residential density - kerry county council · guidelines for planning authorities on residential...

Residential Density

Guidelines for Planning Authorities

BAILE ÁTHAARNA FHOILSIÚ AG OIFIG AN tSOLÁTHAIR.

Le ceannach díreach ónOIFIG DHÍOLTA FOILSEACHÁN RIALTAIS, TEACH SUN ALLIANCE,

SRÁID THEACH LAIGHEAN, BAILE ÁTHA CLIATH 2,nó tríd an bpost ó

FOILSEACHÁIN RIALTAIS, AN RANNÓG POST-TRÁCHTA,4-5 BÓTHAR FHEARCHAIR, BAILE ÁTHA CLIATH 2,(Teil: 01-6613111 - fo-líne. 4040/4045; Fax: 01-4752760)

nó trí aon díoltóir leabhar.

DUBLIN:PUBLISHED BY THE STATIONERY OFFICE.

To be purchased directly from theGOVERNMENT PUBLICATIONS SALE OFFICE, SUN ALLIANCE HOUSE,

MOLESWORTH STREET, DUBLIN 2,or by mail order from

GOVERNMENT PUBLICATIONS, POSTAL TRADE SECTION,4-5 HARCOURT ROAD, DUBLIN 2,

(Tel: 01-6613111 - ext. 4040/4045; Fax: 01-4752760)or through any bookseller.

Price: IR£2.00€2.54

ISBN 0-7076-6259-1

© Government of Ireland 1999

P. 65002 Gr. 30-01 2,500 9/99 Brunswick Press Ltd.

Guidelines for Planning Authorities on Residential Density

Contents

1.0 Context 5

2.0 Measuring Densities 82.1 The Role of Density 82.2 Gross and Net Densities 82.3 Methods of Controlling Residential Density 9

3.0 Appropriate Locations for Increased Densities 103.1 Town and City Centres 103.2 ‘Brownfield’ Sites 103.3 Inner Suburban/Infill 103.4 Outer Suburban/‘Greenfield’ Sites 113.5 Institutional Lands 123.6 Town/Village 12

4.0 Residential Density and the Development Plan 134.1 Policies 134.2 Local or Action Area Plans 13

5.0 Controls and Safeguards 155.1 The General Approach 155.2 Plot Ratio 165.3 Site Coverage 165.4 Building Line 175.5 Building Height 175.6 Overlooking/Overshadowing 185.7 Public Open Space 185.8 Private Open Space 205.9 Car Parking and Road Standards 215.10 Internal Space Standards 235.11 Ecology and Bio-diversity 23

6.0 ‘Taking in charge’ and Management of Residential Estates 24

Appendix 1 List of Relevant Publications 25

Appendix 2 Glossary of Terms 26

3


1.0 Context

1.1 The Department of the Environment and Local Government issued Circular Letter PD4/98 in May 1998 to advise planning authorities in relation to promoting increaseddensities in appropriate locations, the safeguards required and the steps that should betaken. The Circular stated the Department’s intention to publish Planning Guidelines inrelation to residential densities. Following a request for proposals, Fergal MacCabe,Architect and Town Planner, in association with McCrossan O’Rourke, Architects andJones Lang Wootton, Chartered Surveyors was appointed to undertake a study andprepare draft Guidelines for planning authorities. The Study* and the draft Guidelineswere prepared under the guidance of a small Steering Committee. The draft Guidelineswere circulated widely for comment. This final version of the Guidelines has had regardto the observations received by the Department during the public consultation process.These Guidelines replace the guidance in relation to residential densities in theDepartment’s Circular of May 1998. The Guidelines set out policies and standards but arenot intended as a design guide. The Guidelines are addressed to all planning authorities.

1.2 The hitherto relatively cheap cost of land in Ireland and rising car ownership has resultedin extensive suburban development at densities which are relatively low by Europeanstandards. A high proportion of new suburban housing has been provided in a detachedor semi-detached form. Meanwhile the decline in the residential populations of town andcity centres, which had persisted for so many years, is being redressed, albeit principallyin the form of multi-storey apartments. Today, increasing traffic congestion and the urgentdemand for new homes are pressing problems which require the reappraisal of somepolicies and the strengthening of others, particularly in the light of three emergingsignificant social, economic and environmental considerations, namely: -

1.2.1 SustainabilityNational Strategy as outlined in the document “Sustainable Development - A Strategy forIreland (DoELG 1997)” sets out the Government policy of encouraging more sustainableurban development by the avoidance of excessive suburbanisation and the promotion ofhigher residential densities in appropriate locations in harmony with improved publictransport systems. Ireland’s legally binding commitment under the Kyoto Protocol alsocommits the Government to reduce emissions of a basket of greenhouse gases to 13%above 1990 levels in the period 2008-2012. Without intervention, emissions of thesegases are projected to increase by approximately 28%. In order to meet the nationaltarget, the Government is taking significant action in all sectors, including the residentialand transport sectors, to reduce energy consumption and to support a more efficient useof energy. More sustainable building types which optimise energy performance andreduce CO2 emissions, use renewable materials and efficient components and fittings andare designed flexibly to facilitate adaptation to changing uses are required. Themaintenance, refurbishment and re-use of the existing building stock and infrastructurewill also promote sustainability and reduce the need for ‘greenfield’ development.

1.2.2 DemographyHousehold sizes in Ireland have fallen from a level of 3.54 persons per household in 1986to 3.14 in 1996 and are set to fall to 2.6 persons by 2011, whilst population growth is

5

* “Planning Issues Relating to Residential Density in Urban and Suburban Locations” - MacCabe, McCrossan O’Rourke, JonesLang Wootton (1999)


expected to continue and to reach a figure of 4.4 million persons by the year 2026. Suchchange, coupled with economic prosperity, will have significant implications for the scaleand type of future housing stock. The trend towards more single person households isevident across Europe and is being replicated in Ireland. A more varied range of dwellingtype and size than has been provided heretofore will be necessary.

