An Introduction to Urban Housing Design

AT HOME IN THE CITY

Graham Towers

• Publisher: Routledge
• Year: 2013
• eBook ISBN: 9781136391842
• Edition: 1
• Topic: Architecture
• Subtopic: Architecture General

This clear and concise guide is the ideal introduction to contemporary housing design for students and professionals of architecture, urban design and planning. With the increasing commitment to sustainable design and with an ever-increasing demand for houses in urban areas, housing design has taken on a new and crucial role in urban planning. This guide introduces the reader to the key aspects of housing design, and outlines the discussion about form and planning of urban housing. Using chapter summaries and with many illustrations, it presents contemporary concerns such as energy efficient design and high density development in a clear and accessible way. It looks at practical design solutions to real urban problems and includes advice on reclamation and re-use of buildings. The guidance it presents is universally relevant. Part two of the book features current case studies that illustrate the best in high density, sustainable housing design providing the reader with design information, and design inspiration, for their own projects.

PART ONE

ISSUES IN URBAN HOUSING

1CONTEXT

THE ENVIRONMENTAL IMPERATIVE

SUMMARY

Two critical trends have combined to bring about a fundamental change in housing development policy in Britain at the beginning of the twenty-first century. One is the increasing evidence of climate change caused by the burning of fossil fuels to generate energy. This has resulted in an accumulation of ‘greenhouse’ gases causing a rise in world temperatures and changes in weather patterns. Widespread concern over climate change has resulted in agreed targets to reduce the production of carbon dioxide emissions. The other trend is the predicted growth in the number of households primarily caused by a large increase in the numbers of single people. This would require a further 3.8 million homes in the first 20 years of the new century.

These trends threatened to impose an unsustainable burden on scarce resources whether these were land, materials or traditional fuels. The new policy developed to address this threat meant concentrating new housing on previously developed ‘brownfield’ urban sites. It also meant that new housing needed to be denser in order to reduce both land take and the need for transport, particularly car use. To achieve these ends it was essential to identify land for this new housing in the existing urban areas. On the face of it, these were already fully developed, but subsequent studies have identified significant quantities of unused and under-used land and buildings ripe for renewal.

CLIMATE CHANGE

The opening years of the new century have been marked by dramatic weather patterns. In Britain and northern Europe there has been widespread flooding affecting many towns and cities. In 2002 two of Europe’s heritage cities – Prague and Dresden – were inundated and seriously damaged after the entire rainfall of a typical August fell in just 36 hours. At the same time parts of Africa were variously affected by floods and drought. In Australia, prolonged periods without rain resulted in serious bush fires. In 2003 there were record-breaking heat waves in Europe, Asia and north-east America. It seemed incontestable that the world’s climate was changing.

Many things can affect the climate including sunspot activity and volcanic eruptions. Cyclical changes take place over a long period. There have been repeated ‘ice ages’ and there is good evidence that many parts of the world were warmer a few hundred years ago than they are today. Nevertheless there is now a widespread consensus that the recent changes are due, at least in part, to the ‘greenhouse’ effect. Geological evidence showed that, over millions of years, the proportion of carbon dioxide in the atmosphere never exceeded 250 parts per million. By the end of the twentieth century, though, it had risen to 360 parts per million – an increase of 44 per cent caused by the use of fossil fuels to produce energy.

When hydrocarbons such as petrol, oil and natural gas are burned they produce carbon dioxide and water vapour. The carbon dioxide accumulates in the upper atmosphere, along with other gases such as methane. This layer of ‘greenhouse gases’ acts as an insulating blanket limiting the amount of heat which can escape from the earth and causing ‘global warming’. The actual rise in temperatures seems slight – between 1975 and 2000 mean global temperatures rose by little more than 0.4 degree centigrade. However, small rises can have dramatic effects. The last ice age was caused by a fall of only 5 degree centigrade, a rise of 2 degree centigrade would be enough to make the countries of the Mediterranean uninhabitable, while an increase of only 1 degree centigrade causes a rise in sea levels of up to 12 centimetres through the melting of permanent ice. The main effect of the small rise in temperature over recent years has been the increase in rainfall. This is because evaporation is increased by the warmer climate and, at the same time, the warmer air has the capacity to carry more moisture. Higher rainfall is predicted to continue, characterised by increasingly violent storms.

The Kyoto protocols

Concerns about global warming were first addressed internationally at the world conference held in Rio de Janeiro in 1992. There a generalised target was set to reduce carbon dioxide emissions to 1990 levels by the year 2000. This target was mainly aspirational and had little effect. The issue was tackled again at a follow-up conference in Kyoto in 1997. This time, through tough negotiations, binding targets were agreed. An overall aim was to reduce carbon dioxide emissions, based on 1990 levels, by 5.2 per cent over the period up to 2012. Within this, different targets were agreed for each country. All the participant countries left the summit committed to a specific level of reduction. All, that is, except the USA which is not only the world’s biggest economy it is also the biggest producer of carbon dioxide emissions.

The target set for Europe as a whole was 8 per cent but Britain had agreed to a higher target – a reduction of 12.5 per cent by the year 2012. Britain’s carbon dioxide emissions come from three main sources:

1 productive industry including power generation;

2 energy inefficiency in housing and industry;

3 transport, especially road vehicles.

To achieve the target, reductions must be made in all spheres. Some early progress was made in reducing emissions from power generation by the switch from coal to natural gas. Further reduction needs to be made by switching to more efficient methods of production such as combined heat and power (CHP) and by increasing power generation by renewable sources. These include wind power, tidal and wave power, solar energy and a number of other new technologies. In 2002 only 2 to 3 per cent of Britain’s electricity came from these sources but the aim is to increase this to 10 per cent by 2010 and 20 per cent by 2020.

