building for life - better neighbour hoods. making higher densities work - literature review

8/8/2019 Building for Life - Better Neighbour Hoods. Making Higher Densities Work - Literature Review

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• The plan seeks to ensure that new higher densityhousing is appropriately located in places with adequatepublic transport accessibility and capacity. New inlldevelopment should be sensitive to the character ofexisting areas and not simply reproduce prevailingdensities. Para 3A.24

• The Mayor will and boroughs should ensure developmentproposals achieve the highest possible intensity of usecompatible with local context, the design principles inPolicy 4B1 and with public transport capacity. Boroughsshould develop residential and commercial densitypolicies in their UDP’s in line with this policy. Residentialdevelopment should conform to the density ranges inTable 4B.1. The Mayor will refuse permission for strategicreferrals that under-use the potential of the site. Policy4B.3

• The Mayor will expect a maximum contribution towardshousing provision to be achieved by checking that UDPreviews and planning applications referred to him arein conformity with the density matrix in Table 4B.1.

The density matrix sets a strategic framework forappropriate densities at different locations. It aims toreect and enhance existing local character by relatingthe accessibility of an area to an area to appropriatedevelopment and the number of car parking spaces thatshould be provided. Para 4B.15

• The matrix is not static as it provides a tool for increasingdensity in situations where transport proposals willchange the public transport accessibility ranking. Suchchanges allow a shift to a higher density range. Para4B.17

• The compact city and intensive development doesnot necessarily imply high rise buildings. London hasachieved some of its highest residential densities inrelatively low rise areas, while isolated, poorly designedtower blocks have not necessarily delivered high densityor usable public space. Para 4B.23



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15 Land for Housing: Current Practice andFuture OptionsBarlow, J. Bartlett, K. Hooper A. andWhitehead C. YPS in association with theJoseph Rowntree Foundation, 2002

Whilst there is an emerging consensus about housing

production and land supply the authors of this report areconcerned that in a number of critical areas the emergingpolicy framework is based on over-optimistic assumptions.They question whether policy will deliver the necessarysupply of houses to meet the UK’s economic and socialrequirements over the next 20 years.

The assumptions they consider are most open to questionare:

• The level and nature of demand – numbers, affordabilityand location;

• The capacity of the chosen options to meet housingdemand in the timescale required. This relates to boththe narrow focus of the current debate over browneldor greeneld development and the lack of an appropriatesystem for regional territorial management.

“The recommendations of PPG3 and the Urban Task Forceseem not to take sufcient account of the macro-economicagenda of the UK, which is likely to require houses to bebuilt where they may be politically unwelcome. An approachbased on exhortation works well only where there is basicagreement about objectives and where the projectedsolutions are good investments for relevant decision makers.

The extent of the confrontation between existing residentsand people looking for new homes appears not to have beentaken sufciently seriously.

Restricting additional dwellings to browneld and greeneldsites is too narrow. We must nd ways of redeveloping moreeffectively land in strategic areas now occupied by low-density, poor-quality housing.”

The report assess the level of demand in the South-east andrelated levels of housebuilding in recent years:

“Two key issues need to be addressed – are housing demandnumbers accurate and is the government prepared torecognise the requirement and enable the dwellings to bebuilt?



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Matrix Table 4B.1 Car ParkingProvision

High

2 – 1.5 spacesper unit

Moderate

1.5 – 1 spaceper unit

Low

Less than 1space per unit

Predomin-anthousing type

Detached andlinked houses

Terracedhouses & ats

Mostly ats

Location AccessibilityIndex

Setting

Sites within 10mins walkingdistance of atown centre

6 to 4 Central 650-1100 hr/ha240-435 u/haAve. 2.7hr/u

Urban 200-450 hr/ha55-175 u/haAve. 3.1 hr/u

450-700 hr/ha165-275 u/haAve. 3.0hr/u

Suburban 200-300 hr/ha50-110 u/haAve.3.7 hr/u

250-350 hr/ha80-120 u/haAve. 3.0hr/u

Sites alongtransportcorridors &Sites close to atown centre

3 to 2 Urban 200-300 hr/ha50-110 u/haAve.3.7 hr/u

300-450 hr/ha100-150 u/haAve. 3.0hr/u

Suburban 150-200 hr/ha30-65 u/haAve. 4.4hr/u

200-250hr/ha50-80 u/haAve. 3.8hr/u

Currentlyremote sites

2 to 1 Suburban 150-200 hr/ha30-50 u/haAve. 4.6hr/u



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Migration pressure will be concentrated in the South and,particularly, London. Some two-thirds of the growth inhousehold numbers is expected to be in southern England,with 20% concentrated in London.”

Important points are made in relation to demand for space

“Income elasticity with respect to housing space is relativelyhigh, hence the most obvious way in which demand pressure

might be reduced is through economic recession. Even ifthe trend towards living alone were reversed, which seemsunlikely, the demand for space – both housing and land – willcontinue to increase unless incomes do not rise. And evenif income growth is limited to around 2% per annum, over20 years households with the capacity to pay are likely todemand nearly 50% more space than current standards.This demand would be reinforced if trends towards homeworking, entertainment and health and social care progressas expected.”

The report also recognises the impact that increasingdensities could have:

“… an overall modest increase in densities in newdevelopments and in existing areas would be sufcient tomeet the need for new homes. Densities of 30-50dph asrecommended in PPG3 do not rule out higher densities inappropriate locations. However, insufcient attention hasbeen paid to the fact that general regulations and practice ondensity in the UK are out of line with the recommendationsof PPG3. In many areas there is little political will to increasedensities, rather the reverse. Many local authorities wouldwelcome a stalemate on the density issue which blocksdevelopment altogether.”

However the report points out the danger of increasingdensities without due regard for other issues:

• “Care should be taken not to promote dramaticincreases in density solely for the sake of numbers.Raising densities in the absence of design innovationcarries the danger of recreating the cramped and poorhousing environments that the last 50 years have slowlyoverturned.

• Arguments for density urgently need to be tested againstactual consumer preference: anything less will lead to

architectural determinism.• Experience in existing developments has clearly shown

that, in the UK, the socio-economic status of residentsis a critical density issue because the number of people



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actually resident in similar-sized houses varies acrossdifferent socio-economic groups by more than 100%.Similarly the amount of time people spend within thehome also varies widely according to age and socio-economic status.

• It is to be welcomed that building regulations are beingstrengthened to deal with the effect of higher densitieson noise levels between and within homes.”

The report concludes that the housing supply systems isfacing three critical challenges:

1. To redesign the planning system to meet additionalrequirements when and where they arise

2. To begin the process of reducing the average age ofBritain’s housing stock and raising overall housingquality by replacing outdated and often low-densityhomes that are uneconomic to refurbish

3. To provide affordable housing to those who are unable tosecure homes in the open market or ineligible for social

rented housingThe report doubts that existing mechanisms for improvingthe supply of housing will be effective unless land andredevelopment uses are properly addressed particularly as‘current policy relies on exhortation’.

