled by rejecting unwanted heat to ambient eat sinks (air, sky, earth and water) by means of natural modes of heat transfer. But the cooling load is firstly minimized through architectural design by reducing solar gains to the building fabric or through its widows, and by reducing internal gains. Thirdly, the use of radiant energy for daylighting while maintaining standards of visual comfort is also encompasses within the bioclimatic approach.
Daylighting must be the earliest and most natural ‘bioclimatic’ application, yet this is an approach in which there is renewed interest as energy issues in non-domestic buildings are studied. Architectural devices designed to increase the penetration of natural light deep into the interiors of commercial buildings and schools improve the distribution by techniques such as clerestory lighting, light shelves and so on, offer significant design potential. Cooling is of particular (though not exclusive) relevance in southern climates (Goulding and Lewis, 1997). Techniques include evaporative cooling and night ventilation, and substantial thermal inertia will usually form an important feature of such buildings. All climate-sensitive or bioclimatic architecture will incorporate solar protection and shading as appropriate to regional circumstances.
Integrated Design Principles
The main principle of bioclimatic design for passive and low energy buildings is to provide a comfortable environment by virtue of the passive features of design. A second principle is to use the active systems (mechanical equipment, such as air conditioning) with the passive systems to create an integrated solution for climate control. This can produce an integrated approach to design. One view of bioclimatic design is that the sphere of influence of architectural design lies in the use of passive design features, such as selecting the appropriate form and fabric of the building for climatic conditions. The aim is to achieve the indoor condition as close as possible to the comfort zone. Hence, through building form and fabric, varying outdoor conditions are controlled in order to achieve comfort. There are limits to the effect of passive systems; hence it is common to use active systems for times when comfort cannot be provided by passive systems.
Climate classification for bioclimatic design.
The classic texts of bioclimatic architecture consider a wide climatic and geographical coverage. They define representative climate types and zones with their meteorological features and present design recommendations for each case (Koenigsberger et al, 1975; Koenigberger et al, 1977; Konya, 1985; Lloyd Jones, 1998).
This traditional approach resulted in a classification of three basic tropical climates: warm humid, hot-dry and monsoon or transitional, with three sub-climates: upland, maritime desert, and tropical island.
In each case, the corresponding brief and design recommendations are defined, emphasizing the importance of controlling and modifying both the temperature range and average temperature, as shown below:
• Warm humid climates: These climates correspond to zones at low latitudes up to about 7° north and south of the equator, with high relative humidity, high average temperatures throughout the year, frequently cloudy skies, intense rainfall, abundant vegetation and low thermal swings, both daily and annually, with little seasonal variation.
Typical design recommendations include: solar protection, lightweight construction and cross ventilation. The limited annual and daily variation of temperature does not require control of the indoor temperature swing if the impact of direct sun and strong diffuse radiation from overcast skies is avoided, while the use of breeze can achieve a useful reduction in the apparent temperature, in spite of the low average wind velocities typically found in this equatorial region.
• Hot dry climates: Typical of desert zones, usually found between 15° and 30° north and south of the equator, with large daily and annual temperature swings and marked seasonal variations, predominantly clear skies, intense solar radiation, scarce rainfall and very limited vegetation. Typical design recommendations include: solar protection in summer, construction with substantial thermal inertia, controlled window sizes and protection from hot dry and dusty winds. The high external temperature variation, often exceeding 20° C, requires control measures to reduce the indoor variation. In summer, design strategies need to be implemented to reduce, or at least avoid, an increase in the average indoor temperature using selective night ventilation or evaporative cooling, while solar and internal gains should also be controlled. In winter, solar gains together with internal gains, can be used to increase the indoor average temperature.
• Monsoon or transition climates: These generally composite climates, found between the tropical and equatorial zones, have two clearly differentiated seasons, dry and rainy, according to the precipitation, though in India a cold season is also experienced.
The design guidelines for these climates combine the opposing requirements of the dry and humid seasons with difficulty. In many examples of the traditional and vernacular architecture, separate spaces with specific responses for the different seasons are found, with lightweight construction open to the breeze for the humid season and protected heavyweight construction for the dry season.