1.2.3 AffordabilityThe Government’s concern at the rise of house prices has been clearly indicated in thecommissioning of the Report on the Study of House Prices (the Bacon Report) and in theactions taken arising from its findings - including commissioning the preparation of theseGuidelines. Despite an increase in housing completions from 21,000 in 1993 to over42,000 in 1998, housing demand still remains high relative to supply. The presentdifficulties experienced by first time buyers, particularly in the Dublin area, can beaddressed by the provision of more dwellings. The use of zoned and serviced residentialland to its maximum will assist in achieving this objective as will the provision of agreater proportion of dwellings more suitable to changing and smaller household sizes.More compact, innovative types, such as terraced or single aspect houses, may result incheaper construction costs also.

1.3 General Policy1.3.1 The Department’s Circular Letter of May 1998 set out, from a planning perspective, the

benefits of increased residential density as including:

◆ more economic use of existing infrastructure and serviced land,

◆ a reduced need for the development of ‘greenfield’ sites, urban sprawl and ribbondevelopment,

◆ reduced need for investment in new infrastructure,

◆ better access to existing services and facilities, and

◆ more sustainable commuting patterns.

1.3.2 Where strategic planning guidelines are being undertaken at a regional level, residentialdensities should also be addressed. Such strategies should address broad population anddensity patterns and references to dwelling mix would also be appropriate.

1.3.3 There is a need for a complementary approach adopted by adjacent planning authoritiesin the matter of residential densities in order to avoid conflicting policies on either side ofadministrative boundaries.

1.3.4 Planning authorities should vary their Development Plans, where necessary, to give effectto the recommendations and policies contained in these Guidelines. In general,Development Plans should give specific recognition to the importance of achieving higherresidential density in appropriate areas such as ‘brownfield’ sites, sites in proximity totown centres or public transport corridors in the interest of providing a more sustainableresidential pattern. Planning authorities should also review their policies in relation todensities permitted in ‘greenfield’ developments.

1.3.5 Planning authorities should, in the exercise of their development control functions,promote increased residential density, where appropriate to do so in the context of theirexisting Development Plan and having regard to these Guidelines and the principles ofproper planning and development. Planning authorities will be aware, however, that

6


7

higher residential density will not be appropriate in every circumstance. Higher densitiesmust not be achieved at an unacceptable amenity cost to the surrounding dwellings andthe residents of the proposed development. A high quality of design and layout and agood quality living environment, including the availability of adequate shopping, social,transport and leisure infrastructure, are essential if increased residential densities are to beacceptable.

1.3.6 Planning authorities should consider the preparation and implementation of Local orAction Area Plans for areas that are to open up for significant residential development andwhich could reduce the amount of land needed to accommodate a given number ofdwellings by means of well thought out provision of open space, efficient road layoutsand pooling the provision of facilities.

1.3.7 Planning authorities have a duty under the Local Government Act, 1991, in theperformance of their functions under any enactment, to have regard to policies andobjectives of the Government or any Minister, insofar as they may affect or relate to theirfunctions. National policies on sustainable development and on residential density arepolicies to which regard should be had in the exercise of planning functions.


2.0 Measuring Densities

2.1 The Role of DensityDensity assumptions play an important part in estimating the development landrequirements arising from a new dwelling requirement/forecast. Indeed without anassumption about how many “units” can be accommodated in a given area, it would beimpossible to move from forecast demand to an estimate of how much land will beneeded.

While the principle of the approach is straightforward - a site area multiplied by a densityassumption to produce an estimate of site capacity - the practical application is more complicated and is dependent in particular on the appropriate definitions of site/development areas, as well as to a lesser extent, on using the correct densitymeasure.

Selecting the appropriate definition of site/development area is important. Where non-residential uses, such as main roads, retail, employment and major open spaces are beingplanned in conjunction with housing, an allowance needs to be made in the densityassumption for the land that will be occupied by these non-residential uses which may beupwards of 25% at the neighbourhood or district scale.

At the site-specific level, if density controls are to produce the expected results, a densitystandard must be carefully related to the area accommodating the development.

At different stages in the planning of a new development area, standards andmeasurement can be refined from an overall density which embraces the full range ofurban uses down to one which includes only the residential component of an individualsite. As the focus narrows and the area becomes smaller, the residential densityassumption in terms of the number of dwellings per hectare will rise.

2.2 Gross and Net DensitiesA ‘Gross’ density measure is best applied to estimating land areas required for mixed usedevelopments or where a neighbourhood master plan is being prepared, involving anumber of neighbouring sites which have not been accurately defined.

A net site density measure is a more refined estimate than a gross site density measureand includes only those areas which will be developed for housing and directly associateduses.

This will include:

◆ Access roads within the site

◆ Private garden space

◆ Car parking areas

◆ Incidental open space and landscaping, and

◆ Children’s play areas where these are to be provided.

8


9

It therefore excludes:

◆ Major and local distributor roads

◆ Primary schools, churches, local shopping etc.

◆ Open spaces serving a wider area, and

◆ Significant landscape buffer strips.

A net density is the most commonly used approach in allocating housing land in Local orAction Area Plans and is appropriate for development on infill sites where the boundariesof the site are clearly defined and where only residential uses are proposed. It is alsoappropriate where phased development is taking place in a major development area(perhaps spanning different plan periods) and individual housing areas have beenidentified.

2.3 Methods of Controlling Residential Density2.3.1 An analysis of international practice indicates that in general, the methods for controlling

density fall into two principal categories: -

◆ Dwellings per hectare Most common in the UK and Ireland

◆ Plot Ratio (i.e. total amount Most common in other European countries, of floorspace over total site area) such as Belgium, France, Germany, Italy,

Sweden and also USA

To a lesser extent, habitable rooms or bed spaces per hectare are used but are notwidespread.

