The Mayor of London commissioned LSE London research on housing density. This research data is meant to aid in the development of policies and preparation of the London Plan. Links to all of the reports can be found here.
LSE London’s Christine Whitehead, Alan Mace, and Ian Gordon wrote two out of the the five reports. The first report titled, ‘Defining, measuring and implementing density standards in London’ (London Plan Density Research Project 1), was written by Ian Gordon, Alan Mace, and Christine Whitehead, can be found here. The second report titled, ‘Why else is density important?’ (London Plan Density Research Project 5).
Here you can find the snippets of the executive summary to both of the reports:
Executive Summary Defining density
- This project explores the various definitions of density and the different methods by which it can be measured. It considers which approaches best provide an understanding of two key issues: urban form and the number of people in an area.
- The main reasons for using and measuring density include helping to ensure that (i) housing is available for the population; (ii) what is built is suitable both of itself and in relation to the surrounding areas; (iii) households can access services, infrastructure and employment, and (iv) available services and infrastructure are effectively used and planned for the future.
- The London Plan has always taken as read that the main objective is to densify in order to provide housing for the growing population within the London boundary. Because of rapid growth that is expected to continue to be the most important objective.
- The measures used in planning documents across the spectrum of land use planning systems vary somewhat but in the residential context come down three main categories:
- Numbers – including numbers of dwellings, numbers of rooms (habitable rooms, bedrooms, bed spaces), square metres or equivalent;
- Built form – which at its simplest tends to be based on plot ratios and other physical relationships between land and building; but also includes type of area (as in the London Plan’s central, urban and suburban); tallness of buildings and other standards;
- Person based measures such as persons per hectare.
- Numbers are generally used to achieve the homes required; built form to specify design and the local environment; and persons to clarify requirements for existing and planned service and infrastructure provision.
- An additional complication is that measures may use either net and gross densities – and identify these in different ways.
- Planning densities – i.e. ones related to buildings rather than people – cannot directly impact on people-based service and infrastructure requirements. These depend on the use made of the buildings provided.
- Most of the available data in London relate to numbers – notably the number of units and the number of bedrooms. Aspects of built form and environment are measured in a more qualitative fashion. Material on accessibility and connectivity is available and used through the summary PTAL measure.
- The current London Plan’s objective of optimising densities is directed essentially at securing a number of additional dwellings within London that is closer to the housing supply target, while sustaining appropriate residential quality and accessibility in the neighbourhoods where development would occur;
- Other salient concerns which might also be assisted by higher density standards for new development include: enhancing economic productivity, encouraging more sustainable patterns of travel, facilitating a more suitable mix of new dwellings and increasing occupational densities to support a more productive workforce.
- Encouraging higher densities within new developments may contribute to these other policy goals via two distinct routes: by raising overall population and density levels across the metropolis as a whole (the macro-route); and/or by achieving those outcomes within specific local areas where they would yield particularly positive effects (the micro-route).
- Housing type and tenure initiatives depend mainly on the micro – route, while for the potential productivity and travel sustainability effects there are both micro – and macro – routes to be considered.
- For the macro – type impacts, the relevant region across which increases in the scale/density of activity are relevant to economic productivity and/or environmental sustainability may extend well beyond the GLA area covered by the London Plan.