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Sustaining housing growth

Options for locating future housing, their sustainability and acceptability, were central to the latest Architecture Research Forum

The often-quoted figure of 4.4 million new dwellings needed in the next 25 years comes from a DoE report of 1995 1. Its particular 25 year period is from 1991 to 2016. An average of 176,000 new dwellings per year would be needed to achieve this total, the sort of volume we have been producing comfortably in recent years. And while there is talk of the government reforecasting this prediction upwards, this is still not to levels that would put a great strain on industry capacity. For the public, though, discussion of dwellings-by-the-million has helped to focus concerns about the location of future dwellings.

Where will they go?

One recurring issue of location is the hope of creating sustainable future settlements, though no one appears to have a robust definition of what a sustainable settlement is. A current study in Swindon, reported at the Forum by Phil Steadman (Open University) and consultant Peter Rickaby, is looking at some components of the sustainability picture, particularly trip-generation and fuel use. Though transport consumes less than half the energy used by buildings, it is the main area of energy consumption growth nationally.

With the NIMBY effect strong in Wiltshire, Swindon is likely to be the focus of a large part of growth in the county. A 40 per cent increase in households and a 46 per cent increase in employment are predicted over the next 25 years. Steadman and Rickaby are modelling the effects of location policies compared with the existing market. Three locations for growth are being explored:

concentration of growth in the centre of the town, incorporating brownfield land and increasing density as a relatively high-density town expansion area on the north-west periphery by expanding a series of towns and villages in Swindon's hinterland (see plans).

The whole study includes sustainability issues of air pollution, energy use in transport and buildings, plus the potential for renewables, materials recycling, and the improvement, equity, opportunities and accessibility of transport. Journeys and energy use are not related so much to overall size and density of a settlement as to the relative disposition of houses, work, leisure, etc. Transport tends to shape land use more than land use shapes transport.

Steadman and Rickaby see some strong constraints on making changes to location patterns. Late twentieth-century lifestyles do not fit readily into the romantic view of the compact city (R Rogers, please note). With building turnover of the order of one per cent per year, results will not come quickly. And our widely admired planning system is not a very strong instrument for effecting change.

Their three approaches - central densification, peripheral expansion or village expansion - all share some assumptions.

Mixed use will increase, potentially reducing trips. Improvements will occur in energy efficiency. There will be dedicated orbital and peripheral bus ways, cycle ways and improved public transport services.

(Orbital routes can make a significant difference to ease of movement. ) The dedicated routes reduce car capacity, particularly in the city centre; there is also park and ride.

From their modelling they are finding:

the land take is significantly higher for the peripheral expansion than the other two

transport fuel use and number of trips show just a little improvement in each case (and trips may be a bit shorter).

However, the small savings are overwhelmed by increases due to growth in households over the period. A shift of around 8 per cent from car to public transport is predicted, and a 13 per cent reduction in transport fuel use the increase in floor space due to growth is the main determinant of the town's future building energy use. A small (4 per cent) improvement in energy efficiency is predicted from higher density increasing density tends to drive out low-value residential uses and subvert the intention of promoting mixed use there is little scope to change travel patterns overall by land-use planning.

Transport policies have more effect, such as car restrictions and dedicated busways.

But population growth increases car use significantly overall 'compact city' policies are unlikely to reduce car travel or overall traffic significantly. Mixing land use is more effective, where it can be made to work the study is not looking at home-working, though results from the US indicate that this does not reduce car trips significantly in terms of equity, those on lowest incomes live in small dwellings and have little opportunity to change habits. Those best off can usually buy their way round restrictions by moving or paying any deterrent charges. Those on middle incomes appear to be potentially the most likely to respond to changes in transport and dwelling policies.

Intensifying land use Another project in progress, looking at the acceptability of intensification of urban land use, was reported by Mike Jenks of Oxford Brookes University. This is a large project, surveying 445 local authorities, many planners and national data sources such as the census; then homing in on 12 towns for detailed study.

The picture today is that about half of urban development is on land previously used. On balance most household moves are away from the urban core, though not all. There is extreme regional variation, both in the extent of development and reactions to it. Some areas see intensifying land use as a potential source of jobs, others as over-development. The most positive reactions were in areas with mixed urban/rural land uses and traditional urbanised manufacturing areas.

Most negative were London and the South-east, high-status areas, resorts and retirement areas. Not surprisingly areas with most development pressure were most negative.

From the detailed case studies of households, there was often a mixed reaction to land-use intensification, by no means unthinkingly NIMBY. Some respondents see benefits in intensification, such as :

improvements in design quality overall upgrading of the area vacant sites occupied existing facilities improved.

people still like living in their areas after intensification planners and visitors to the area are often more positive.

But people also see disadvantages to intensification, such as: more pollution more traffic and parking problems sometimes poor design loss of local character social change overdevelopment.

Broadly, intensification can be OK if it is well-defined, on derelict land or uses dead areas. It is not OK if it is large, nonresidential, reduces amenity, brings in anti-social uses and changes the social make-up of the area. An analysis of the respondents shows the young and mobile who rent are most positive about intensification. The most negative are the old and those in social classes I and II.

Jenks currently draws two broad conclusions. Any land-use intensification is so affected by its context that you cannot come up with a golden formula for acceptable intensifications. But there is a lot you can do to make them more acceptable.

Keeping up housing densities As David Levitt of Levitt Bernstein Associates commented, density can be a problem word, pejorative and linked to poverty. Trying to attract the better-off into the inner cities is an uphill struggle, which must involve better schools, better transport and better security as much as better building design.

One issue in urban density is highrise living, or at least not knocking down the urban high-rises that already exist.

In one redevelopment scheme, the idea was to take down all the high-rises, but discussions with residents found that many older people like high-rise living as long as the lifts and security work. So one block is to be retained for them, including shops and communal facilities for the estate. (In other cities former public tower blocks have been used for student housing. ) Levitt also drew a contrast with a 1960s area with private low-rise close to unpopular local authority tower blocks. A new proposal for redevelopment of a similar area reverses this - the low rise is social housing while the medium-rise towers at the corners of the site could be for sale or rent to the private sector. These private occupiers are the people who can better afford the building management to make higher-rise work.

Replacing the stock Simon Pepper from Liverpool University pointed out that one area of construction activity missing from the current housing debate is replacing the existing stock. The shift from clearance to housing rehabilitation in the 1970s made demolition almost a taboo subject. Demolitions have fallen to around 6-9000 per year. For this to continue indefinitely, the average life of a dwelling would need to be around 250 years. Clearly few current dwellings will make it. If average dwelling life were, say, 200 years, we would be replacing an average of 100,000 dwellings per year from the 20,000,000 English housing stock.

For how long houses can or will be made to last needs to be part of the current national debate. Pepper notes that:

the UK, along with Ireland and Belgium, has the oldest housing stock in Europe. About 25 per cent is pre-1914, 20 per cent inter-war. House condition surveys show that poor condition relates directly to age of dwelling as a former insider, Pepper believes official condition surveys underestimate national disrepair the poorest housing is disproportionally in the private sector, both owneroccupied and privately rented, especially in rural areas. This private ownership makes central intervention difficult many of the first phase of post-war refurbishments are approaching the end of their planned life.

Nor should we assume that dwel ling replacement is outside the location debate. Will every dwelling demolished really be replaced by another one on the same site? Or will some existing areas be found too unattractive at existing densities, or as housing locations at all? Will some existing sites be too highly valued for continued housing use? The debate continues.

* Projections of Households in England to 2016. DoE. HMSO. 1995. 100pp. £45.

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