For the analysis of thermal performance of architectural project and the application of bioclimatic design principles, two distinct categories are defined (Evans, 2005):
Simple buildings: with limited internal thermal gains, rooms with natural lighting and ventilation and simple heating systems in cooler climates. In these buildings the average indoor temperature is similar or slightly above the average outdoor temperature for most months of the year, with the possibilities of solar radiation as a supplementary heating source. This category of building includes most schools and housing. Traditional texts on bioclimatic design have concentrated on these situations, where bioclimatic design resources to achieve natural conditioning can often provide a large degree or reduction in the need to heat and cool by artificial means.
Complex buildings: with large internal gains from occupants and equipment, as well as deep plan buildings where artificial ventilation and lighting is essential in the internal spaces. Large offices, hospitals and commercial centers are examples of this type of building. In this case the indoor temperatures may rise above average external temperatures, requiring artificial cooling in addition to artificial lighting and ventilation. In these complex buildings, bioclimatic design resources by themselves may be sufficient to avoid need for artificial conditioning, but are still important to reduce conventional energy demand.
Koegnigsberger et al (1970) inderline the difference between techniques to evaluate the behavior of a design after it has defined backward looking analysis and techniques to assist in the orientation of the design process forward looking analysis.
Table C.1 Project design stages, with the potential to integrate bioclimatic design resources and cost at each stage
| Design stage | Potential for applying bioclimatic approach and energy efficiency design resources | Cost of applying design resources |
| Program (building type, location, site | Very high potential | Potential alternatives at low cost |
| Preliminary sketch (initial concepts of forma and image) | High potential | Low cost (decisions on volume, orientation and form) |
| Sketch design (definition of architectural intentions) | Good potential | Low cost (decisions on volume, orientation and form) |
| Project (development in detail) | Limited potential to adjust bioclimatic characteristics | Increased cost |
| Details and specification | Very limited | Important cost of modifications |
| Construction | Very limited | Elevated cost of changes |
| Use | Extremely limited | Elevated cost of changes |
The possibilities of defining design guidelines based on climate conditions and comfort requirements, independently of the initial design concepts for specific projects, allows the definition of general guidelines for each climatic region.
Typological solution set for warm continental areas
The success in this climate of passively designed buildings (that is, buildings with no mechanical heating and cooling systems) depends upon a number of strategies that have to work together. They include proper orientation of the main rooms and windows, adequate size of the glazing, and the use of insulation, thermal mass and summer shading. As a general rule of thumb, whenever possible the longer side of the building should be oriented to the north. This will allow as much solar penetration as possible in winter, which is a requirement for passive heating. In summer, shading of the north-facing windows can be done with relative ease. West- and east-facing elevations should be kept to a minimum as the summer morning and afternoon sun can be quite intense. To minimize heat loss in winter, the roof and walls must be insulated and the use of double glazing is advisable. Thermal mass, such as uncovered concrete floors and internal brick walls, is required to help in moderating internal temperatures by averaging out the diurnal extremes. During summer days, this mass absorbs the heat, keeping the internal space cooler than outside. In winter, the mass stores the heat from either solar radiation or heaters, and releases it at night to help warm the internal space.
E. Settlement Areas
The primary concern in structuring residential patterns is the health and safety of the residents. This suggests that location of residential areas must be free from natural and man- made hazards to life and limb must have a pleasant and healthy environment. One simple way to ensure access is to declare by ordinance that all customary footpaths be recognized as public easements which must be kept at all times (Serote, 2004).
According to Serote (2004), “The ideal physical form that can address the above concerns effectively is the concept of “neighborhood unit”. An ideal neighborhood unit is a physical environment in which a mother knows that her child will have no traffic streets to cross on his way to school. An ideal neighborhood provides a safe environment and adequate facilities for children to play.” A cluster of a few neighborhoods may form a community to support higher level facilities and services like a secondary school, a district park or a feeder public market. These clusters are even conveniently linked to the town center.
Informal Settlements. An ongoing concern everywhere is how to deal with informal settlements. Informal settlements occupy their sites illegally. Unless their tenure is legalized on site, they must be relocated or resettled. Urban development through squatter eviction and relocation merely transfers the problem from the rejecting locality to the receiving community. The relocation sites are usually situated outside the built up areas, initially remote, isolated with minimum of infrastructure and services in place. Employment opportunities are not available on site and the relocatees have to commute to the inner cities to seek or keep their jobs. Commuting eats into a considerable portion of their day’s pay and so many of the relocatees sell off their lots and return to the inner cities o squat again.