The report recommends the following:• “Discussion about the supply of new housing land must

move away from the narrow ‘browneld vs. greeneld’debate and take account the macro-economic needs ofthe UK and the sustainability of both and rural locations.Increasing housing densities to avoid developmenton greeneld land may well be incompatible with thehousing space needs of the 21st century

• Higher densities must be accompanied by innovation inhousing design and building regulations

• An important aid to reducing housing affordabilityproblems would be mechanisms that address the priceof land

• There is the need to reform planning practice withinlocal authorities so that planning policy and developmentcontrol are brought together and the reactivedevelopment control culture of planners is overcome”

Finally, the report advocates a shift towards a balancedapproach to housing and economic development bypoliticians in order to achieve the proactive territorialmanagement of space.



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16 Delivering Urban Renaissance in theSouth East: Overcoming FinancialBarriers to Browneld DevelopmentRICS South East Region in associationwith the South East England RegionalAssembly, 2002

This report considers the nancial and scal barriers to thedelivery of large browneld urban development schemes inthe South East based on an examination of ve case studies.The case studies were located in Brighton, High Wycombe,Shoreham, Dover and Rochester.

The report provides a useful assessment of the practicaldifculties of browneld development and, in the contextof the South East particularly in respect of the potentialenabling role of SEEDA, the local RDA. The reportrecommends several practical solutions as well assuggesting changes in policy.

The report concludes that the development of browneldsites is often complex and there are many different causesof viability problems that give rise to nancial barriers. It isimportant to understand these causes in order to considerthe nancial constraints and measures to overcome them.Land assembly is considered to be a major barrier becauseof landowners’ unreasonable expectations of value. Apossible response is for RDAs and local authorities topromote more widespread use of Compulsory PurchaseOrders (CPOs) and for RDAs and local authorities to beprovided with adequate funding to enable them to acquire keysites.

Key points and recommendations include:

• Land ownership is a barrier - CPOs need to be morewidely used to overcome this. Ultimately, landowners’expectations of value may continue to frustrate/delaybrowneld redevelopment.

• Mechanisms are needed to ensure the rapid release ofsurplus land owned by public agencies and statutoryundertakers.

• SEEDA should take a lead role in the use of CPOs and

offer guidance and support to local authorities. Localauthorities will need to become more proactive in the useof their statutory powers, particularly regarding smallsites.



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• There is a skills shortage among practitioners inunderstanding the viability issues associated with thedevelopment of browneld sites and the complex trade-off between planning ideals and viability necessary forprojects to be delivered. The shortage applies to thedevelopment industry and local authorities.

• In regeneration situations that have abnormally highcosts and no public funding, local authorities haveto compromise on their urban renaissance ideals.Understanding the viability issues is essential toensuring that the proper trade-offs are made.

• Clear planning guidance is essential to encourage privatesector condence. Lengthy local plan review periodshave not been helpful but site-specic developmentbriefs have proved benecial.

• More partnership work is needed between localauthorities and developers and SEEDA.

• Gap funding under current EU rules is ineffective. It isonly available in certain areas and the ‘aid intensity’ levelis not high enough to make it worthwhile to developers.

• Direct development (i.e. site assembly and sitepreparation) by SEEDA is an effective tool but it hascashow implications requiring up front investment.

• Direct development is unlikely to be the panacea for thedevelopment of smaller inll sites except longer-termstrategic projects or those that may act as a catalyst forwider regeneration.

• More use could be made of joint ventures with a moreproactive approach by local authorities. SEEDA may havean advisory role here; also English Partnerships (EP),particularly in relation to delivering affordable housing.Special purpose vehicles (SPVs) delivering area-wideregeneration programmes have a role to play in someareas. The Spatial Development Company establishedby SEEDA, Kent CC and East Kent districts is perhapsthe most advanced. It is managing a programme to fundthe shortfall in mains utilities in an area of East Kent,thereby lifting a major barrier to the development ofemployment land in the area.

• Outside high value areas higher density developmentdoes not necessarily equate to higher value. There comesa point where higher densities can cause schemes to

become unviable due to additional costs of constructionexceeding additional value generated and consequentlyimpacts negatively on land values. This needs to beunderstood by local planning authorities. Also, thatsome compromise on urban renaissance ideals may



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be necessary for a project to proceed. Neverthelessthe case studies provided evidence of developer-ledproposals at residential densities of 40-70dph, whichmeets and exceeds the guidelines in PPG3.

• Commercial operators, developers and investors havegenerally been slow to respond to the urban renaissanceagenda due to the higher risks and uncertaintiessurrounding timescales, particularly for the larger sites.

• Development companies are risk-averse towardstackling long term, complex browneld projects,particularly where there are high up front costs. Thesecosts could be reduced by public sector investment inland assembly and site preparation. The developmentindustry is wary about projects requiring grant aid, whichis perceived as bureaucratic with the potential to causedelays and uncertainty. Grant aid programmes needsimplicity and consistency.

• Practitioners said that landll tax could be a deterrent tobrowneld development. In some cases could it tip thebalance between viable and non-viable schemes.

• An extension of stamp duty relief was the mainscal benet promoted by both developers and localauthorities.

• The CPO process is too long, complex and expensive.Uncertainties over the valuation of properties to becompulsory purchased can deter developers fromoffering CPO indemnities. Where this occurs RDAs andlocal authorities will need to consider taking on therisks of site acquisition. There are risks associated withthe CPO process. A possible response is early nancialanalysis, a funding strategy prior to starting a CPO and

robust delivery. Risk management, improved training andaccess to specialist advice are needed

• Local authorities are short of CPO skills, experience andresources. Training and dissemination of best practicewill be important to address skills decit. Funding will beneeded for public sector-led land assembly.

• There can be delays in reaching agreement on saleterms between public agencies. More frequent use ofDV valuations should be promoted. Surplus land ownedby public agencies/statutory undertakers is taking toolong to be released for development. The causes andpossible mechanisms to improve the situation need to beexamined.

• Land assembly will sometimes involve relocation ofbusinesses/households. Local authorities and RDAs



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should be encouraged to act proactively to facilitaterelocations.

• Where there are high abnormal costs associated withbrowneld development and no public sector fundingis available, compromise on the mix of uses is neededto achieve viability. Those negotiating the planningapplication will need to improve there understanding ofviability issues.

• Early site investigations are essential but represent ahigh risk to developers. Where justied the public sectorshould consider risk sharing of site investigation costs.

