Housing density & design

1. Housing density & design

2. What is housing density? • Housing density or residential density refers to the number of homes per unit of land.It is typically reported in dwelling units per acre (or du/ac). The typical single family neighborhood in Los Angeles is about 5-8 houses per acre.

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4. How is density measured? • In the Los Angeles zoning code density is measured as dwelling units per square feet of land. • In the R3 apartment/condominium zone the maximum density is one unit of housing per 800 square feet of land. • This is about 54 units/acre =0.405 ha= 4050 sqm.

5. Housing density The amount of housing in a given area • Density is used in planning for new residential development to measure the amount of new housing to go on land. • Government policy requires local planning authorities to plan for • new housing to be at a density no lower than 30-50 dwellings per hectare.

6. England / London Metropolitan area In London, density is measured in terms of 'habitable rooms' per hectare, and local planning authorities in London require densities that are in practice usually much higher than the minimum range. Government policy also defines density as 'net' density, which includes garden space, access roads and car parking, but not major roads or large public open spaces. encourages a higher density of retail and office development, but does not lay down a minimum density.

7. Badly designed high density housing can make a development feel cramped, oppressiveovercrowded,lead to a ‘sea of cars’.

8. Getting density too low leads tosprawl, feelings of isolation, car dependency can undermine the viability of public transport.

9. The Government’s Planning Policy Guidance (UK) ‘Local authorities should avoid inefficient use of land. New housing development inEngland is currently built at an average of 25 dwellings per hectare but more than halfof new housing is built at less than 20 dwellings per hectare. That represents a level oflandtake which is historically very high and which can no longer be sustained….

10. Localplanning authorities should avoid development which make • inefficient use of land • (those of less than 30dwellings per hectare net); • encourage housing development which makes more efficient used of land (between 30 and 50 dwellings per hectare net); search greater intensity of development at places • with good public transportaccessibility such as city, town, district and local centres’ • urged to ‘reject poor design’ and • to ‘thinkimaginatively about designs and layouts which make more efficient use of land withoutcompromising the quality of the environment’.

11. Residential Density: Density is a measure of the intensity of development of a residentialplot :It is conveniently measured in habitable rooms per hectare. (hr/ha.) The formulae tocalculate density Density= Number of Habitable rooms X 10000 sqm /size of the area Habitable rooms are all rooms except: • bathrooms and WCs • laundry rooms • storage cupboards • passages and hallways • kitchens of less than 13 square metres. Net residential area includes: The part of the site used for residential purposes Gardens Incidental open space Half the width of surrounding roads up to a maximum of 6 metres. In mixed use proposals, where non-residential and residential uses are combined on one site, the method of calculation will depend on the size and configuration of the site, and the scheme layout.

12. New Housing • In assessing proposed residential developments, including conversions, • the space to be provided for individual dwellings will be an important • factor in the quality of the accommodation to be provided, and in the • impact of the proposed development on the character and amenity of the surrounding area. • The Council will have regard to the standards set which are considered relevant to the Borough and likely to achieve the relevant policy objectives. • Wheelchair standard housing: Accessible Housing has greater floorspace requirements.

13. The briefing focusing is: • At the way density and parking standards are being used • The importance of good design over and above crude standards. It then explores the issuesin a number of local situations. • The inserts provide illustrated examples of • how thequality and design of new housing development can be improved • on infill sites invillages and towns • on an edge-of-village site. • It is also hoped to extend this guidance with real life examples from around thecountry aswhen they appear • CPRE would welcome information on good • examples of such development.

14. Defining density • As passers-by or residents we experience density mainly from visual clues. Impressionsof ‘high’, ‘low’ or ‘OK’ density are influenced by many things, including: • heights ofhouses; • spaces between them; • breaks and variety in building blocks; • heights of garden • and other walls; • the amount of any site given over to parking and road; • colour and tone • of materials and • stylistic features.

15. We also read the social clues • about numbers, ages • and mixes of people, • Tenure - ownership, • the numbers of childrenaround. • Nevertheless, no simple rules emerge from this. I

16. In villages in particular, • infilldevelopment of a gap in a street with a terrace right on the pavement • may result in ahigher density figure • than a strip of detached (and set back) houses, • but the terracewould look natural and the ‘lower density’ version out of place. • If anything hints at ‘theanswer’ it is this: • that a scheme that relates well in form and pattern to its surroundings • is likely to be at the ‘right density’ irrespective of any figures. • And don’t forget that many well-loved (and high value) areas in our towns and villagesare built at densities(however one measures it) way beyond even the higher figuresnow being promoted by the Government. • Cornish villages and Georgian town centresare but two examples.