The informal settlers must be relocated where they can have social networks and livelihood. The Urban Development Housing Authority (UDHA) directive to give priority to in- city relocation should be heeded to the extent possible. Where this is not possible and resettlement to new locations is the only option, the government should make sure that the relocatees continue to be integrated into the social and political life as well as linked to the markets in the host locality.
Topography. The factor topography is important in land use decisions because it affects the cost production, the cost of land development, the cost of laying networks and infrastructure, the cost of conveyance of water, drainage sewerage and the rate of erosion.
The individual characteristics of land are rarely considered in isolation in determining the use of a site or area. The bureau of soils uses nine capability classes (adapted from the US Dept. of Agriculture) denoted by letters A, B, C, D, L, M, N, X and Y. Limitations to such classes are shown as subscripts to the capability of class discussed on Table f.1.
| Class A | Very good agricultural lands with level to nearly level (0-3% slope) deep soil, well drained and with high natural fertility. This land class can be cultivated safely to clean-tilted or row crops with simple but good faming practices |
| Class B | Lands have slight limitations in use like drainage or excess water, soil and erosion problem due to slightly sloping relief from 3% to 8%. This land can be cultivated safely to clean tilted crops provided easily applied conservation practices like contour tillage and cover cropping are practiced |
| Class C | Lands are moderately good lands that should be cultivated with intensive conservation practices like contour tillage, terracing, cover, cropping, and the like on account of sloping to rolling relief of 8% to 18% slope. The limitations may be erosion, excess water, or soil condition |
| Class D | Lands are fairly good lands but require full management and complex conservation practices like teracing, contour tillage and cover cropping. This land is rolling, strongly rolling with 8% to 30% slope, is good for limited cultivation but is best suited to permanent tree crops |
| Class L | Lands are level to nearly level but too stony or too wet for cultivation. This land is limited to pasture forest use with careful management. |
| Class M | Lands are steep with slopes of 30%- 50%, maybe severely eroded or too shallow for cultivation. Class M lands are suitd only to pasture forest use with careful management |
| Class N | Lands are very steep with more than 50% slopes, too shallow, rough or dry for cultivation and are best suited forest use with careful management |
| Class X | Lands are wetlands that cannot be economically drained. These include mangrove swamps and marshes. Class X marshes are suited for fishponds or for recreational uses or are simply conserved for their aesthetic value |
| Class Y | Lands are very hilly, mountanious, barren and rugged. This class includes badlands, riverwash areas and sand dunes. Class Y lands should be reforested if trees are found to survive in these areas |
Table f.1
Among the nine capability classes, only Class A has practically no limitations. Therefore, class A lands have the capability to support all possible utilization types.[1]
E. Support Facilities
It is an essential concomitant of any housing development that its residents have easy access to a range of community facilities. These include open spaces and meeting places, education and health services, and shops providing goods and services. In many of the low-density developments of the past scant attention was given to such considerations. The provision of facilities was left to others – the local authority or the private market. The new approach to housing development recognizes the need to plan for communal facilities.
The companion guide to PPG3 – Better Places to Live – draws attention to the importance of ‘contextual analysis’:
“…greater emphasis now needs to be given to the linkage between new
housing and:
* local facilities and community infrastructure
*the public transport network
*established walking and cycling routes.
Making these linkages is fundamental to achieving more sustainable patterns of movement and reducing people’s reliance on the car.”
Contextual analysis of a development site identifies the location of existing facilities and networks. This helps to determine the suitability of the site for housing and indicates what types of housing might be most appropriate. It can identify a shortfall in facilities which might be made good within the development itself or provided nearby through the planning system. Finally, it can help to ensure that the site is planned in such a way as to link into local networks, providing good accessibility to nearby destinations and the wider community (Towers, 2005).