2.3.2 Research carried out by the Department of the Environment, Transport and the Regions inthe UK and an examination of case studies in Ireland indicate that of the various methodsemployed for measuring density, dwellings per hectare is the most appropriate measurefor estimating development land requirements, making housing land allocations,monitoring completions/take up and in providing a broad indication of the intensity/formof development envisaged on a site or area. However, dwellings per hectare is not effectivein predicting or controlling the form of development on a site - planning standards orplot ratio are more effective. In large measure the lack of predictability and consistency ofthe other methods results from the fact that average size of dwellings and average area perhabitable room can vary substantially (i.e. terraced townhouses versus large familyhouses).

2.3.3 Dwellings per hectare is the most appropriate measure for estimating the gross or netyield of existing or future housing, but should be used in conjunction with otherplanning standards and with plot ratio in particular when controlling development form(see paragraph 5.2).


3.0 Appropriate Locations for IncreasedDensities

In general, increased densities should be encouraged on serviced land or land proposedto be serviced and particularly in the following locations: -

3.1 Town and City CentresThe increase of population within city or town centres with their range of employment,recreation, educational, commercial and retail uses will curtail travel demand andtherefore these locations have the greatest potential for the creation of sustainable patternsof development. Such increased populations will assist in urban regeneration, make moreintensive use of existing infrastructure, support local services and employment, encourageaffordable housing provision and sustain alternative modes of travel, such as walking,cycling and public transport. The infilling of “gap” sites will also contribute to theimprovement of the architectural form.

In order to maximise inner town and city population growth, there should, in principle,be no upper limit on the number of dwellings that may be provided within any town orcity centre site, subject to the following safeguards: -

◆ Compliance with the policies and standards of public and private open spaceadopted by Development Plans (see paragraphs 5.7 and 5.8);

◆ Avoidance of undue adverse impact on the amenities of existing or future adjoiningneighbours (see paragraph 5.6);

◆ Good internal space standards of development (see paragraph 5.10);

◆ Conformity with any vision of the urban form of the town or city as expressed inDevelopment Plans, particularly in relation to height or massing;

◆ Recognition of the desirability of preserving listed or protected buildings and theirsettings and of preserving or enhancing the character or appearance of aConservation Area;

◆ Compliance with plot ratio and site coverage standards adopted in DevelopmentPlans (see paragraphs 5.2 and 5.3).

3.2 ‘Brownfield’ Sites‘Brownfield’ lands which may be defined as “any land which has been subjected to building,engineering or other operations, excluding temporary uses or urban green spaces” generallycomprise redundant industrial lands or docks but may also include former barracks,hospitals or even occasionally obsolete housing areas. Where such significant sites existand, in particular, are proximate to existing or future public transport corridors, theopportunity for their re-development to higher densities, subject to the safeguardsexpressed at paragraph 3.1 above or in accordance with Local or Action Area Plans,should be promoted.

3.3 Inner Suburban/InfillThe provision of additional dwellings within inner suburban areas of towns or cities,proximate to existing or due to be improved public transport corridors has the potential

10


for revitalising areas by utilising the capacity of existing social and physical infrastructure.Such development can be provided either by infill or by sub-division.

3.3.1 Infill Residential DevelopmentPotential sites may range from small gap infill, unused or derelict land and backlandareas, up to larger residual sites or sites assembled from a multiplicity of ownerships. Inresidential areas whose character is established by their density or architectural form, abalance has to be struck between the reasonable protection of the amenities and privacyof adjoining dwellings, the protection of established character and the need to provideresidential infill. The design approach should be based on a recognition of the need toprotect the amenities of directly adjoining neighbours and the general character of thearea and its amenities, i.e. views, architectural quality, civic design etc. However, subjectto reasonable conformity with these, developments on infill sites, particularly those inexcess of 0.5 hectares (1.2 acres), should be capable of proposing their own density andcharacter. Local authority intervention may be needed to facilitate this type ofdevelopment, in particular with regard to the provision of access to backlands.

3.3.2 Sub-division of DwellingsMany inner suburbs contain large houses on relatively extensive sites whose conversion tomultiple dwellings without a dramatic alteration in the public character of the area isachievable. In such areas, particularly those of falling population but which are wellserved by public transport, their conversion to multiple occupancy should be promotedsubject to safeguards regarding internal space standards, private open space andmaintenance of the public character of the area. Standards of off-street car parking mightbe relaxed to encourage the occupation of the dwellings by households owning fewercars. Special care will be required to protect the integrity of these buildings where theyare listed for preservation or protection.

In newer areas, particularly those consisting solely of semi-detached houses, which areproximate to existing or improved public transport corridors, planning authorities shouldconsider policies which would permit more intense residential usage, subject to designsafeguards e.g. end houses with more extensive plots and a capacity for limited extensionmight be appropriate for conversion to multiple dwellings.

3.4 Outer Suburban/‘Greenfield’ SitesThese may be defined as open lands on the periphery of cities or towns whosedevelopment will require the provision of new infrastructure, roads, sewers and ancillarysocial and commercial facilities, schools, shops, employment and community facilities.Such lands would probably represent most of the large scale accretions to our urban areasof the past 20 years and have been developed at net densities of between 15 to 20dwellings per hectare (6-8 dwellings per acre) in a detached or semi-detached form.

Studies have indicated that whilst the land take of the ancillary facilities remains relativelyconstant, the greatest efficiency in land usage on such lands will be achieved by providingnet residential densities in the general range of 35-50 dwellings per hectare (14 - 20 peracre) and such densities should be encouraged generally.

Development at densities less than 20 dwellings per hectare (8 per acre) should generallybe discouraged in the interests of land efficiency, particularly on sites in excess of 0.5hectares. On lands proximate to existing or proposed public transport corridors, densities

11


12

in excess of 50 dwellings per hectare (20 dwellings per acre) should be permitted, subjectto appropriate qualitative safeguards.

Where ‘greenfield’ lands are to be served by existing or improved public transportcorridors, planning authorities should consider the preparation of Local or Action AreaPlans for such expanded areas, setting targets for increased density yields.In exceptional cases, where for reasons of proximity to an environmental or ecologicallysensitive area or where there is a need to make an appropriate transition between higherdensity development and the open countryside, planning authorities might consideridentifying very limited areas of lower density development in their Development Plans.