• The Environment Agency’s (EA) ood protectionrequirements add signicantly, in some cases, to afunding gap. Where this arises consider funding from EAsources. The EA’s inconsistent approach to remediationstandards across the regions is creating uncertainty inthe market place. This issue needs to be reviewed

• Delays in the planning system are frustrating brownelddevelopment, particularly the plan review process. Thereis also the risk of poor local authority decision-makingdue to a lack of member understanding of browneldredevelopment issues. Education and training areneeded.

• Complex analysis is required to understand viabilityissues. Expert advice is needed on urban design anddeliverability. Suggestions include (a) extending the roleof CABE or architecture centres to address broaderissues concerning browneld development than justdesign (b) provide additional resources to SEEDA toprovide advice (c) set up a not for prot advisory serviceto local authorities.

• Requirements for affordable housing are often not clearcreating uncertainties for developers. Clear guidance anddenitions of affordable housing are needed.

• Developers can be reticent about adopting a truepartnership approach. More openness and transparencywould help local planning authorities’ assessment ofviability.

• There is a lack of operator and investor exibility tocompromise accommodation requirements. A culturalshift is needed.

• The development industry is not very adept at appraisingcomplex, mixed-use, browneld developments. Theprofessions can play a role in upskilling practitioners.Evaluation skills are needed to test the robustness ofproposals at an early stage to avoid abortive work and



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delays.

• Development companies are risk averse towardstackling long-term, complex, browneld projectsparticularly where there are high up-front costs. Theserisks could be reduced by public sector investment incompleting land assembly and funding other essentialsite preparation costs. A possible response is directdevelopment and essential pump-priming of brownelddevelopment sites.

• Local authorities tend to respond to developers’proposals, which often mean the LAs are starting on theback foot. They should be proactive if they are to achievepositive results. This will have resource implications.

17 Better Places to Live: By Design – Acompanion guide to PPG3. CABE, ODPM, Thomas TelfordPublishers, 2001

The study focuses on the attributes that underlie well-designed, successful residential environments. It examinescase studies of contemporary developments and places thathave stood the test of time in order to illustrate that betterattention to good design can enhance the quality of life ofresidents. It seeks to be a companion guide to PPG3 andis aimed at all those involved in the planning, design anddevelopment of new housing. It is especially relevant tohousing within the density range of 30 to 50 dwellings perhectare.

It considers that:

“The greatest challenge to current practice lies in improvingthe quality of the ‘anywhere, everywhere’ residentialenvironments that, typically, have been built at around 20-25dwellings per hectare.”

The report provides useful analysis of the issues surroundingthe successful design of places covering a hierarchy ofdesign issues from movement networks, public realmthrough to block design and construction related issues.

It recommends that the quality of new housing dependson movement networks designed to consider a range of

issues including integration into existing routes, provision ofmaximum route and modal choice, routes which reinforcecharacter, the location of shops and services, frequencyof access points into the development, convenience forpedestrians and cyclists, clear views and easy orientation,



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trafc dispersal, and the ability for long term change.

“There is no standard formula for designing such layouts;much will depend on the local context (including securityissues) and how the development relates to existing areas.”

The report also covers the design of housing andrecommends that perimeter blocks are an efcient design,are legible and allow for good connections to the surrounding

area. It is also easier to distinguish between the public andprivate realm and provide for natural surveillance of thestreet. Block dimensions can make efcient use of land andadd richness to a neighbourhood. Key considerations includebalancing efciency with the need for convenient pedestrianroutes, trafc management and the spatial needs of activitieswhich are to be accommodated within the block.

Modern construction methods can improve space standardsby allowing broader spans for easier internal spaceconguration.

“…steel and concrete frame construction can create broaderspans which make the reconguration of internal spaceeasier than where dwellings are built in a cellular formwith load bearing walls; vertical stacking of kitchens andbathrooms can simplify the provision of additional services;compact vertical circulation with ready means of escapecan make larger homes more suitable for subdivision intoapartments or commercial use; use of solid oors canreduce noise transmission.”

The importance of good quality public realm is covered inseveral publications, this report considers that public realmquality can be undermined through lack of planning and

unrealistic budgets:

• “The lack of a full landscape plan an specication aspart of the design of the scheme submitted for planningapproval;

• Inadequate and unrealistic budgets for external works,particularly for hard and soft landscape;

• A tendency for the budgets for these items to be reducedin an attempt to cover over-runs in work undertakenearlier in the construction process;

• The problems of accommodating late additions,especially those required by the adoption agencies”



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18 Housing Design Quality: through policyguidance and reviewCarmona, Matthew, E & FN Spon, 2001

This book evaluates current practice and innovation in thelocal authority control of private sector residential designthrough the English planning process. It is written in thelight of increasing pressure for new residential development

alongside increasing condemnation of the standardproducts of the volume housebuilders and the frequentlyunimaginative attempts of the public sector to inuence thedesign of such development. Key points are summarisedbelow:

The key to any long-term improvement in residential designis likely to lie in the process of delivering new residentialdevelopment – in the structuring of the housing market, inthe process of the allocation of land through the planningsystem, in the motivations of the different stakeholders indelivering new housing and in the different perceptions about

the product actually delivered.Housebuilders argue that they know their market, that levelsof owner satisfaction are likely to be very high and that realimprovements in design cost money, which purchasers arenot willing to pay for. But in an environment of tight protmargins the extra money can only come from the pricepaid for land – which the current land market and planningsystem both mitigate against.

The study provides a useful assessment of the attitudesof the various stakeholders involved in the developmentprocess: “The range of stakeholders involved in the newresidential development will often be more complex thanmight at rst sight be apparent:

• Housebuilders are driven by prot. Their concern fordesign stretches only as far as their marketing strategiesallow or as far as better design results in higher salesvalues or faster statutory approvals. The product is thehouse and only to a lesser extent the context it denes..The simplest way to judge what sells is to repeat whatsold before.

• House buyers are concerned that the investment intheir house will be good until it is time for them to sell(frequently not very long). Such decisions are driven bycost, value for money, the functionality of the house andits size; by its location and only after that by its intrinsicdesign. Innovation in house design is rarely a desirable



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feature , largely because resale is often foremost in thebuyer’s mind and universality helps to guarantee a readymarket.

• Funders care little about the product except that its valuewill adequately secure the loan and offers a good returnon its investment. Traditional construction is often aprerequisite.

• Planning authorities (planners and councillors) areconcerned for the wider public (and political) interest,including protection of the environment. But they are alsounder pressure from both housebuilders and centralgovernment to release land. Design is a concern but onethat can be swept aside for bureaucratic convenience andother planning demands (e.g. economic development orachievement of basic residential amenity).

• Highway authorities are primarily concerned withfunctional operation (particularly safety and trafcow) of the roads and footpaths that they will berequired to adopt. Highway authority requirementscarry considerable weight for developers anxious toavoid the nancial penalties of non-adoption. Often thequickest way to achieve this is to follow any publishedstandards to the letter, making this aspect of the designa mathematical rather than a creative process. Intrinsicenvironmental quality is only of marginal importance.