Table E.1 Provision for children’s play
| Age | Provision |
| 0 to 3 | Toys |
| 2 to 6 | Small scale equipment in local open space or communal design |
| 5 to 12 | Robust and complex equipment in small urban park or adventure playground |
| 8 up | Outdoor games in park specialist activity center/ theme parks |
Source: Introduction to Urban Housing Design: At home in the City, 2005 (p 63)
Examples of hierarchy of facilities which can be reached at different distances
| 5- minute walk | 10- minute walk | 20- minute walk, short journey | 40- minute walk journey |
| Communal garden | Local open space | Small Park | |
| Nursery, child minder | Primary school | Secondary school | Major park |
| Dentist | Hospital | Specialist hospital | |
| Daily needs | Weekly needs | Occasional needs | |
| Meeting room | Community center | Sports center | Sports club |
| Pub/ café | Restaurant | Cinema | Theater |
Source: Introduction to Urban Housing Design: At home in the City, 2005 (p63)
The pattern of the hierarchy depends partly on need and partly on the catchment population required to support a large-scale or specialized service. People need services such as a doctor’s surgery or a primary school near to their homes. At the other end of the scale, a further education college or a teaching hospital has to draw on a large area to justify its size and range of specialism. Table 3.2 gives examples of services which might be provided within a 5-, 10-, 20-minute walk or a short bus journey; and a 40-minute journey by car or public transport.
F. CASE STUDY
F.1 Local
NAVOTAS SANGAMANA HOUSING
Navotas is a municipality in Metro Manila. It is directly north of Manila, westvof Malabon City, and south of Obando, Bulacan. Navotas is part of the informal sub-region of Metro Manila called Camanava. Since Navotas is a first class municipality and highly urbanized the standard of living is high.
Navotas has the highest population density in Metro Manila with 220,000 people living in a 10.77 km2 strip of land, which is mainly made up of fishponds. Since the land is almost only fishponds 70% of the people live of fishing. There is natural gas power plant located in Navotas which provides the municipality with electricity. Natural disasters such as earthquakes and typhoons are common in the Philippines and especially near the Manila Bay torrential rains usually cause flooding and strong winds destroy houses. There are still some mangrove left along the bay and this has (so far) protected the residential area from storm surges. But it was also recently reported that an adjacent fault line has become active again and there is a risk of tsunami occurring if there is an earthquake.
A regulation regarding the construction of toilets is that the toilets have to have walls and floor of material that can resist water and damp. Presently they have already started to fill up the area with silt dredged from the river. The inhabitants of Sanagmana have decided to regulate garbage dumping; people are not allowed to throw anywhere other than in places reserved for garbage. Although they have this regulation the river is still very dirty because those living on the other side of the fishpond throw their garbage in the river. Every Friday the Local Government Unit, LGU, collects the garbage in Sanagmana.
HOUSING DESIGN CONSTRUCTION MATERIALS
The president of the community has already built a house based on the approved plan. It is the type of house that the organization regulates and that the rest of the families in the area should follow. However, there are many who already built their houses with a solid ground that is not allowed according to the building regulations.
Figure F.1.1 the house of the president
Figure F.1.2 Production of roof tiles Figure F.1.2 Production of roof tiles
At present, the people are using different kinds of materials for their houses such as: wood, sheet metal, concrete, bamboo, plywood, steel, sand, soil etc. They make their own roof tiles of cement, sand and gravel.
Bamboo is a very good material to build with, it is strong and when you build walls of bamboo the ventilation in the house is very comfortable. Even plywood can be made with the wood from bamboo. The president’s house is made of some of these materials.
The stilts are made of concrete, steel and wood from coco lumber. The coco lumber is the raw material of palm trees and it as strong as the bamboo and very cheap. The house construction itself is made of only coco lumber. The roof and house frame construction is specially made to resist earthquakes and strong winds.
Figure F.1.3 Roof Construction, Sangamana
The people are trying to work as much as they can with mature wood because it is stronger and better than the premature ones. The roof is made of tiles that they have made themselves; to reassure that the tiles would not fall off they are anchored with nylon to the roof beam.
Figure F.1.4 Tile anchored with nylon, Sangamana
Under the toilet, outdoors, is a septic tank especially for the faeces. The toilet, which has to be built with a material that can withstand water and damp, is made of Minerit. This material is a very sustainable material that is also resistant to termites. Minerit is often used as facade material in Sweden.
Figure F.1.5 Septic Tank, Sangamana
CONSTRUCTION
The soil condition in Navotas consists of twenty four meters of clay and silt which is not a good and stable material for foundation. For the type of house that was designed for Sanagmana (single detached lightweight house construction), the foundation used consists of individual footings and columns shaped like a T that needs to be buried approximately one meter below the surface or natural grade line. This would prevent damages during earthquake and seismic wave motions in the ground23. The units can also be joined in a straight line for row housing. The ground floor is located two to three meters above the ground to protect against flooding and allow strong winds to circulate.