3.5 Institutional LandsA considerable amount of developable land in suburban locations is in institutional use.Such lands are often characterised by large buildings set in substantial open lands whichin some cases, may offer a necessary recreational or amenity open space opportunityrequired by the wider community. In the event that planning authorities permit thedevelopment of such lands for residential purposes, then it should be an objective toretain some of the open character of the lands, but this should be assessed in the contextof the quality and provision of existing or proposed open space in the area generally. Inthe development of such lands, densities at least in the range suggested at 3.4 aboveshould prevail and the objective of retaining the open character of the lands achieved byconcentrating increased densities in selected parts. The preparation of Local or ActionArea Plans setting out targets for density yields, recreational uses and urban form shouldbe considered in advance of development.

3.6 Town/Village3.6.1 In the case of residential development on serviced lands in towns or villages located in

existing or planned quality public transport corridors, particularly those which have sparecapacity in existing facilities such as schools, shops, libraries, health centres, childcarefacilities etc., increased densities would be appropriate in order to maximise such socialand infrastructural investment.

3.6.2 On serviced lands in towns or villages not served by quality public transport, increaseddensities would be acceptable if they contributed to the enhancement of town or villageform such as by reinforcing street patterns or assisting in the re-development ofbacklands. Special care will be required to protect the architectural and environmentalquality of villages of special character.

3.6.3 On serviced lands in villages, proposals for developments with densities of less than 20dwellings per hectare (8 per acre) might be considered in limited circumstances in orderto act as an alternative to the provision of one-off rural housing.


4.0 Residential Density and theDevelopment Plan

4.1 PoliciesThe most effective use should be made of zoned and serviced lands by the avoidance ofinefficient low density development in order to prevent urban sprawl and promoteefficiency in the use of energy, transport and natural resources. In particular, thelocational advantages of serviced lands proximate to existing or planned public transportcorridors should be maximised. New residential development should recognise emergingdemographic trends and by its design and layout, provide a high quality and attractiveenvironment.

Planning authorities should review and vary if necessary their Development Plans topromote higher residential densities, particularly in re-developing ‘brownfield’ sites and inproximity to town centres and public transport corridors. This may require thepreparation of capacity studies to identify the potential for providing additional housing.Where such potential exists but is impeded, actions necessary to achieve the release of theland whether by provision of access, services, site assemblage or otherwise, should beundertaken.

Other Development Plan policies which might inhibit the provision of increased densitiessuch as: -

◆ The need to take cognisance of prevailing adjacent densities or the maintenance ofestablished character,

◆ Off-street parking standards and access and carriageway standards,

◆ Height restrictions,

should be reviewed and if considered necessary, appropriately revised.

Planning authorities should take a proactive approach to identifying specific areas whereincreased densities would be appropriate, e.g. in the vicinity of railway stations or othertransport interchanges and through Local or Action Area Plans, identifying their potentialyield, dwelling mix and form. Such Local or Action Area Plans might propose a range ofdensities and indicate minimum densities, if considered appropriate.

As part of an overall policy to achieve the more integrated and sustainable developmentof all residentially zoned lands, higher densities should be promoted. Firm emphasismust be placed by planning authorities however, on the importance of qualitativestandards in relation to design and layout in order to ensure that the highest qualityof residential environment is achieved. Pre-planning discussions with developerswould be helpful in achieving a quality environment. The objective should be theachievement of an efficient use of land appropriate to its context, while avoiding theproblems of over-development.

4.2 Local or Action Area PlansLocal or Action Area Plans should play an important role in setting the framework for theachievement of integrated and balanced communities in development areas, providing forschools, social and recreational facilities, local shopping and appropriate employment

13


14

uses, integrated with housing, roads and the public transport network. Appropriate grossand net density targets should be identified when Local or Action Area Plans are beingprepared. The Plans should state net densities (see paragraph 2.2 above) and shouldfacilitate increased density. The Plans should be based generally on the provision ofindividual neighbourhood units, within which environmental traffic cells will formidentifiable phases of development. Each cell should have limited access points from localdistributor or main roads.

Each residential scheme within a Local or Action Area should be designed to: -

◆ Make a positive contribution to its locality and take best advantage of its location bythe use of site topography, i.e. levels, views, landscape and design orientation, i.e.sunlight and daylight, to optimise sustainability

◆ Have a sense of identity and place and legible spatial hierarchy associated with theplaces within and the routes through the scheme

◆ Have a public area design which is guided by the best principles of passivesurveillance to encourage a safe sense of place and discourage anti-social behaviour

◆ Be characterised by an easily legible design approach to the grading from public toprivate areas.


5.0 CONTROLS AND SAFEGUARDS

5.1 The General Approach

Criteria for Higher DensitiesThe following criteria should be taken into account when assessing applicationsincorporating higher densities: -

◆ Size of Site Generally higher densities should be considered in respect of all sites but will beparticularly appropriate for sites in excess of 0.5 hectares (approximately 1.23 acres).

◆ Proximity to town/city centre facilities and to existing or planned qualitypublic transport corridors.Such locations should be appropriate for the provision of higher densities.

◆ Quality of Proposed Layout and Elevational DesignThe quality of the residential environment should be paramount in the acceptabilityof planning applications for higher density schemes. Layouts should take account ofenergy demand. As many dwellings as possible should have access to sunlight.

◆ Mix of Dwelling TypesAll schemes on sites in excess of 1.0 hectares (approximately 2.47 acres) should berequired to have a variety of dwelling types.

◆ Ancillary FacilitiesThe provision of an appropriate scaled range of social and community facilities,including shopping, education, health and childcare.

◆ Quality of Proposed Open Space and General Landscaping.Detailed landscape proposals, including specifications, should be submitted with allplanning applications. The detail of these proposals should form an integral part ofthe assessment of the quality of the proposed layout.

◆ Quality of Pedestrian Linkages between Open Spaces and to and from LocalFacilities.The provision of safe pedestrian and cycle links to enable safe access as far aspossible to open spaces and local facilities should be required. Narrow, potentiallyunfrequented or unsupervised routes should not be permitted.

