At the Sustainable Communities Summit next week, John Prescott will push his vision for high-density, low-rise solutions to the housing crisis. But this single-minded, traditional approach has limitations.
By dismissing high-rise options, it ignores the potential benefits of building tall.
Although low-rise offers considerable potential for increased densities and supports “preferred” designs, such as the “perimeter block” and traditional “street and squares”, such forms cannot always achieve the densities of high-rise models. And the traditional city plan form is not always the most appropriate model for every location.
Urban briefing and empirical modelling repeatedly suggest that densities above a certain threshold compromise outdoor space provision, reduce privacy, create overloading and affect climatic design parameters. Not even exemplar design can solve all these problems. DEGW’s own modelling has identified the threshold as an approximate plot ratio net of 1:1.8, or about 150 units a hectare.
Also, oversized groundscapers feel overcrowded beyond a certain density. This will affect who lives there, the capacity to change or remodel the development, as well as its long-term viability as valuable property.
Reluctance to explore high-rise residential models relates primarily to the failures of public-sector housing in the sixties and seventies and the perception that high-rise equals tower block — a building with a narrow footprint in relation to its height, of a single geometry and sited on open land.
The definition needs to be clearer. If the benchmark for the traditional European morphologies and street forms is a maximum of eight storeys (10 in Paris), then developments of 12, 15 or 18 storeys should also be labelled high-rise. They are still often presented as high-density, low-rise compact models, despite being a clear departure from traditional models. When buildings of this height are designed as traditional terraced block plans, they become monolithic and oversized, canyon-like spaces.
A planning policy without restrictions on building height would encourage the exploration of alternative models of less compact forms, and we might move closer to the elegant building configurations of the Continent.
More flexible high-rise options could meet a number of the objectives of the Sustainable Communities Plan. Space released at ground-floor level would allow for more generous outdoor activities and services, soft landscaping, more privacy across buildings, or just more “space”.
Flexible high-rise options could meet objectives of the Sustainable Communities Plan
Taller buildings can also create outdoor space at upper levels for community use or, more importantly, private spaces that would encourage new forms of family housing. At the same time, space between buildings and the separation between the ground and upper floors can reduce conflict between various uses — residential, work, leisure and retail.
Finally, higher buildings bring economic advantages, that, combined with additional city infrastructure, can support affordable housing, better services, and frameworks for long-term management and maintenance.
Some models are beginning to emerge in UK practice, such as the Cascades, Barrier Point and Chelsea Reach. Although their typological, architectural and contextual success varies, these schemes highlight the possibility of creating new building types.
Today, transport systems have a massive impact on urban form. The city, with its distinctive high-intensity centre, has been transformed through connections to sprawling metropolitan regions supported by multi-nodal service systems. But much of the urban design debate remains focused on the return of traditional values, urban structure and the visual language of the pre-20th century city.
Assessment of urban interventions such as high-rise can no longer be a simple “either or”. It must be more about what it is and where it would be appropriate
Lora Nicolaou is director of urban strategies at DEGW.