The units usually have two floors, with the ground floor used as a living room as well as kitchen and study area, and the second floor as bedroom. The area under the house is commonly used for agriculture or as storage.
During typhoons the wind capacity is approximately 200 kph in Navotas. The wind swirls around the houses so it does not matter how one orients the roof, as long as it is well anchored to the unit and the unit is well anchored to the ground on stilts.
CHOICE OF MATERIALS
The choice of material depends on many conditions. It should be resistant to termites, rodents, humidity and corrosion. Besides it should be relatively cheap and easy to work with. As much as possible the materials, which usually are bought in bulks, should be found and produced in the Philippines.
The materials that are used in the construction are wood wool (omniboard), plywood, fiber cement-bonded boards (hardiflex), micro-concrete roof tiles
(MCR-tiles), posts made of concrete, and sometimes coco lumber instead of the expensive steel.
Woodwool/omniboard is resistant to fire and rodents. Hardiflex is also fire resistant. Both of the materials are used everywhere in the unit because of their termite and fire retarding qualities.
The MCR-tiles are made in Navotas by the inhabitants themselves using sand, gravel and water. The tiles are put in plastic moulds and then water cured and air dried for 28 days. These are then attached to the roof beams with nylon.
Mature coco lumber is commonly used as beams because it is much cheaper and locally available. Optional is steel which is more expensive, easily corrodes and needs special equipment and skills/expertise to construct. It also needs maintenance every five years to prevent corrosion.
DISCUSSION ON BUILDING MATERIALS
Omniboard. Omniboard is a material that can be used almost anywhere in the house as the name implies, Omni is a Latin word meaning everywhere. It is a wood wool board and uses a renewable fast-growing local wood species called Gemelina for wood wool fibres. Other fibre materials that may be used for Omniboard are bamboo, corn husks or rattan strips. These fibres are then bonded with Portland cement and pressed to the desired strength and density.
Figure F.1.6 House made out of Omniboard, Sangamana
The Omniboard is resistant to water and is a good insulation material. Tests have shown that the environment indoor temperature can be changed from 100°C to 35°C by using the Omniboard, which is good considering the hot and humid weather condition in the Philippines. It has also a good acoustical property.. Aside from being water resistant it is also durable to fire, termites and fungi.
It is easy to work with Omniboard. It can be sanded, nailed, screwed, drilled, riveted, plastered or topped with concrete and painted with water-based paints and it is best sawn with a circular saw.
CIB. Concrete Interlocking Blocks (CIB) are an alternative material to traditional Concrete Hollow Blocks (CHB) that are popular in the Philippines. These look like the toy LEGO. They have three holes for the reinforcement bars and special niches to accommodate electrical conduits. The bricks are made of cement, sand and water and are a very good material to build with in these climatic conditions. It is also a very good material for core constructions. Besides being easy to handle, it is also sustainable in many ways.
Figure F.1.7 Reinforcement installation
Bamboo. Bamboo is gigantic tree-like grass that grows in tropical countries like the Philippines. It has got an extremely hard exterior surface and grows ten feet per week. Bamboo’s flexibility makes it different from other wood materials and it needs special handling techniques because of this. But with the right knowledge one can build advanced and sustainable constructions such as; house constructions, scaffolds, etc. Because of its special properties, one cannot nail bamboo without pre-drilling and therefore it is usually plaited or tied together. Another negative property, which is negative, is the lack of durability to humidity and insects. But like wood, one can impregnate bamboo with substances like copper, chrome arsenic, etc. to strengthen it. This must be done when the bamboo is still green and before it has been dried. The status of the bamboo is not high because of its properties and is therefore often used as walls for storages, gable decorations and in similar constructions.
REFERENCE
Oloffson, Lina (2007). Sweden: Lund University
DISCUSSION
Sustainable Housing Development for the Urban Poor
The concept of “sustainable housing” does not only mean a durable construction; the concept is wider than that. A sustainable housing includes a functioning society where one can find necessities such as medical service, employment, food etc.
Successful projects from the past have factors contributed to success. The development given by the government is not enough. A housing facility does not stop to a house itself. It needs support facilities to make it livable.