◆ Levels of Privacy and AmenityPrivacy is an essential part of the quality of the residential environment. Therelationship of buildings to one another, potential overlooking, sunlight/daylightstandards and the use of screening devices and landscape elements should form thebasis of assessment.

◆ Traffic SafetyThe quality of the layout and the manner in which it addresses traffic safety is vital.Long straight roads should be discouraged and a layout with good provision forpedestrian safety should be preferred. Proposals for traffic calming should form partof the layout proposals at planning application stage.

15


◆ Local or Action Area PlansCompliance with the objectives and requirements of Local or Action Area Planswhere appropriate, e.g. access to local facilities or public open space.

◆ Children and the ElderlyThe needs of children, the elderly and the disabled, especially their safety, shouldalso be taken into account.

The overriding concern should be the quality of the proposed residential environmentand higher densities should only be acceptable if all of the criteria which contribute tothis environment are satisfied. In this regard, planning authorities should consider thepreparation of Design Guides illustrating good examples of residential layouts at increaseddensities, appropriate to local circumstances.

5.2 Plot RatioPlot ratio expresses the total amount of floor space in relation (proportionally) to the sitearea. The following range of indicative plot ratios is recommended: -

◆ City/Town Centre/‘Brownfield’ - plot ratio 1.0 - 2.5.

◆ Inner Suburban - plot ratio 0.5 - 1.0

◆ Outer Suburban◆ In close proximity to public transport - plot ratio 0.35-0.5◆ Remote from public transport - plot ratio 0.25-0.35

These indicative plot ratios should provide a mix of dwelling sizes in each case and thenumber of dwellings per hectare may vary significantly depending on the mix.

Plot ratios need to be used in conjunction with effective planning standards. They candetermine the maximum building floor space area or volume on a given site area, but ontheir own cannot define built form. The same area or volume can be distributed on a sitein different ways to generate very different environments. This can range from larger sitecoverage of low bungalows or patio houses, through to high rise tower blocks.

Other factors, therefore, have to be applied alongside plot ratios in order to give a morequalitative definition to the built form.These include: -

◆ Height

◆ Public open space provision

◆ Private open space provision

◆ The standards applied to estate roads, off-street car parking provision.

5.3 Site CoverageSite coverage is a control for the purposes of preventing the adverse affects of over-development and thus safeguarding sunlight and daylight within or adjoining proposedlayouts or buildings.

The site coverage index is determined by dividing the total area of ground covered bybuildings by the total ground area within the curtilage of the buildings, excluding anyland lying between the building line and the public street.

16


Site coverage is probably only directly relevant in inner urban locations, where openspace and car parking may not be contributing factors and where indicative site coveragelayout controls are required to ensure that over-development is avoided. In such cases, arange of between 70% to 80% is considered appropriate.

5.4 Building LineMany Development Plans include a requirement of a minimum setback from the publicfootpath of approximately 7.5 metres in order to allow adequate space for on-curtilage carparking in front gardens. In the context of a more innovative layout, incorporating groupedcar parking or parking courts etc., it may be necessary to adopt a more flexible attitude tothis standard. The desirability of creating different urban forms will require a more variedbuilding line in order to reduce the often regimented appearance of suburban layouts.Flexibility, therefore, should be incorporated as an objective in Development Plans to allowvariation in building lines, provided that there is an overall coherence to the design andsome provision, where appropriate, for a privacy zone to the front of each dwelling.

5.5 Building HeightOne of the common perceptions in relation to higher densities is that they promote tallerbuildings. As case studies have shown, it is possible, however, to increase densitysignificantly with modest increases in height.

In general, low rise buildings which respect the scale and character of Irish towns andcities are appropriate, save for particular cases such as those outlined below.

Higher buildings, i.e. those which are significantly higher than neighbouring orsurrounding development, incorporating increased densities may be appropriate: -

◆ In locations specifically identified in Development Plans as being appropriate forhigher buildings

◆ In locations close to an expanse of water or public parkland where a building ofgreater scale is more appropriate or in a central district, town or city centre locationwhere an increase in massing and height in the form of a contemporary and stylishbuilding, could make a positive contribution to the skyline.

Where buildings of significant height are proposed, however, it is important that thefollowing factors will be taken into consideration:

◆ The quality of the overall design

◆ The degree of overshadowing and consequent loss of light caused to surroundingproperty

◆ The degree of overlooking (particularly of residential property) and consequent lossof privacy

◆ The extent to which there is a disruption to the scale of an existing streetscape orlandscape, save in cases where this may be intended for civic design reasons

◆ The extent to which the building detracts from structures or spaces of architecturalor historic importance or important landmarks

◆ Any attractive views from significant vantage points that would be obscured orintruded upon by the building

17


◆ The degree of obtrusion of the skyline, save for those in appropriately plannedlocations

◆ The scale of the building in relation to surrounding open space, together with theeffect of the building on the quality of the space

◆ The avoidance of local, undesirable micro-climates at ground level.

5.6 Overlooking/OvershadowingIt is an important quality of the residential environment that the private spaces of everydwelling should enjoy freedom from undue observation by others and that no undue lossof light is caused by overshadowing from adjoining higher buildings. This applies to alldwellings, whether they are located in proposed new developments or adjoining newresidential schemes. An individual has a right to expect freedom from undue observationor overshadowing in any new development.

5.6.1 Overlooking In general, the 22.0 metres distance between opposing first floor windows is an acceptednorm in residential design. However, with the evolution of more innovative residentiallayouts and the incorporation of a wider variety of dwelling types, standards regardingoverlooking may have to be looked at more carefully. Overlooking is a function of a desireto create privacy but it does not necessarily follow that, for example, all opposing windowsneed to be 22 metres apart. Windows serving halls and landings do not require the samedegree of privacy as say balconies and living rooms. Innovative dwelling types which takeaccount of these factors such as single aspect houses which have their main sleeping andliving areas on one side and circulation and bathrooms etc. on the other, can provideadequate levels of privacy without incorporating 22 metres distances in all cases. Thosehousing forms can create a more attractive village atmosphere to new developments andmove away from the often sterile pattern of traditional suburban layout.

