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SUSTAINABLE SUBURBIA | RICHARD MACCORMAC

Sustainable Suburbia

R i ch a rd MacCormac demonstrates that it is possible to ach i eve a pedestri a nc o m munity wh i ch brings a viable public tra n s p o rt system and the many fa c i l i t i e su s u a l ly associated with an urban env i ro n m e n t , within ten minutes' wa l k .

Sir Richard MacCormacis a chairman ofarchitects MacCormacJamieson Prichard

The challenge of climate change forour society is whether we canreconcile our lifestyle expectationswith the measures which will benecessary to sustain our environment.

Traditional suburbia evokesimages of excessive land use, socialfracture and car dependence. (Fig 1)Our ongoing study 'SustainableSuburbia' sets out a spatial strategywhich reconciles essential qualities ofsuburbia with efficient land use, andwith walkable communities whichneed not be car dependent.

The suburban aspirations offamily housing – a mainstreamsegment of the market – usuallyassociated with low densities, can beachieved at much higher densities,which offer a range of communal andstrategic advantages usually associ-

ated with urban contexts. In thisway, private and communal advan-tages can be reconciled.

The essential characteristics ofeach can be set down as shown inthe table. The communal objectiveshave strategic implications forplanning authorities and meetgovernment objectives set out inPPS3. But they also have implica-tions for volume housebuilders whowill have to realise these PPS3 objec-tives in the planning process.• Create more sustainable patterns ofdevelopment which deliveraccessibility by public transport foremployment, education, localservices, shopping and recreation• Make more efficient use of land• Give priority to pedestrians overvehicular movement• Reduce car dependence• Promote the design of high qualityliving environment

Our investigation of densityincludes five design studies forhousing layouts which achieved arange of densities from 50 to 120dwellings per hectare. At 50dwellings per hectare the dwellingtypes are three-bedroom houses withgarden and associated off-streetparking at 100%. As the densitiesincrease there is a higher proportionof maisonettes in mews-like layoutsappropriate to inner suburbs or thecity edge. (Figs 2,3,4,5,6)

Our investigation goes on toconsider how a community could be

created with suburban housingwithin walking distance of local facili-ties and transport. Research by DETRand others suggests that a viableregional transport link needs fivethousand dwellings within tenminutes' walk. An LDA study sets outthe local services that five thousanddwellings will support. What wehave found is that 5000 dwellings ata density of 50 dwellings per hectarecould create a settlement of 113hectares (of which 100 hectares arehousing) with a radius of 600 metres.This would bring a central transportlink and a range of facilities withinten minutes' walk of everyone. Thiscould meet the Government objec-tives set out in PPS3. (7)

The further development of thisidea analyses the spatial conse-quences of combining various ratiosof family housing with one- and two-person flats.

If a combination of 50% flats at150dph and 50% family housing isassumed, a surprising 33% of the onehundred hectares becomes availablefor open space or other uses stillwithin an overall density of 50dwellings per hectare. (8) (9)

Other options become possible;the overall density could be increasedto 60 dwellings per hectare (increas-ing the number of dwellings from5000 to 6000) or the family housingdensity could be reduced to 40dwellings per hectare increasing plotsize or creating more varied housing

Fig 1Greenleys, Milton Keynes

Off-street parking: 100%• Very inefficient in terms of land in private useRoad systems and open spacepatterns across the whole settlement reducegross density to perhaps 7du/ha% Roads: 20% ‘SLOAP’: 40FAR: 0.4

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SUSTAINABLE SUBURBIA | RICHARD MACCORMAC

group combinations, still within theoverall average density of 50dwellings per hectare.

Basically this offers a methodol-ogy for a systematic approach forregional planning bodies, localauthorities and regeneration agenciesto assess the housing capacity ofurban and suburban areas in relationto mixes of different types of housingand densities appropriate to locationswithin and outside existing urbanareas. It is an approach which couldwork in conjunction with theNational Land Use Database (NLUD).

The objectives of this quantitativeapproach to spatial strategy forefficient land use must, however, bequalitative objectives and lead tobetter places for people and greenerand more ecologically sensitiveresidential environments.

What follows is a hypotheticalcase study focused on the idea of agreen residential environment inwhich landscaping is integral, biodi-versity is sustained, and variety ofpublic spaces makes walking and

2 Courtyard HousingD e n s i t y : 57dph net 285 bph netHousing Mix: 100% 3b 5p housesS t o r e y s : 2Off Street Parking: 1 0 0 %Proportion of Road: 3 6 %

3 Terraced Court HousingD e n s i t y : 77dph net 383 bph netHousing Mix: 90% 3b 5p houses

10% 3b 5p maisonettesS t o r e y s : 2 / 3Off Street Parking: 1 0 0 %Proportion of Road: 3 2 %

4 Mews HousingD e n s i t y : 87dph net 435 bph netHousing Mix: 69% 3b 5p houses

31% 3b 5p maisonettesS t o r e y s : 2 / 3Off Street Parking: 1 0 0 %Proportion of Road: 4 0 %