The development of a housing facility needs a vivid study in each area; the land to be used, the accessibility, energy resources and water. Bioclimatic architecture shall be enforced in building a housing facility for the poor. The government need to a lot enough funds for the housing facility. Not only that the beneficiaries are Filipinos, but also they are the poor in the society—they need support in their basic needs, and of course, sustainability.
F.2 foreign
Ekurhuneli, Nigel
Figure F.2.1 Hostel
Approximately 112 informal settlements in Ekurhuleni exist, comprising approximately 135,000 informal units (shacks) in total. The current backlog (units without access to the four basic services) in the metro area is estimated at 170,000. These numbers do not take into account the growth in demand over the next 20 years.
Influx into the urban areas will continue into the future. Although all the informal settlements are provided with emergency water and are in the process of having sanitation facilities installed, they do not have permanent and adequate access to the four basic services:
Water;
Sanitation;
Electricity;
and Social services.
Most of these settlements are also situated on land not suitable for housing purposes and may even be dangerous, such as low-lying areas within the floodlines of rivers, land underlain by high-risk dolomitic formations, electricity and pipeline rights-of-way, and land undermined at shallow depths.
The availability of suitable land for housing close to the urban core areas is a problem and will necessitate rethinking housing typologies and densities. Although a large number of subsidy linked serviced stands (about 100,000) and houses (about 85,000) have been provided in Ekurhuleni during the last decade, the rate of housing delivery falls far short of the demand. The challenge is not only the number of houses to be provided, but equally the creation of sustainable human settlements and communities.
SETTLEMENT PATTERN
In terms of land use, Ekurhuleni comprises three main components:
*a central, east-west orientated mining and industrial activity belt which served as the core around which the nine towns were established;
*residential developments surrounding the above-mentioned activity belt; and
*rural and agricultural areas to the northeast and, in the central portion, to the south of the Metro.
Four major concentrations of historically disadvantaged communities exist in the area. All of these communities are situated on the outskirts of the main urban area and are in the areas furthest removed from where the bulk of job opportunities are situated. Together they accommodate approximately 65 percent of the total population of the metropolitan area.
The existing settlement pattern represents the typical apartheid planning structure, where the residential areas are situated on the periphery of the urban area, followed by a vacant buffer area, followed by industrial development that was intended to provide job opportunities, and which is then linked to the main economy via the rail and road networks. The mining belt was historically the core around which the various towns and settlements were established. The metro area has an evenly distributed, multimodal structure with no single, dominant node of activity.
Because of past mining activities, large parts of the mining belt are vacant. Numerous mining-related development constraints exist within this area, such as slimes dams and mine dumps, shallow undermining, dolomite, radon emissions, and so on.
REFERENCE
The cities alliance, 2008. Slum Upgrading Upclose.
DISCUSSIONS
The location of the said housing facility is near the urban area, the job opportunities for the beneficiaries has escalated. The housingis provided with the basic needs: water, electricity, social services and sanitation.
Although the plan has provided the basic needs, it is still not considered sustainable. This land as not suitable for housing purposes, as mentioned above, but rat her dangerous. The land is considered as a low lying area where there is a very high possibility of flooding. Housing should, therefore, be provided in the right locations, provide more choices in terms of typologies and tenure, give access to economic opportunities, furnish the necessary social amenities, and ultimately lead to improved quality of life.
F.3 Bioclimatic housing
| Christie Walk, Adelaide, South Australia | |
| Country | Australia |
| City | Adelaide, South Australia |
| Building Type | 3- storey attached house |
| Year of Construction | 2000-2002 |
| Project name | Christie Walk |
| Architect | Paul Downtown, Ecopolis Pty Ltd |
| Portrait | |
| The Christie Walk development is a mixed- density community housing project located in the heart of Adelaide CBD. The development is intended to be a pilot project demonstrating how communities can address the core issues for sustainable living in cities | |
| *water and energy | |
| *material reuse and recycling | |
| *healthy, people friendly public spaces | |
| The project features the onsite sewage and grey water treatment; on sit storage storm water; a solar hot system; power from photovoltaic; passive solar/ climate responsive design; use of recycled, non toxic materials with low embodied energy; pedestrian friendly spaces; local food production; a shared community garden and roof garden and reduced car dependency due to inner city context. | |
ECONOMIC CONTEXT
The project was initially funded by Wirranendi, whose members were drawn from the people who intended to live in the project. The non-profit structure of the development co-operative and building company played an essential role in keeping house prices within a range comparable to conventional inner-city properties in Adelaide. The buildings were mostly built with volunteer labour, which helped to reduce the start-up cost. House prices include all the community areas and facilities and range from Aus$120,000 to $350,000.
