London’s population density over a wide area is the highest among European and North American World Class Cities, but there are many different ways of measuring housing density.
Two of the most popular indicators of supply and density are households per hectare or habitable rooms per hectare, but even these measures can be erratic and not directly comparable. This makes them unreliable indicators of how intensively land is being used in London – and elsewhere.
The key to housing density measurement lies in what piece of land is being measured. The same location can have very different housing densities if the number of residential units on it are measured according to gross land (ie, all land for buildings, roads, rail shops, offices open space, water, etc) or according to net building area (ie, only the land upon which residential buildings stand).
This is a particularly important measure to understand when housing density is considered as part of planning criteria. The scale of development will be an important consideration to determine appropriate density; large, neighbourhood areas will need more infrastructure, open space and other uses than small, single-building sites.
Keeping in mind the factors that make London a successful place to live, work, play and visit, it is vital to measure density appropriately. Without all the other land uses, London would not be the premier world city that it is today. Provision has to be made for these uses, as well as housing, if new development is to emulate the success of existing neighbourhoods.
The highest density boroughs are generally in inner London. When all types of land are taken into account, Kensington and Chelsea houses the highest number of households per hectare – along with all the other commercial, retail, restaurants, bars, pubs, clubs, hotels, squares, gardens, parks and other land uses that the borough hosts.
Net domestic density is highest in Tower Hamlets, followed by Westminster. This is partly because dwelling size (the number of habitable rooms) per household is smaller. The lowest density boroughs are generally found in outer London, which tends to host larger houses on bigger plots and fewer mixed use neighbourhoods than inner London, so both gross density and net domestic density are lower.
A successful residential neighbourhood consists of very much more than just housing ‘units’. Successful development in well-connected locations may not be those with the highest density of housing but those with the greatest intensity of land use, able to cater for all the local needs of inhabitants, workers and visitors.
Read the full report: Population Density, Myth and Reality.