In the UK, housing accounts for 27 per cent of carbon dioxide emissions. There is a need to reduce both the energy in constructing housing and the energy inefficiency in running homes. The prime target must be improvements in the efficiency of space heating which accounts for half the greenhouse gas produced from housing. Transport accounts for about 26 per cent of emissions. This includes public transport, which generally uses energy efficiently, and air transport which does not. Remarkably, no tax is levied on aeroplane fuel which is one reason for the relentless growth in air travel. However, the main problem is Britain’s 25 million cars. These are used more extensively than anywhere else in Europe and are the main source of greenhouse gas emissions from transport.

The need for equilibrium

In the long run the aim must be to reach a balance where energy consumption is in harmony with the capacity of the environment. One definition of sustainability is economic activity or development which meets the needs of the present without compromising the ability of future generations to meet their own needs. In terms of the greenhouse effect this means not triggering irreversible environmental change or pollution which damages the health or well-being of our descendants. This is a lofty aspiration and hard to achieve. It is generally considered that to achieve balance the reduction in greenhouse gas emissions is not the 5 per cent targeted at present but 60 per cent. Some consider that the environment is permanently damaged and that the best that can be achieved is to avoid making the situation worse.

While the greenhouse effect is the most pressing environmental issue of the moment it is not the only facet of the search for sustainability. A broader picture can be gained by considering the concept of ‘the ecological footprint’. One definition of the ecological footprint of a city is the land area required to provide it with food, supply it with timber products and re-absorb its carbon dioxide emissions by areas covered with growing vegetation. Defined in this way the ecological footprint of London is 125 times greater than its actual surface area. This amounts to 20 million hectares – almost the equivalent of the entire productive land area of Britain. But even this is not the full picture. It does not take account of the land required to produce building materials and manufactured goods or land required to dispose of waste products of all sorts. Adding this in would considerably increase the footprint area.

Ecological footprints can only be calculated on a regional basis, but once compiled they can be broken down to per capita figures. It has been calculated that the ecological footprint per person in India is 0.4 hectares while in the USA it is 5.1 hectares. In equity the citizens of India must be allowed the opportunity to improve their standard of living. But if everyone in the world were to live like the current inhabitants of the USA their ecological footprint would require at least two additional planets like the Earth. Bringing the world into balance requires a dramatic reduction in the ecological footprint of the developed world and sustainable development everywhere else. This does not just mean a reduction in greenhouse gas emissions but a general reduction in consumption and in the production of waste. In broad terms this means reducing the use of scarce resources. Aside from their effects on the atmosphere, fossil fuels are themselves a natural resource in limited supply. So are many minerals and natural products used in manufacturing and building. Demand for scarce resources can be limited by greater efficiency in their use but the recovery and recycling of waste products also plays a critical part.¹

POPULATION CHANGE

Another scarce resource, particularly in the highly developed parts of northern Europe, is land. The loss of land to housing in the south-east of England had been a concern for some time. Between 1945 and 1990 in the ‘home counties’ around London, 170 000 hectares were consumed by new development – an area of land bigger than London itself.² These concerns were exacerbated by government estimates of the late 1990s which suggested that over a period of 25 years, 3.8 million new homes would be needed to meet rising demand.

These new demands were prompted by changes in the English household structure with fewer families and increasing numbers of people living alone. It was estimated that 80 per cent of these new households would be single people. The biggest increase was among people in their 20s and 30s living on their own. There was also an increase in those divorced, or not in permanent relationships and a growing proportion of elderly people.³ These projections seemed to be confirmed by the 2001 census which showed that, for the first time, elderly people formed a larger proportion of the UK population than children – 21 per cent were aged over 60 years, while only 20 per cent were under 16 years of age.⁴

The Urban Task Force

Concern over these projections led the government to appoint an Urban Task Force led by architect Richard Rogers, to examine how the large quantity of new housing required could be accommodated. The initial assessment of the Task Force was daunting. Pointing to the low density of recent housing development they estimated that if all the new homes required were built at similar densities they would occupy a land area bigger than Greater London. Even if only 45 per cent were built on greenfield land at prevailing densities they would cover an area of countryside larger than Exmoor.

Faced with such enormous losses of open land and the difficulty of servicing such new development, the Task Force defined four key issues which had to be addressed:

1 The need for increased densities. Having established the large areas of countryside which would be taken by maintaining existing policies, the Task Force concluded that higher densities would be required in new development with more of it concentrated on recycled urban land. They cited research which showed that the most significant reductions in land used could be achieved by relatively modest increases in density. While modest increases would achieve considerable land saving, the report points out that relatively high densities have considerable advantages creating better local services and facilities, and easier access to them. It, therefore, suggests ‘pyramids of intensity’ – high-density development around urban foci of services, employment and transport.

2 The need to reduce car use. Given the high-energy consumption and the relentless growth in road traffic, there is a clear need to reduce the use of cars. Building at higher densities would reduce dependency on car travel, making better public transport possible. As densities increase so more frequent and efficient public transport systems become viable. With services and facilities closer to homes, far more journeys could be completed by walking or cycling. At the same time, concentrating more development on to urban land would reduce distances between work and home, and reduce transport needs. The report recommends higher investment in public transport and disincentives to car use including lower parking provision and higher charges.

3 The need to create high-quality environments. Before the industrial revolution Britain built cities of high quality. Bath, Edinburgh and Oxford provide models of excellence with high-quality buildings and urban spaces (Figure 1.1), while towns such as Brighton are exampl...

Table of contents

• Cover
• Halftitle
• Title
• Copyright
• Contents
• Foreword
• Preface
• Introduction: What is Urban Housing?
• Part One - ISSUES IN URBAN HOUSING
• Part Two - CASE STUDIES
• References
• Further Reading
• Index