SITE DESCRIPTION
This development is located on the western side of the city of Adelaide. It is
only two blocks away from the Adelaide Central Market, minutes from the
main area of the CBD, and close to some of the parklands surrounding the
city. The project is located on a relatively small (approximately the size of two quarter-acre blocks) and awkward T-shaped site, which is severely constrained, with buildings on or close to most of the boundaries. This site, however, was selected by UEA since the project was meant to demonstrate to the general public that it is not always possible to have an ideal site for passive solar orientation (as found in many individual passive solar houses in the suburbs or in remote areas), yet it is still possible to achieve a healthy, comfortable and environmentally sustainable dwelling, while maintaining the occupant’s privacy, through careful and clever planning, design, use of building materials and landscaping.
BUILDING STRUCTURE
The townhouse building is located on the south part of the site and is elongated in an east–west direction. This location makes this building the only one in the site that has an ideal north orientation. Each unit has three floors; the ground floor consists of a small entry space, a sunspace, and an open living, dining and cooking space. There is a small courtyard at the back (south) side of each unit. The first and second floors consist of a north-facing balcony, a bedroom and a bathroom. Each level is connected by a spiral staircase, which also functions as a ‘thermal flue’ (see the section on (‘Ventilation system’).
The apartment block is located on the long part of the site, running on a north–south axis. This means that most of the openings are located on the east side of the building, and each unit has a very limited number of north facing windows (or none at all). Each unit is a single storey with one bedroom, a bathroom, a living–dining space, a kitchen and an open space that can be made into a second bedroom. The unit on the ground floor also has a small courtyard on the west side.
There are three detached straw bale cottages on the site: two with two storey and one with three storey. Due to its location on the site, each of these houses also has a limited number of north-facing windows.
BUILDING CONSTRUCTION
The external walls of the townhouse and apartment buildings are constructed of 300mm thick load-bearing autoclaved aerated concrete (thermalite). Between the townhouse units a 400mm thickness of load-bearing, lowstrength concrete (‘earthcrete’) is used for the internal mass. There is also some steel framing used in the apartment building. Load-bearing timber frames are used for the cottages and the external walls are made of rendered 500mm straw bales.
All of the buildings have reinforced concrete slabs on the ground floor.
The townhouse building use Pinus radiata proprietary trussed joists for the first and second floor construction, while the cottages’ upper floors use either plantation Pinus or recycled timber joists. A compressed straw panel (equivalent to particle board, but containing no woodchips or formaldehyde) is used for the floor decking of the apartment building and cottages.
Reinforced concrete slabs are used for the apartment building. All concrete in the slabs and mass walls contains the maximum percentage of fly-ash.
All window frames are made of recycled timber. All fixed windows are double glazed, whereas the operable windows are single glazed and are equipped with aluminums fly screens. Floor finishes are either Marmoleum, a modern variant of linoleum selected for its aesthetic merit and environmental credentials, or bamboo flooring. Locally produced ceramic tiles are used for all wet areas.
The roofs of the top floor of the apartment and the cottages are insulated with reflective foil and 200mm bulk (batt) insulation. The community roof garden also helps to cool the upper floor of the apartment building. Wall insulation of the townhouse and apartment buildings is provided by the 300mm thermalite walls, while the straw bales of the cottage walls also function as excellent thermal insulation.
All constructions, finishes and paints are non-toxic. Either plantation or recycled timber is used for all woodwork, such as doors and cabinets.
VENTILATION SYSTEM
All of the buildings/units employ comfort ventilation most of the time; nighttime ventilative cooling is used during summer. Vegetation surrounding the building filters and cools the outside air before it enters the building through small top-hung windows. These windows are set low on the wall to draw in cooler air. The outlets are high-level louvres, vents or ventable skylights. The latter are employed in the townhouse and cottage; the air is drawn to the skylights by convection through the stairwells. During hot summer days, all openings are closed, and external bamboo blinds are rolled down to shade the windows. The thermal mass helps to maintain the indoor temperature at a comfortable level. The small windows, vents or skylights are then opened at night to release warm air and bring in cooler outside air. This system helps to maintain the indoor temperature at a comfortable level.