• For re and emergency services, direct and ready accessto individual buildings and efcient movement through anestate is their only concern.

• Crime prevention ofcers value better design becauseit can reduce the circumstances for crime to occur. Inpursuing this, the argument has often been dogmatic.

• Building controllers have an indirect impact onaesthetics, choice of materials, layout, etc by the policingof the Building Regulations. Like the crime prevention,re and highways ofcers, this control is largely basedon standard rules and is often inexible.

• Established residential communities and amenitygroups generally favour no development but, if it is to beallowed, favour development that respects the existingenvironment and impacts as little as possible on thesurroundings. They have little direct power to inuencedesign outcomes.

• Design professionals (particularly architects) deplore thestate of speculative housing design but have been largelyexcluded from the mainstream residential market.Industrialisation and standard house types/layouts



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perpetuate this exclusion.

• For landowners, maximum prot necessitates minimuminterference (including in design) by the statutoryauthorities, particularly where each requirement by theplanning system potentially cuts into the value of theirland.

• Central government, like local government, will needto balance the competing objectives to ensure the

successful operation of the market while at the sametime limiting environmental damage and opposition tonew residential development”.

Other key points include:

• Bearing in mind the high cost of delay it is of the utmostimportance to housebuilders that houses are completedand sold as soon as possible, hence the heavy relianceupon well tried and tested formulae. The result is housesto standard designs. This poses particular problemsin seeking to recreate the complexity of the traditionalstreet scene or in promoting mixed-use developments.

The usual response has been to bring suburban housetypes into the cities.

• Just as housebuilders have not always been responsiveto consumer choice, neither have the government orlocal authorities in their guidance. For example, the mostfamous British guide – the Essex Design Guide of 1973– was never based on any survey of residents’ opinions

• The tendency is for owner-occupiers to remain uncriticalof their housing. This might be partly explained by theunique attitude of the British towards home ownership,where societal norms pressure people to struggle ontothe housing ladder. The result is that purchasers buyfor the short term, hoping that what they buy will be astepping stone to something better – and usually bigger –in the near future. Thus, issues such as space standards,energy efciency and even environmental quality becomesecondary concerns to the desire to buy and to benetfrom the endemic house price ination.

• Public intervention is the only answer to reduce volatilityin new housing markets, lower the focus on landdevelopment prots, subsidise innovations in housingproduction and provide a regulatory regime that is moreinnovation friendly.

• Planning authorities need to have an in-depthunderstanding of the processes that give rise tospeculatively-built housing environments, as wellas taking a view about the desired end products. In



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particular, planning authorities need to understand thatthe perceptions of housebuilders are largely determinedby the prot motive and by manufacturing and marketconstraints.

• To housebuilders the product is the individual house,and standardisation and conservative approaches todesign are the logical responses to uncertainty. Similarlyto house buyers, price, location and value, rather thandesign are often the primary concerns driving decision-making, while unsustainable modes of living remainoverwhelmingly the choice of most buyers of newhousing.

• The need is for processes that deliver desired designoutcomes by combining early ‘positive’ intervention withrealistic market assumptions.

19 Affordable Housing in London, SDSTechnical Report 1Three Dragons with the Centre for

Residential Development, NottinghamTrent University for the Greater LondonAuthority, 2001

This report, commissioned to help in the preparation ofthe GLA’s Spatial Development Strategy, is a study of thesupply and potential supply of affordable housing acrossLondon. An important output of the study, described inthe report, is a model that estimates the nancial viabilityof affordable housing delivery in each of the 33 Londonboroughs. The report shows that a 50% affordable housingtarget is achievable in new build housing in London; however,increased public subsidy will be necessary for the majority ofboroughs to deliver their affordable housing targets.

The Three Dragons Model can be used as an aid to decisionmaking and securing the appropriate amount of affordablehousing on a scheme – aiming to provide a system forplanners to insist on more affordable housing than isrealistic nor losing an opportunity to secure more affordablehousing. Key ndings are as follows:

• There is no borough in London where the density fallsbelow the recommended minimum given in PPG3

Housing• There is a high degree of association between house

prices and the viability of affordable housing delivery.High house prices tend to be associated with a high



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degree of viability of affordable housing delivery and lowhouse prices with a lower degree of viability. Density alsohas an effect on viability. Higher density developmenttends, other things being equal, to increase viability4

• Building (construction) costs are the major cost factorfor a developer, excluding the price of land

• A higher proportion of key worker rented accommodationproduces a modest increase in residual in the higher TCI

band boroughs. This is so because key worker rentedhousing receives no public subsidy and capitalised rentlevels are slightly more favourable than in the lower TCIboroughs

• No rm evidence has been found to suggest that mixingtenures has a potential depressing effect on the price ofthe market housing

• Residual values are very sensitive to house prices and, asmight be expected, the higher the proportion of markethousing in a development mix the greater the impact ofhouse prices on residual value. The lower the base houseprice and the closer it is to TCI the more signicant theproportionate effect on residual values of any increase inhouse price.

• Residual values are very sensitive to changes in houseprice and density. Change in the mix of affordablehousing tenures have far less impact, whilst the costsof dealing with special site development costs (e.g.decontamination) and other planning obligations canmake a big difference to the residual values

• Changes in the density of development have a markedeffect on residual values; increasing densities has moreimpact on residual values at 35% affordable housing thanat 50% affordable housing. However in both cases theimpact on residuals is positive and broadly consistent

• Higher density development could improve residualvalues and the ‘ability’ of sites to deliver affordablehousing

• In ‘low price’ boroughs, some new market housing maybe sufciently low in price (and/or could be specicallydiscounted) to provide an additional supply of housing tomeet the housing needs of households on lower incomes.This would to be assessed through borough localhousing needs assessments.

• The amount of public subsidy available inuences bothoverall delivery of affordable housing and the type ofaffordable housing provided as the terms on which publicfunding is available set a ‘going rate’ for payment by



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RSL’s to developers for affordable housing.

• The need for public subsidy is greater in the low marketvalue boroughs than in the high value ones because theability of the residual to absorb the cost of affordablehousing provision is more limited in low value areas

• Where commercial land use is a direct alternative toresidential development, commercial residuals generallyexceed those for residential development and affordable

housing elements fur ther reduces the attractiveness ofresidential development. Low housing residual valuesand affordable housing targets for residential sitesincrease the attractiveness of alternative commercialdevelopment. This is a factor that should be taken intoaccount when framing and applying planning policy.