In short, flexibility must be employed in the assessment of the overlooking aspects in newresidential design. However designers will need to be cautious to ensure that thisflexibility is not abused. For example, where new schemes are proposed in existingresidential areas, the use of living rooms and balconies on upper floors can causesignificant loss of amenity to adjoining dwellings if they are located close to theboundaries. A separation of 35 metres or greater or modified design should be consideredin the case of overlooking living room windows and balconies.

5.6.2 OvershadowingOvershadowing will generally only cause problems where buildings of significant heightare involved or where new buildings are located very close to adjoining buildings.Planning authorities should require that daylight and shadow projection diagrams besubmitted in all such proposals. The recommendations of “Site Layout Planning forDaylight and Sunlight: A Guide to Good Practice” (B.R.E. 1991) or B.S. 8206 “Lighting forBuildings, Part 2 1992: Code of Practice for Daylighting” should be followed in this regard.

5.7 Public Open Space5.7.1 Introduction

Public open space is one of the key elements in defining the quality of the residentialenvironment. It provides passive as well as active amenity and has important ecologicaland environmental aspects.

18


5.7.2 Current PracticeIn general, planning authorities in Ireland set out detailed quantitative standards in theirDevelopment Plans. Less emphasis is placed on qualitative standards. This can give rise toresidential estates having adequate amounts of open space but very often poorly locatedor unsuitably shaped. This results in underused spaces and in some cases spaces whichencourage anti-social activity.

The achievement of higher densities must be coupled with a higher standard of residentialenvironment and thus the provision of higher quality public and communal open spaces isof paramount importance. Any acceptance of lower quantitative standards of open spacemust be accompanied by a parallel increase in qualitative standards of open space.

5.7.3 Recommended Qualitative Standards

Design of Open Space Much greater emphasis should be placed on the quality of open space to be provided anddetails of the proposed landscaping hard and soft, of these spaces should be providedwith planning applications.

◆ The objective should be to seek well designed open space visually as well asfunctionally accessible to the maximum number of dwellings within the residentialarea.

◆ Planning authorities should not permit the provision of open space where it isinadequately overlooked, supervised or accessible.

◆ Emphasis should be placed on the need to retain existing natural features (e.g. animportant stand of mature trees or stream) and to provide open space in its vicinityto ensure its visual setting and protection.

◆ Open spaces should be suitably proportioned and narrow tracts, which are difficultto manage, should not be acceptable.

◆ In new development areas, Local or Action Area Plans should identify at an earlystage the preferred location of larger open spaces including, if considered appropriate,locations in the non development areas adjoining the development areas. This mayallow playing pitches and larger recreational facilities to be concentrated away fromhousing areas but easily accessible from them and allow a more flexible approach toopen space requirements within residential estates by way of more casual spacessuitable for smaller children’s play, informal kickabout and passive amenity. Thecriteria used for selection of preferred locations should include preservation of naturallandscaping features, accessibility and gradient. Suitable pedestrian linkage betweenopen spaces should be identified and where appropriate cycle lanes provided.

◆ The use of hard landscaping elements such as paving, cobbled areas etc. should playan increasingly important role in the design and presentation of open spaceconcepts. Hard play areas such as all-weather surfaces should also be taken intoaccount when assessing new proposals.

5.7.4 Recommended Quantitative StandardsThe provision of open space to serve new residential developments should be on ahierarchical basis varying in size from large regional parks to small children’s play areaand passive recreation spaces close to peoples’ homes.

Most planning authorities include quantitative standards for public open space in theirDevelopment Plans. These are represented either as a requirement per person or as a

19


percentage of site area. Most common amongst the requirements are 15/20 m2 per personor 10-14% of site area.

Assessing open space requirements on a population basis can be difficult due to theunpredictability of occupancy rates where often larger houses and apartments areoccupied by fewer persons than the number of bed spaces would indicate. Case studiesalso indicate that where existing recreational facilities are available close to town and citycentres, public open space provision on a strictly population basis is not appropriate.Apartment developments in particular, located in the inner city where bed space rates arenormally high, will be unable to achieve public open space standards similar to suburbandevelopments where bed space rates are considerably lower.

In essence, it will be necessary for planning authorities to take a more flexible approach toquantitative open space standards and put greater emphasis on the qualitative standardsoutlined above. Where residential developments are close to the facilities of city and towncentres or in proximity to public parks or coastal and other natural amenities, a relaxationof standards should be considered. Alternatively, planning authorities may seek a financialcontribution towards public open space or recreational facilities in the wider area in lieu ofpublic open space within the development. However, to ensure that there are adequatesafeguards in place to avoid over-development and to assist the planning authority in theirassessment of planning applications, in general the following standards are recommended:-

In greenfield sites or those sites for which a Local or Action Plan is appropriate, publicopen space should be provided at a minimum rate of 15% of the total site area. Thisallocation should be in the form of useful open spaces within residential developmentsand, where appropriate, larger neighbourhood parks to serve the wider community.

In all other cases, public open space should be provided at a minimum rate of 10% of thetotal site area.

5.7.5 Public Open Space on Institutional LandsInstitutional lands and ‘windfall’ sites are often characterised by a large private orinstitutional building set in substantial open lands which in some cases may be accessibleas an amenity to the wider community. Any proposals for higher density residentialdevelopment must take into account the objective of retaining the “open character” ofthese lands while at the same time ensuring that an efficient use is made of the land. Inthese cases a minimum requirement of: -

◆ Compliance with the standards set out above or

◆ 20% of site area

whichever is greater, should be specified; however, this should be assessed in the contextof the quality and provision of existing or proposed open space in the wider area. Whilstthe quantum of open space may be increased vis-à-vis other sites, the amount ofresidential yield should be no less than would be achieved on any comparable residentialsite. Increasing densities in selected parts of the site subject to the safeguards expressedelsewhere may be necessary to achieve this.