ENERGY SUPPLY SYSTEM
The mains electricity for the whole development is drawn from the grid; however, photovoltaic panels will be installed on the pergolas of the roof garden on top of the apartment building. It is expected that the development will generate sufficient excess electricity to be sold to the local energy utility since the dwellings use very little energy for space heating and cooling, water heating and lighting, having been carefully designed to be as self-sufficient as possible.
During 2003, the energy consumption of some of the dwellings, occupied by one or two persons, was monitored in a separate project. The results show that the energy usage for the one-person dwellings in this development is reduced by 60 per cent of the state average for similar homes, and 50 per cent for the two-person dwellings. The average electricity use of the one person dwellings is 2293kWh per year and for the two-person dwellings is 3795kWh per year, compared with the state averages of 5469kWh per year and 7359kWh per year, respectively.
SOLAR ENERGY UTILIZATION
As described earlier, solar energy is used in active systems (solar water heating and, later, photovoltaic panels), as well as passively. Passive solar heating is avoided in summer and used in winter for all dwellings; however, due to the location and orientation of each dwelling, the amounts of winter solar gain are different. It is interesting to note, however, that although only the townhouse building has the ideal north-facing orientation, the winter performance of the other dwellings is not significantly different. This is because solar gain is still made possible through the openings, even though they do not face north, and also because of the high insulation value of the window glazing and walls. Figures 4.17 to 4.19 show the relationships between indoor and outdoor temperatures of the three dwellings during the winter of 2003.
In summer, direct solar gain is avoided through the use of external shades (bamboo blinds), balconies, pergolas and overhangs, as well as vegetation. During the day, the external shades are usually drawn and all openings are shut. Reflective foil (and bulk insulation) in the roofs of the apartment building and cottage also help to reduce solar gain.
BUILDING HEALTH AND WELL-BEING
Providing a healthy living environment is the main goal of this development.
Throughout the project, materials are selected very carefully. As described in the section on ‘Building construction’, only non-toxic construction and finishes are used and formaldehyde and PVC are avoided. All concrete used has a maximum content of fly-ash, a waste product of power stations, to reduce the amount of cement used. Cement production is one of the largest contributors of greenhouse gas emissions.
Noise control in each dwelling is provided by the massive walls and double-glazed windows, which also provide thermal advantages, as previously discussed. Air pollution is reduced due to the small number of cars within the site. Being located in the city, very close to good public transport, there is little need for car parks. The landscaping of the site is intended to create an interesting and productive community space. This includes the addition of vegetable and roof gardens, which also demonstrates that it is possible for a tight urban site to produce food. The paving of the site was done by the residents themselves, resulting in a creative and attractive outdoor environment.
WATER RECYCLING AND CONSERVATION
Storm water from the roof, balconies and other surfaces is collected in two 20,000 litre underground tanks. After filtering, this water is used for irrigation on the site and for toilet flushing. Grey water and black water are treated in a chlorine-free sewage treatment plant. It is planned that the composted solids will be taken to rural sites for use as fertilizer, while the filtered effluent will be returned to the site as a second-class water supply through the onsite storm water system. Most of the vegetation consists of native plants with lower water needs; some exotic plants are also used, where appropriate, as part of the passive design strategies.
PLANNING TOOLS APPLIED
No specific planning/design tools were applied during the design process.
The design was mainly done by the architect through the application of passive design principles for this climate. Thermal simulation was conducted by the author after the project was completed to analyse the effects of some of the building elements on the building performance. A calculation of the embodied energy of the construction was also performed after the project was completed.
The three dwellings described above were monitored by the University of
Adelaide from February 2003 to February 2004. A weather station was installed on the roof of the apartment building. The energy use (electricity and gas) of six dwellings was monitored by Urban Ecology Australia, led by Monica Oliphant from the University of South Australia. The occupants of the three dwellings were interviewed by the author and all of them expressed their satisfaction with the performance of their dwellings and of the whole development, in general.(Hyde, Richard. 2008. Bioclimatic Housing: Innovative designs for warm climates. UK: Cromwell Press.)
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