• The ‘Exceptions Approach’ essentially allows only 100%affordable housing on certain types of sites promotedby the private sector. Where it has been adopted, thecommon approach has been to say that change of usefrom commercial (employment) land to residentialuse can only occur if that residential use is affordablehousing

• There is potential that commercial developments couldmake provision for affordable housing either on site orthrough payment in lieu

• Possibly small sites should no longer be exempt fromaffordable housing contributions if contributionsare required from both large residential sites andcommercial sites.

• Over half the London boroughs could deliver 35%affordable housing without public subsidy

20 Releasing Brownelds Syms P. Shefeld Hallam University,Joseph Rowntree Foundation, RICSFoundation 2001

The research focuses on the problems associated withbringing about the regeneration of towns and cities,particularly the physical, social, environmental andeconomic issues that may hinder delay or even encouragethe redevelopment of previously used land.

The aims of the research were to:

• Identify the issues that inhibit the release of browneldland for redevelopment;



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• Consider the mechanisms that need to be put in placeto ensure that site assembly problems do not prevent ordelay regeneration;

• Review ways in which information concerning the risksmay best be conveyed.

The study concluded that when a development projectinvolves the redevelopment of previously used land it isnecessary to consider a wider range of factors than for agreeneld site in order to arrive at the right decision. Theresearch identied six groups of decision-making factors asbeing relevant:

1. Site-specic factors;2. Communication considerations;3. Transport considerations;4. Special environmental factors;5. Risk assessment factors;6. Further considerations (eg taxes and limitations on land

use).The study makes some important points relating to

infrastructure and landownership which are summarisedbelow:

• In some cases the potential environmental impact ofthe transport aspects may outweigh site remediationbenets.

• From a developer’s perspective nancial viability islikely to be the prime consideration closely followed byenvironmental issues. On how to manage supply, thesuitability of existing infrastructure and the availability ofnew services may be crucial.

• Whilst development proposals are sometimes frustratedby the intransigence of landowners in holding out for highprices, developers would be reluctant to see a weakeningof the rights of land ownership.



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21 Building Homes on Used Land. Syms P. and Knight P. Shefeld Hallam.University, Joseph Rowntree Foundation,2000

The study examines ten case studies in order to provideuseful lessons for housing developers when tacklingpreviously-used land. Potential occupiers who were askedwhether they would be prepared to live in homes built onpreviously contaminated land said they would wish to beinformed about histories and remediation measures. Thestudy emphasises the complex issues that developers ofbrowneld land may have to face including undergroundobstructions, road closures/diversions, site assembly, thirdparty rights, party wall issues, provision of services and badneighbour uses on adjoining site.

It is worth noting the 11 stage process that the studyrecommends is followed when redeveloping contaminatedland. This is included below for easy reference.

“ Every site is unique and developers, their consultantsand regulatory bodies need to be aware that the solutionadopted in one situation may be totally unsuitable in another.The redevelopment process applied to contaminated landconsists of 11 distinct phases of development, many of whichare interdependent. The phases apply whether the developeris a housebuilder, housing association or public authority,although the emphasis on the individual phases may differ.The phases are:

1. Project Inception. Developers and regulators mustbe prepared to act in a exible manner to achieve theredevelopment of previously used or browneld land.

2. Site acquisition and assembly. Landowners may haveunrealistic ideas about the value of their land but,equally, they may be trapped by historic valuations andthe fact that the land is used as collateral against bankloans. Letters of intent, conditional contracts, etc mustbe carefully worded clearly identifying who is to do whatand who is responsible for what.

3. Site assessment. Identify any access or site constraints,including the adequacy of infrastructure, that may affectthe development.

4. Contaminant–pathway-receptor. All possible linkagesshould be considered. Note it may not be necessary toremove all contaminants from the site, it may be possibleto break or remove the pathway instead.



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5. Detailed design. Examine the layout of the site and beprepared to consider alternative remediation strategiesgiven different layouts.

6. Feasibility study. After the site assessment, havingidentied all potential pollutant linkages, the reviseddesign should be the subject of a comprehensive review.

7. Planning and regulatory approvals. Close liaison with theregulators during the earlier phases should ensure that

the necessary information has been collected and canbe presented in support of the applications. The need forwaste management or mobile plant licences should beidentied as early as possible.

8. Development nance. Banks are probably more preparedto provide development nance for previously-used landthan they were a few years ago but there are still a fewexceptions. Sources of grant aid should be identied andnegotiated as soon as possible after inception.

9. Tendering. Appointing contractors with experience ofsite remediation can be benecial as they may be able tosuggest ways of undertaking the work.

10. Construction. The site remediation/preparation worksmust be properly supervised and, most importantly,recorded, including sketches of where contaminantsor other site constraints, such as old services, werelocated.

11. Sales and marketing. This includes the community ofinformation to prospective purchasers and tenants. As tothe previous use of the site, contaminants found and themethods used to prepare the site for redevelopment. Anyattempt at concealment is likely to have adverse effectsonce it is discovered”.

22 Urban Design CompendiumLlewellyn-Davies for EnglishPartnerships and the HousingCorporation, 2000

The purpose of this compendium is to help equip projectapplicants, funding bodies and interested third partieswith guidance on achieving and assessing the quality ofurban design in developing and restoring urban areas. Itprovides a useful description of the optimum form of building(see below) with clearly illustrated examples as well asemphasising the need for efcient and inclusive approachto scheme development with mutually agreed and clearobjectives. It is intended that the compendium be used to



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guide policy development and for practical application in newdevelopment and regeneration so as to improve the qualityof housing-led regeneration projects and help with thepromotion of sustainable new development.

Key points include the following.

• The study makes a particularly salient point regardinghigh density:

“Some people continue to equate high densities withpoor urban quality such as overcrowding and reducedspace standards. This misses a fundamental point.Density is only a measure; it is a product of design nota determinant of it. The aim should therefore be not toachieve a residential density but to generate a criticalmass of people able to support urban services such aspublic transport, local shops and schools”.

• Regarding the optimum built form:

“In many urban situations, medium rise, high densitybuildings (of about 3-4 storeys) in general provide theoptimum form that maximises density whilst minimisingperceived intensity or overcrowding. They can also bedesigned to be attractive, energy efcient and mixed usewhilst:

• Reducing costs of land acquisition and siteinfrastructure;

• Avoiding costs of lifts and other services;

• Providing a robust form that allows for changes in useover time;

• Forming terraces or low rise ats, the most costeffective building form in housing;

• Increasing energy efciency and the ability to be orientedfor passive solar gain;

• Providing lifetime homes that can be readily adapted forthe elderly or disabled.