5 Mews Housing with terraced maisonettesD e n s i t y : 111dph net* 528 bph net*Housing Mix: 43% 3b 5p houses

24% 3b 5p maisonettes*12% 2b 4p maisonettes*

S t o r e y s : 2 / 4Off Street Parking: 9 4 %Proportion of Road: 3 5 %

6 Mews Housing with flats and maisonettesD e n s i t y : 120 dph net* 482 bph net*Housing Mix: 52% 3b 5p houses

18% 1b 2p flats*12% 3b 5p maisonettes*12% 2b 3p maisonettes*6% 1p studio flats*

S t o r e y s : 2 / 4Off Street Parking: 7 6 %Proportion of Road: 3 2 %

* The proportions and dwelling types can be varied

Fig 2

Fig 5

Fig 6

Fig 4

Fig 3

Fig 7

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SUSTAINABLE SUBURBIA | RICHARD MACCORMAC

cycling and taking children to schoolan interesting and refreshing experi-e n c e .

Combining a proportion of one-and two-person flats at a higherdensity with family housing creates amore diverse demography of young

and old, families and single people.The mix of density and dwelling

type proposed is 30% one- and two-person flats at 150 dwellings perhectare and 70% family houses at 50dwellings per hectare. (10) Thisyields a land use of 10% apartments, 70% family housing and 20%

released for open space and otheruses (in addition to the 13 hectaresalready allocated for local facilities).(11). 20% is a large area – 20hectares out of 100. (12)

An even distribution in a chequerboard pattern would give everyhousing group immediate access toopen space while maintaining theoverall density of 50 dwellings per

hectare. This is a quadrant of 1250houses. (13)

But it could be much more inter-esting to consider open space as ameans to creating local identities thewith a deliberately uneven distribu-tion as it might be in an existing smalltown. (14)

The sketch suggests howlandscape might intensify the varietyof the settlement. (15)

A characteristic of much volumehouse-building is to seek variety withcurving road systems to whichhousing layouts react informally.This tactic may provide identity at asmall scale, but the overall effect ofrepetitive variety is paradoxicallym o n o t o n o u s .

The sketch plan begins to explorea layout in which open spaces ofvarious sizes are incorporated.Consequently journeys, particularlythose on foot, encounter varioussequences of space and of differing

Figs 8 & 9

Fig 13

Fig 15Fig 16

Fig 17

Figs 10 & 11

Fig 12 Fig 14

landscape character, enjoyable towalk through. (16)

The following studies are orthogo-nal to assist our methodology not asa necessary objective but it is noaccident that they are more like aGeorgian suburb than a modern one.

The first study is based on alayout cluster 26 houses of five-metre frontage with back gardensand 1:1 parking at a density of 50dwellings per hectare sharing aninternal courtyard for communityand children's activities.Permutations could include flats ormaisonettes as part of the cluster andvarying configurations of car-parking.( 1 7 )

The clusters can be combined into

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Figs 18, 19, 20, 21

Figs 22 above, 23 below

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larger groups and open spaces madeby omitting clusters. (18) (19)

Large open spaces can be made byomitting groups of clusters. Housesmight front onto a formal square inan eighteenth century arrangement.(20). Houses might back onto asecluded recreational area shared bythe properties bounding it, like partsof Holland Park. (21)

The cluster establishes the intervalof streets and intersections offering ahigh degree of permeability. Flatsraise the density locally. (22). Allhouses have back gardens openingonto enclosed courtyards. Theenclosed courtyards can provideshared and secure children's playspace for each cluster. (23) (24)

Larger open spaces can be sharedby the whole community and withroads and footpaths contribute to theease of pedestrian and cyclemovement. A strong pattern oflandscape varies and intensifies thecharacter of each open space andoffers ecological richness across thewhole development. (25)

C o n c l u s i o nIn a community of over 5000

dwellings at a density above 50 dphor densities varying around anaverage of 50 dph we demonstratethat it is possible to achieve a pedes-trian community which brings a

viable public transport system andmany facilities, usually associatedwith an urban environment, withinten minutes' walk. A mixture ofdwelling types including one and twoperson flats can increase densitiesfurther, extending the range of choiceof facilities and local employmentand opening up the potential of amore diverse demography of youngand old, families and single people.

But, the higher density achieved witha mix can also lead to a much greenerresidential environment in whichlandscaping is integral andcontributes to recreation, energyefficiency, storm drainage and biodi-v e r s i t y .

A fundamental characteristic ofour proposal is that gross densitiesacross a community sustain the netdensities of housing groups. This is

the key to efficient land use andsustainability and requires a newapproach to highway engineeringwhich rejects distributor roads whichdilute density, in favour of permeableroad networks which sustain density,reduce traffic speed and create amore pedestrian-friendly and neigh-bourly environment. Such anapproach can significantly reduceland use and infrastructure costs.

Fig 24 below, 25 right