5.8 Private Open Space

5.8.1 IntroductionPrivacy is an essential part of the quality of a residential environment. The provision of anadequate sized external space, which is free from undue observation, is a fundamentaltenet of residential amenity. Privacy can be achieved in a wide variety of ways through: -

20


◆ The relationship of residential buildings to each other, to open space (both publicand private) and to the road system.

◆ The location of fenestration such that overlooking of adjoining dwellings isminimised.

◆ The use of adequate screening devices and landscaping elements.

5.8.2 Recommended StandardsAll houses (terraced, semi-detached, detached) should have an area of private open spacebehind the building line. In general the requirement should be 60 - 75m2 minimum for3/4/5 bedroom houses in order to ensure that most household activities areaccommodated and that it is at the same time adequate to offer visual delight, receivesome sunshine and encourage plant growth. A slightly reduced standard may beacceptable where 1 and 2 bedroom houses are proposed but in no instance should afigure of less than 48m2 per dwelling be acceptable. A minimum standard of 22 metresbetween directly opposing first floor windows should normally be observed (seeparagraph 5.6.1 above). This will normally result in a rear garden depth of 11 metres.However, where adequate levels of privacy are provided, this depth may be reducedprovided that the minimum area outlined above is achieved. If considered appropriate, acondition might be attached to any grant of permission requiring that no additionaldevelopment whatsoever take place within the curtilage of each house save with a priorgrant of permission, notwithstanding the exempted development provisions of the LocalGovernment (Planning and Development) Regulations 1994 (or any amendment orreplacement of said Regulations).

In certain innovative housing layouts, the developer may choose to provide acombination of private and semi-private spaces such as in courtyard layouts etc. Thiscould be in the form of small private terraces for each dwelling opening directly onto asemi-private enclosed landscaped space solely for the use of the residences which directlyadjoin this space. In such cases, it may be considered appropriate to accept the sum of thearea of both spaces as satisfying the private open space requirement for these dwellings.

It should be required that, in the case of apartment and duplex style schemes, privateopen space will be provided in the form of landscaped areas, courtyards, terraces/patiosand balconies. Roof gardens should also be considered, provided that they are easilyaccessible, secure and attractively landscaped. Recommended minimum standards shouldrange from:

◆ 10 m2 per one bedroom apartment

◆ 15-20m2 per two or three bedroom apartment

close to City and Town Centres to:

◆ 20m2 per 1 bedroom apartment

◆ 30-40m2 per 2 or 3 bedroom apartment

in the outer suburban areas.

5.9 Car Parking and Road Standards

5.9.1 Current PracticeMost Development Plans include detailed objectives in relation to road design and carparking in residential areas. These standards generally relate to widths of roads and

21


footpaths, radii at junctions, sightlines and gradient. In practice, traditional standardshave led to many rigid and regimented housing layouts where the car is dominant andlong straight roads encourage speeds in excess of maximum limits. Very few Plans includeobjectives relating to the use of shared surfaces, traffic calming or grouped car parkingarrangements.

5.9.2 Recommended StandardsIn considering higher residential densities and the accompanying objective of creating a more urban form in new developments, it follows that roads and car parking standards must be considered in more detail. The aim should be to encourage initiative and innovation, while ensuring that the maximum safety standards are maintained. Authorities should base their assessment of other types of layout on guidance contained in publications such as “Places, Street and Movement” (DETR,1998) and the earlier “Layout of Housing Roads Design Guide” (DOE, Northern Ireland1988).

The Department of the Environment and Local Government has recently (1998)published a new edition of “Recommendations for Site Development Works for HousingAreas”. This publication is primarily concerned with construction standards for sitedevelopment works. However, it does include some residential road standards relatingspecifically to traditional type housing layouts. Those standards are not intended to becomprehensive and relate to traditional type housing layouts only but authorities shouldhave regard to these recommendations, where applicable.

5.9.3 Off Street Car Parking StandardsCurrent parking standards vary considerably between planning authorities but aregenerally in the range 1-2 spaces per dwelling.

Parking standards exert a significant influence on the form of residential development, itsenvironmental quality, and the intensity with which sites can be developed.

Different arrangements of parking (on-plot, group, etc.) also require different amounts of site area and can significantly alter the perception of the impact of cars in the visual environment. Considerations such as the visibility of residents’ cars, convenienceand the need to soften the impact of grouped parking by landscaping should be borne inmind.

Sustainability objectives require a careful consideration of car parking standards.Increasing standards in areas with low accessibility to public transport intensifies thedependence on the private car and has implications for local road networks. Lowerparking standards in these areas on the other hand create inconvenience and illegalparking. A balance is required to counter these opposing principles.

5.9.4 Recommended StandardsPlanning authorities should consider a relaxation in car parking standards in towncentre/‘brownfield’ locations and also in suburban areas proximate to public transportnodes and corridors subject to any necessary parking control measures. Elsewherestandards must reflect the desire for mobility and accessibility without compromisingsustainability objectives. The encouragement of grouped parking for example, canfacilitate flexibility while making a more efficient use of land. A more widespread use ofunderground car parking can achieve the same objective while freeing up greater areas ofthe site for landscaping purposes.

22


23

5.10 Internal Space Standards

5.10.1 IntroductionAny policy which promotes the incorporation of higher residential densities must takeinto account the need for proper internal space planning which ensures adequatestandards in relation to overall dwelling and individual room sizes.

5.10.2 Current PracticeIn general, planning authorities in Ireland do not set out detailed internal space standardsin Development Plans. In practice, it would appear that market forces have been the mainguide factor for the setting of space standards.

5.10.3 Recommended StandardsIn the absence of detailed contemporary standards in relation to internal space standards,it is recommended that those set out in “Guidelines on Residential Developments inUrban Renewal Designated Tax Incentive Areas” (Department of the Environment 1995)should be applied as an absolute minimum for apartment developments. With regard tolocal authority dwellings, the “Memorandum on the procedures to be followed and thestandards to be provided in Local Authority dwellings” (Department of the Environment,1982) has been replaced by the “Social Housing Design Guidelines” which issued on 1September, 1999.