Thus well dened residential development can also providethe typical visual and environmental attributes of a suburbanestate – namely private entrances at ground level, adequategarden sizes, convenient car parking, signicant public space

and a pleasant aspect for windows. “In general, success is considered to emerge from:

• A widely based and consistent commitment from the



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communities involved, the landowners, developers,public authorities, funding agencies, voluntaryorganisations and the professional planning and designteam to a quality product;

• The establishment of an appropriate design managementand review process working at each stage of theproject, with a clear project management and reportingstructure;

• The assembly from the outset of a high quality multi-professional team working as a cohesive unit toward adened vision and agreed project objectives

23 Sustainable Residential Quality:Exploring the Housing Potential of LargeSitesLlewellyn-Davies in association withUrban Investment and MetropolitanTransport Research Unit, for the LondonPlanning Advisory Committee, 2000

This study focuses on the potential for development of largehousing sites in London and suggests density levels andappropriate built forms. It seeks to extend the applicationof the Sustainable Residential Quality approach, developedinitially in relation to small town centre sites, to large sitesacross London. Its main focus is on establishing a strategiccontext for exploring the housing potential of large sites inorder to extend Londoners’ housing choices and to secure ahigh standard of residential amenity.

In particular, it seeks to forge more effective linkagesbetween:

• Good quality urban design• Accessibility to public transport, local facilities and car

parking requirements; and• Housing capacity.

The publication has been overtaken by newer policydocuments but still provides a useful basis for the planningof large sites. It includes the Density Matrix for variouslocations and settings later used in the Draft London Plan.

Key points of the report are summarised below:

• Large sites are an important strategic resource,they have the potential to meet community needs for



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housing, employment and leisure, and can stimulatearea regeneration and support sustainable transportprovision.

• On suburban sites, net development densities of 250 HRH(c. 59 dwellings per hectare) can be achieved with mixof terraced, semi-detached and detached houses withgardens

• On suburban sites offering a mix of terraced, semi-

detached and detached houses with gardens as well asapartments with a mix of private and communal openspace, can increase densities to between 300 and 400HRH (c. 115 dwellings per hectare).

• On urban sites densities of up to 1,100 HRH can beachieved subject to high accessibility to public transportand facilities, a strong existing built context and a highquality of design

• A new policy approach to density is required to providefor net residential densities of between 150 and 1,100Habitable Rooms to the hectare when there is a highlevel of accessibility to public transport and facilities anda design sensitive to and areas established character canbe achieved.

• Arguments for and against the adoption of higherdensities for urban sites are often clouded bymisconceptions over the characteristics of the mainbuilding typologies available – the misconception thathigh-rise forms of development automatically meanhigher densities still exists

• Gross density considers the full site area, net densitygures only include access roads within the site, privategarden space, car parking area and incidental openspaces. The net density therefore excludes: majordistributor roads; schools; larger open spaces servicinga wider area; and landscape buffer strips

• Successful developments give consideration to new andexisting routes and desire lines; direct, secure attractiveand uninterrupted pedestrian and cycle routes; efcientand attractive public transport and a high quality streetenvironment that integrates the spatial needs of differingmodes of movement

• The most successful urban settings tend to becharacterised by patterns of mixed use, mixed tenure,

and mixed economy• A lack of or unsuccessful development partnerships are

often characterised by schemes conceived in isolation,schemes or developers that are unable or unwilling to



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modify designs, NIMBYism, and local authorities moreconcerned with political certainty:

“… the importance of integrated design teams andof creative partnerships between local authorities,developers and other stakeholders including thegeneral public, social housing providers, publictransport operators etc. Such partnerships havetended to underpin the most innovative and successfuldevelopments, but they are commonly absent from day today practice. All too often this is characterised by:

• A developer conceiving a scheme in isolation and thenseeking to push it through the statutory planning processas fast as possible and with the minimum possiblemodication;

• A local authority more concerned to control developmentso as to minimise the potential for local objections ratherthan to contribute positively to the development of thebest possible scheme;

• Key stakeholders such as public transport providers,being consulted on rm proposals rather than beingengaged in the initial design and development of thescheme; and

• The local community adopting a defensive attitude ratherthan recognising the potential for the development tomake a positive contribution to improving the quality ofthe local environment.”

24 But would you live there? Shapingattitudes to urban livingURBED, MORI and the School for PolicyStudies, University of Bristol, for theUrban Task Force, ODPM, 1999

This research was commissioned to help inform the UrbanTask Force’s consideration of how to make ‘the city a place ofchoice’ and to better understand how the public’s attitudes tourban living develop.

The publication explores attitudes to high density livingand reects on the perceptions that residents have ofthese matters. It concludes that a lack of shared languagefrustrates discussion about high-density living anddevelopment. It points out the importance of marketingmaterial in shaping opinions and perceptions. Key points areoutlined below.



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The study concludes that the housing market is fragmented,despite this the general population is anti-urban:

• “The general picture painted (by research on urbanattitudes) is one of a population that is anti-urban bothin the areas where it desires to live and in its choice ofhousing. This however is a mass market view…”

• “…other groups… are often dismissed as niche markets

but in reality they outnumber the young familiesgenerally regarded as the mass-market. Three in everyfour households are childless and more than half ofthese are below retirement age.”

• “The market for … urban housing has grown throughoutthe 1990’s while other parts of the new-build housingmarket have contracted. It is for this reason that housingmarket analysts have been urging developers for anumber of years to diversify away from suburban familyhousing to a higher value, urban product to cater for the80% of future households which are project to be singlepeople.”

• The perception exists that urban locations and theperceived excitement they offer are good to have close bybut not so close as to cause disturbance.

• Creating an image for a development needs a criticalmass of at least 100 units. An image can also be createdthrough contrasting a development with suburbandrabness and homogeneity, but care needs to be takenif promoting the excitement of urban living. Promotionalcampaigns need to be sophisticated.

25 Building the 21st Century Home: thesustainable urban neighbourhood Falk, N and Rudlin, D. ArchitecturalPress, Oxford, 1999

This publication asserts that current typical housing formscan, and will, become inappropriate for future generations.If the typical nineteenth century home was the urban terraceand the twentieth century home was the suburban semi,where will we be living in the twenty-rst century? Placesthat one generation regard as normal and even inevitablecan very quickly be seen as inappropriate for subsequent

generations with different needs. The study outlines how thismight be remedied while also reviewing past experiencesand thereby providing a useful historical context for theissues. Key points are below.



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• There is relatively little disagreement between localauthorities, developers, professionals and residentswhen new models of urban development are discussed ingeneral terms, but they disagree about the details:

“ When our ideas are discussed in general termswith local authorities, developers, professionals andresidents, there is relatively little disagreement. Butwhen the details are discussed private developers say itwill never sell, housing associations say it cannot be builtwithin cost limits, highway engineers complain that it isunsafe and planners argue that there will be conicts ofuse or town cramming.”

• The ethos of most professions and investors concernedwith the urban environment is largely anti-urban. Theextent to which they can create places that stand the testof time is therefore open to question:

“The planning system seeks to protect housing andother development from noise and trafc. Privacydistances, parking standards, building lines, fears ofover development, the zoning of uses, and landscapingrequirements all remain central to planning ideology.Road hierarchies (with limited access from distributorroads), parking requirements, turning heads, visibilitysplays, kerb radii and opposition to crossroads makeit impossible to create today many of the urbanenvironments that we so prize.”

