Planning: Suburban housing density
Pre-planning toolkit: Suburban character and high densities need not be mutually exclusive, writes Richard MacCormac
Housing developments in outer London are facing a dilemma.
The traditional expectation of suburbia is for low-density family housing set in leafy surroundings, but the Mayor’s London Plan and government policies to promote sustainability seek to maximise the residential capacity of land. This aspiration coincides with an increase in land values, which makes the economic viability of development depend on higher densities.
The urgent question then is how to reconcile these expectations with development densities, which may be three or four times higher than those that exist locally. There is real anxiety about this. For many, density signals overcrowding, tall buildings (with families off the ground) and the loss of open space and greenery. In short, an assault on the very idea of suburbia.
With my colleague Matteo Sarno at MJP Architects, I have researched possible answers to this question. The aim of the three studies illustrated here is to demonstrate how significantly higher densities can be achieved while still maintaining suburban character, forming an environment of mainly two- to three-storey houses with gardens and open space.
Although these studies are based on a real outer London site, they offer a methodology, a kind of toolkit, to enable local authorities and residents to visualise, at pre-planning stage, the effects of high residential densities on the character of suburban areas, and to show that this need not mean tall buildings and the loss of suburban amenities. This approach offers an instrument for empowering communities and influencing planning briefs.
The toolkit has been developed from the research report ‘Sustainable Suburbia’ supported by the Homes and Communities Agency (view it at www.sustainablesuburbia.co.uk). A crucial aspect of the report, which is central to our methodology, is matching residential typologies to specific densities, something that can be done for any part of the London Plan’s density matrix.
Peter Barber of Peter Barber Architects, who has reviewed our research, said: ‘I am fascinated by the use of terraced housing typologies for higher densities. I am dismayed at the direction proposed by the government, which appears to condone the spread of suburbia into the green belt.’
It is important to point out that each of our family housing typologies was designed to maximise density and effective land use. For example, the maximum density of detached housing was found to be about 35 dwellings per hectare, two-storey semi-detached and short terraces about 50dph, and mews housing about 80dph. For the purposes of this study, non-family apartments achieve a density of up to about 130dph, and are deliberately limited to a height of four to five storeys.
This relationship between densities and typologies enabled us to quickly investigate the options available. The three schematic proposals respond to a brief which includes a mix of family housing, apartments and park-like open spaces (see documents attached to this article for case studies).
In each case, the housing numbers, expressed graphically, are converted into land-use pie charts. Crucially, the effect of the reduced footprint of the apartments allows up to three-quarters of the development area to consist of family housing or open space. So, paradoxically, the higher the density of apartments, the more suburban most of the development will appear.
These options are only a snapshot of a range of possibilities, which with other typologies might add up to a typological inventory for suburbia. As Stephen Tapper, assistant director at LB Enfield says, ‘It enables clear trade-offs between mixed housing typologies, environment and density within sound urban design principles.’
This study questions how suburbia might redefine its values and character. This could bring together the traditional benefits of suburbia – house, garden, privacy, quiet – and the shared benefits of higher densities – viable public transport, access to local centres and schools, walkability, green infrastructure and allotments. All these things have implications for a future sense of community.