Planning authorities should encourage the provision of dwellings in higher densitydevelopments which are capable of being extended. Aside from the normal single storeyextensions, the conversion of the attic space for additional floorspace should be promotedas a method of providing extra living/sleeping space or storage without increasing sitecoverage.

5.11 Ecology and Bio-diversityHousing sites should be examined and consideration given as to whether their ecologicalvalue has any implication for the location and density of future housing. On sitescontaining areas of significant ecological character, there may be an argument forincreasing density in a particular part of the site in order to limit development on theecologically sensitive part. Layouts should encourage bio-diversity by preserving andproviding cover for species and where appropriate avoiding the culverting of watercourses and providing new water areas. Planting should normally use native tree andshrub species and native stock; tree species with berries are important for wintering birds;trees which support a high biomass of insects in summer are important for breedingbirds; the setting aside of maintenance free areas and the avoidance or limitation of theuse of herbicides and pesticides are all practices which will encourage bio-diversity.


24

6.0 ‘Taking in charge’ and Managementof Residential Estates

Residential estates are generally designed in accordance with development controlstandards which are aimed at the longer term taking in charge and maintenance of thepublic roads, footpaths, services and open spaces, by the Local Authority.

With the evolution of apartment developments in the 1970s and 1980s, an increasingnumber of residential schemes have been privatised and are maintained on a permanentbasis by private management companies. It is possible that privately managed estates willincrease in popularity in the coming years. It is also possible that schemes other thanapartment and small townhouse developments will become privately managed and thelocations of such developments will not be restricted to inner suburban/city centrelocations.

In the context of higher densities it will be necessary for planning authorities to givecareful consideration to what impact the design objectives set out elsewhere in theseGuidelines will have on their ‘taking in charge’ standards. The concept of smaller butmore intensively landscaped open spaces, the promotion of group car parkingarrangements and the incorporation of shared surfaces in smaller mews courts andstreets, will have a significant impact on the more traditional housing layouts and haveimplications for the way in which estates might be managed and maintained.

Planning authorities should review and update their ‘taking in charge’ standards in thelight of the overall objectives set out in this document.


25

APPENDIX 1 – List of Relevant Publications

Building Research Establishment (1991) “Site Layout Planning for Daylight and Sunlight: A Guide to GoodPractice”

B.S. 8206 “Lighting for Buildings, Part 2 1992: Code of Practice for Daylighting”

Department of Environment and Local Government (1997) “Social Housing Guidelines - Site Selection”(DoE)

Department of the Environment and Local Government (1997) “Sustainable Development - A Strategyfor Ireland”

Department of the Environment and Local Government (1998) “Circular Letter PD4/98 ResidentialDensity” (DoE)

Department of the Environment (1995) “Guidelines on Residential Developments in Urban RenewalDesignated Tax Incentive Areas”

Department of the Environment (1982) “Memorandum on the procedures to be followed and the standardsto be provided in Local Authority dwellings”

Department of the Environment and Local Government (1998) “Recommendations for Site DevelopmentWorks for Housing Areas”

Department of the Environment, Transport and the Regions, (UK) (1998) “The Use of Density in UrbanPlanning”, London HMSO

Department of the Environment, Transport and the Regions (UK) (1998) “Places, Street and Movement”,London HMSO

Department of the Environment (Northern Ireland) (1988) “Layout of Housing Roads Design Guide”

Environmental Protection Agency (1996) “State of the Environment in Ireland”

Llewelyn Davies and LPAC (1998) “Sustainable Residential Quality: New Approaches to Urban Living”

Peter Bacon & Associates (1998), “An Economic Assessment of Recent House Price Developments” (DoE)

MacCabe, McCrossan O’Rourke, Jones Lang Wootton (1999) “Planning Issues Relating to ResidentialDensity in Urban and Suburban Locations”

Department of the Environment and Local Government (1999) "Social Housing Design Guidelines"


APPENDIX 2 - Glossary of Terms

Gross DensityGross Density is an appropriate standard where development will take place on a number ofneighbouring sites and where these have not yet been accurately defined. In such cases, the definitionof the site/development area includes major and local distributor roads, primary schools, churches,local shopping etc., open spaces serving a wider area and significant landscape buffer strips which maydefine the site boundary/development edge and the density assumption applied will need to reflect theinclusion of these elements.

Net DensityThe measurement of net density includes only those areas which will be developed for housing anddirectly associated uses and will include: -

◆ access roads within the site

◆ private garden space

◆ car parking areas

◆ incidental open space and landscaping

◆ children’s play areas where these are to be provided

Plot RatioPlot ratio expresses a relationship between the area of a site and the total gross floor area of the building/s whether existing or intended to be erected on it. It is determined by the followingequation:

gross floor area of building/s = plot ratio.

site area d

Gross floor area is the sum of floorspace within the external walls of the buildings, excluding plant and tank rooms and car parking areas. Site area relates to the area of the development site and in the case of ‘greenfield’ sites would include access roads, car parking areas and open spaces within thesite.

Site CoverageSite coverage is determined by dividing the total area of ground covered by the building/s by the totalground area within the curtilage of the building/s excluding any land lying between the building lineand the public street.

Brownfield SitesAny land which has been subjected to building, engineering or other operations, excluding temporaryuses or urban green spaces.

Greenfield SitesPotential development land on the periphery of urban settlements having no previous building on it.

26


27

Quality Public Transport CorridorA route with dedicated, high frequency and reliable public transport service/s which are accessible,user-friendly and integrate with other parts of the public transport network. The primary catchmentfor quality public transport corridors extends to: -

Rail - lands within 1 km distance of a stationLRT - lands within 1 km distance along the routeBus - lands within 500 m along the route

Single Aspect HousingHouses which have their main sleeping and living areas on one side and circulation and bathrooms onthe other.

residential density - kerry county council · guidelines for planning authorities on residential...

Documents