• Less social housing is being built today than at any timein the last 100 years resulting in housing needs-basedallocation policies. Yet the standard of new housingis falling. Together these are creating the potentialfor a wide range of social problems. In new housingassociation estates there are sometimes more childrenthan adults and this ‘child density’ is closely correlatedwith a range of social problems

• If urban areas are to be revitalised it will be bytapping ideas of community rather than by importinginappropriate models from the suburbs.

• The UK house building industry tends to make its protsnot from building housing but from trading in land andthey have a strong incentive to keep it that way:

“.. the greatest value is attached to housing where greenbelt policy means that development sites are scarce.This has the effect of articially increasing land pricesso that, while we may not spend as much on housingconstruction as the Germans, we make up the differencein the price we pay for land. In 1945 land prices were 5%of the cost of housing. By 1960 this had risen to 40% and



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in parts of the South East today it is 65%. This meansthat the UK housebuilding industry makes most of itsprots not from building housing but from trading in landand they have a strong incentive to keep it that way. Giventhe importance of land to developers it is not surprisingthat they are reluctant to trade in the damaged productthat they consider most urban browneld land to be.”

“ Cutting corners on construction is a false economybecause it has only a minor impact on overall costs.As little as 30% of the cost of a new house is due toconstruction, compared to 35% for the land, 19.7% for thedeveloper’s overheads and 12.8% for infrastructure. Thereverse of course is also true; better specications neednot hugely increase total costs. This is where the realinuence on housing cost in the 21st century lies; noton what it will or will not allow us to build but rather onwhere and how we build housing”.

• If all current and projected (to 2016) vacant urban landwere developed for housing at garden city densities of30dph it would provide 1.6 million homes. At a more

urban density of, say, 62dph it would produce 3.4 millionhomes.

• Extra housing capacity is likely to come from:redevelopment of council estates and car parks; emptycommercial space; intensication of existing housing;better use of empty homes; space over shops andsubdivision of larger houses.

• The reduction of car use is seen by many commentatorsas the most profound inuence on future developmentforms.

• Urban green space therefore needs to be carefully

planned to maximise its contribution to the environmentwhile minimising its negative aspects. It is quality notquantity that counts.

• To its critics, density is synonymous with overcrowdingand town cramming. The limits of intensication must beunderstood for the city to be sustainable.

26 Possible Future Sources of LargeHousing Sites in London Halcrow Fox, for London PlanningAdvisory Committee, 1998

This report concludes that there are wide variety of reasonswhy sites are not brought forward for housing developmentincluding their potential value as an alternative use which



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may exceed that of residential development; because ofnational policy constraints; contamination constraints andownership constraints.

The report recommends that, to secure the development ofhousing sites, integrated policies and action will be required,clear policies or proposals identifying sites for housingare needed in UDP’s. positive advice on site development,infrastructure and environmental improvements should

be included in a development framework or planning brief.Minimum density policies are felt to be a blunt instrument.If they are to be used they should be based on a site by sitereview and applied exibly. On some, but not all, sites, anincrease in density may signicantly improve residentialviability. These increases or ‘density bonuses’ could be usedon contaminated sites to offset the costs of remediation.

Key points are as follows:

• Reasons for persistent site vacancy of the sites studiedincluded a lack of demand, physical constraintsincreasing development costs, owners decisions,institutional restrictions / difculties

• Constraints to residential development of large housingsites include access, site conditions, topography andsurrounding uses:

“Physical constraints such as access, site conditions,topography, and surrounding uses would be signicantbarriers to the development of some … sites. … Half ofthe most constrained sites were in transport or utilitiesuses. Many industrial, commercial and communityservices sites (were considered constrained) becausethey have substantial existing buildings. This need not

be a constraint provided that the residential value issufcient to meet demolition costs.”

• Contamination and uncertainty about the cost ofremediation and future liability is a barrier to thedevelopment of previously used sites

“Even where documentary or site investigation evidenceis available, land owners are reluctant to share theinformation. Remediation often cannot be accuratelycosted until full site investigations are complete.This uncertainty, compounded by concerns about thedevelopers;’ long term liability and house-buyers

concerns, can be a crucial deterrent to residentialdevelopers.”

• Land owners aspirations are critical to ensuring thesupply of housing land; owners will most like seek the



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most protable use, however they may take a long termview of what use will be most protable.

• There are wide reasons why sites are not broughtforward for housing development including their valuein alternative uses exceeds that under residentialdevelopment, because of national policy constraints,contamination constraining residential use, andownership constraints

• Securing the development of preferred housing sites canbe done through planning policies and briefs; site by sitereviews with appropriate minimum densities improvingresidential viability (or density bonuses) which can offsetthe cost of contamination; by offsetting lost open spacethrough contributions to the cost of new open space;by utilising land swap opportunities by direct action bypublic agencies by providing grants for contaminatedsites, differential development land taxes and other scalmeasures and by using CPO’s.

27 People in Cities: The Urban Environmentand its Effects Krupat. E. Environment and BehaviourSeries. Cambridge University Press,1985

This publication, although dated, provides a useful insightinto residents’ perceptions and attitudes into high densityliving. Key points include:

• High density living denitely has the capacity to bestressful. It creates problems of co-ordination among

people, it can reduce people’s ability to control theirenvironment and requires active coping

• People need a number of urban design elements toensure appropriate behavioural responses to the builtenvironment: security, legibility / clarity, privacy, theability to regulate social interaction, convenience andidentity

1. “…we can identify six needs common to all people thatcan be addressed by a behavioural approach to urbandesign:

2. Security. The need to feel safe and secure in the placewhere one lives is one of the most basic concerns of allurban dwellers. …

3. Clarity… the environment must be legible. People must



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feel condent about heir ability to nd their way fromone part of the city to another, or even from one part of alarge housing complex to another.

4. Privacy. People desire the ability to regulate the amountof contact hey have with others. …

5. Social interaction. …too much (privacy) in the form ofisolation, is at least as bad.

6. Convenience. …more a physical than social need ofpeople, yet it is also important. Urban environments atall levels should make the performance of day-to-dayand special tasks as easy as possible….

7. Identity. … the relationship of self to environment.”

• Resolving a gap between the needs of residents and theneeds met by an urban area requires involving users inplanning and design

• Residents need to have strong social networks, trusttheir neighbours, and believe in the effectiveness of thepolice – as well as themselves if they are to discouragecrime and intrusion in their neighbourhood. The bestarrangement of space alone will not deter crime



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7.0 USEFUL DEFINITIONSFROM THE LITERATUREREVIEW MATERIALNumbers relate to the publications reviewed.

11 High Density Housing in Europe:Lessons for London.PRP Architects for East ThamesHousing Group, 2002

What is high density?

Recent denitions of high density housing have comefollowing the publication of Planning Policy Guidance 3which states that new housing developments should aim fora density of 30 dwellings per hectare net, to avoid inefcient

use of land. This level of density is high relative to recent newbuild developments on greeneld sites. However this wouldbe considered low in the context of typical new build housingassociation developments in London. The draft LondonPlan indicates that densities between 30-150 dwellings perhectare can be achieved in areas outside central London(Policy 3A.16).

Examples of different levels of housing density are asfollows:

• Greeneld private development20 dwellings per hectare

• PPG3 private Greeneld development30 dwellings per hectare

• Typical Victorian street in Islington100 dwellings per hectare

• Typical inner London RSL development70 dwellings per hectare

• Typical street in Kensington and Chelsea (the mostdensely occupied part of England)

200 dwellings per hectareMeasuring Housing Density

In any detailed discussion of housing density different



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approaches to the measurement of it can be used, andtherefore we wish to clarify the approach used in this study.

The measure most commonly used by urban planners andplanning authorities in Britain assesses the physical spaceavailable for occupation per area of land. This is usuallyexpressed in dwellings per hectare (dw/ha or alternativelydw/acre) or habitable rooms per hectare (hr/ha or hr/acre).

However, measuring dwellings per hectare does notassess the occupancy of the dwellings created, and somecommentators argue that a truer measure of density musttake into account the number of people living on an area ofland, and the intensity of their use of it. This is more difcultto measure objectively, but can be illustrated by the followingmodels.

• Very intensive use

A recently built British social housing development,built by a housing association built to the maximumdensity permitted by the planning authority with 100%

nomination rights from the local authority. Typicallythis scheme will be fully occupied, with one personper bedspace – for example a two bedroom at wouldbe occupied by two adults and two children. Localauthorities often exercise their nomination rights byusing this accommodation for people on their homelesspersons list, many households of which will have noemployed members. The dwellings will therefore beoccupied for most of the day. As the development isrecently built, few residents will have grown up andmoved away. The development will therefore be veryintensively occupied, with high numbers of children andadults spending their time at home during the day, andthere will be greater use of common areas and openspace.

• Less intensive use

An established British social housing development, tenor fteen years old, built by a housing association built tothe maximum density permitted by the planning authorityoriginally with 100% nomination rights from the localauthority. Compared to the rst example, some of theoriginal children will have grown up and moved away,and more of the adults are in work, although some mayhave retired. More ats will be not be fully occupied, andtherefore the total number of residents is likely to beless.



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• Minimal use

A recent private development, built by a developer to themaximum density permitted by the planning authority.No social housing. Typically this will be occupied byhouseholds with one or more employed persons, anddwellings may be under occupied – for example a twobedroom at may be occupied by two working adults onlyand the second bedroom is used for guests or occasionalwork at home. More dwellings will be empty during theday as more residents will be working or undertakingactivities elsewhere.

12 Capital Gains: Making High DensityHousing Work in LondonCope, Helen with Avebury International,for the London Housing Federation,2002

Fig 3.2 Housing density measures

1. Dwellings or units per hectare or per acre – this refers tothe number of homes built upon a site.

2. Habitable rooms per hectare and per acre – this is themost common measure used in London. For example,a three-bedroom house with two double and one singlebedrooms, kitchen, living room and bathroom countsas having four habitable rooms. Small kitchens andbathrooms do not count. If, however, the house had adining kitchen, then it would have ve habitable rooms.

3. People or bedspaces per hectare or per acre – using theabove example, the three-bedroom house sleeps up to

ve people. This is what is meant by a bed space. Thuswe talk of a three-bedroom ve-person house as havingve bedspaces.

4. Potential child numbers per hectare or per acre– this denition of this term used in Capital Gainsis the number of children that can be housed on asite in accommodation of two bedrooms or over andassuming 50% single parent households ( a proportionrepresentative of inner London housing associationlettings). In the above example, the child potential ina three-bed, ve person house is four, allowing for asingle-parent. Across a scheme of 50 homes, however,only 25 homes are assumed to be headed by a singleparent rather than a couple.

5. Plot ratios – a plot ratio is not a measure of density. Itis the total area of the building, i.e. the footprint or oor



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19 Affordable Housing in London, SDSTechnical Report 1Three Dragons with the Centre forResidential Development, NottinghamTrent University, for the Greater LondonAuthority, 2001

• “The proposed affordable housing mix for the 50%affordable housing target is 35% social rent, 5%shared ownership and 10% key worker. For the 35%affordable housing target the mix is 25% social rent,3% shared ownership and 7% key worker. In practice,because payments to developers are based on HousingCorporation TCI’s, varying the mix of affordable housingdoes not have much impact on the residuals.

• “…a formula of calculating Payment in Lieu (of affordablehousing provision): PiL = X% of expected gross revenuefrom selling dwellings on a site with no affordable

housing. The value of X would vary by borough…Theexpected gross revenue could be agreed between thedeveloper and the borough on a site by site basis.”

• “Payments from RSL’s to developers for publicly fundedschemes are regulated by the TCI system which setsa maximum cost ceiling for a dwelling of a particularoor area and allows the RSL to deduct from this costceiling a standard proportion of oncosts to cover its ownadministrative requirements.”

22 Urban Design Compendium

Llewellyn-Davies for EnglishPartnerships and the HousingCorporation, 2000

The benets of seeking higher densities in overall termsinclude:

Social:

• Social proximity encourages positive interaction anddiversity;

• Improves viability of and access to community services;• Enables more and better integrated social housing




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Economic:

• Enhances economic viability of development;• Provides economies of infrastructure

Transport:

• Supports public transport;• Reduces car travel and parking demand

• Makes undercroft or basement parking economicallyviable

Environmental:

• Increases energy efciency;• Decreases resource consumption;• Creates less pollution;• Preserves and helps fund maintenance of public open

space• Reduces overall demand for development land.

25 Building the 21st Century Home: thesustainable urban neighbourhood. Falk, N and Rudlin, D, ArchitecturalPress, (1999).

Overcrowding – the number of people per room – hasconsistently been confused with density – the number ofdwellings or people per hectare. Overcrowding has beenlinked to ill health, poverty and crime and was one of themain targets of slum clearance. But high density areasneed not be overcrowded. Conversely it is possible to havea low density area in which overcrowding is a problem ifhouses are over occupied. The visionaries sought to reduceovercrowding but, with the exception of Le Corbusier,failed to recognise this point and their objective becamethe reduction of densities. A useful way to reconcile theseconfusions is to differentiate between density (an objective

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building for life - better neighbour hoods. making higher densities work - literature review

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