17. Density, design and parking standards • The revised PPG3 is clear about the need to avoid low densities and recommends • building in the range of 30-50 dwellings per hectare and higher in places with goodpublic transport access. • But given the enormous variety in house size a small flat canbe 80 sq m. an executive house 250 sq m. • one scheme of 30 houses can includeliterally: • two or three times as much volume of building • as one of other scheme of 30 houses. CONCLUSIVE COMMENT: Knowing the density in houses per hectare does not tell you whether the development will meet aspirations for locally distinctive design.

19. This briefing helps to show a way forward. It seeks to allay misplaced fears about • increasing densities • to demonstrate the importance of the new planning guidance • to the countryside; • as well as to our major towns and cities. • At the nub of the issue is: • Thequality and design of new building and the briefing shows: • how and where argumentsabout ‘density’ can • and should be used as part (and part only) of the debate that leads • to good quality new housing. • In the final judgement • it is design and not density whichmatters most.

20. There is growing interest in the use of ‘bedspaces per hectare’ • as an alternative tohouses per hectare but it is not included in PPG3. T • his gives some measure of thenumber of people who might be living in a development and so gets nearer the truebuilt and visual density. • But you can never be certain how many bedspaces will beoccupied and • trends towards smaller household sizes suggest the number of bedspaceswill generally exceed the number of people living in an area.

21. from Steve Tiesdell

22. germany • Netto- und Bruttowohnbauland Begriffserlauterung • A = Nettowohnbauland • B = Überbauter Teil des Nettowohnbaulandes • C = Gemeinsame Zubehör­flache; • C1, Flache fur den flief3enden (internen) Vcrkehr, • C2, Parkflache • D =Gemeındebedarfs flachen • E = Überörtliche Verkehrsflache • A + B + C + D = Bruttowohnbauland

23. Muller / Stadtebau

24. How does it look?Imagine a small area of land– a plot on a site big enough for one ‘executive style’house. Here it is, with some figures Variation 1: large family with teenagers seven – eight people and four cars. Variation 2: ‘empty nesters’ • (grown upkids)so two people and two cars. • You could get 20 of these per hectare • (or140/160 bedspaces), so that’s: • Variation 1: 140/160 people and 80 cars; • Variation 2: 40/80 people and 20 cars. Now exactly the same amount of land, the same plot as above but a different kind of development. Illustration 1: a 5 bedroom house With seven – eight bedspaces, Doublegarage and front space (for two morecars).

25. Illustration 2: a flat block with three 1-bedroom and two 2-bedroom flats, plus garage (G) & other parking on plot. • That makes for 14 bedspaces and five carspaces. Variation 1: fully occupied as 14 people • and five cars. Variation 2: lower occupation (somesingles, couples etc.) generates Sevenpeople, still five cars. • As before you can get 20 of these per • hectare (or 280 bedspaces), so that’s: • Variation 1: 280 people and 50 cars; • Variation 2: 140 people and 50 cars. Now once again the same amount of land but different density

26. Illustration 3: two terraced houses, one 3-bedroom and one 4- bedroom, with double garage, plus car space in front.That makes 12 bedspaces Variation 1: If all households are familieswith children, that totals 12 people andfour cars. Variation 2: If it comprises a large familyand a couple, that totals nine people plusthree to four cars. • Once again, there can be 20 of these perhectare • (or 240 bedspaces), • so that’s: Variation 1: 240 people and 80 cars; Variation 2: 180 people plus 60/80 cars.

27. the ‘houses’ and ‘bedspaces’per hectare; • you can see how house type, occupancy and car ownership all vary figures dramatically for Though bedspaces tells you a little more; Assuming general preferences for mixed • house types and • varied occupancy (especially over time) • neither of them measure highlights anyimportant differences that could not be ironed out by good design.

28. Why density matters?High density can provoke a variety of negative reactions…. Such as: • An instinctive dislike of increasing density, • A fear of ‘town cramming’; • An associationbetween high density and high-rise tower blocks (many of which were in fact built atlower densities than those recommended) • Creating ‘skyscrapersin villages’ • Damaging infill areas • Not see the relevance of the new planningguidance to small towns and villages.

29. When done well raising densities can: • enhance and complement the character of an area; • create opportunities for social contact; • sustain public transport; • encourage feelings of safety and security; • absorb parked cars without intrusion; • create a sense of identity; and • maintain, even improve, local property values.

30. As a result • Doing this across the country • can help to make more sensible use of land in towns and • villages, reduce pressure on greenfield sites, sustain local services and contribute torevitalisation.

31. This briefing helps to show a way forward. It seeks to allay misplaced fears about • increasing densities • to demonstrate the importance of the new planning guidance • to the countryside; • as well as to our major towns and cities. • At the nub of the issue is: • Thequality and design of new building and the briefing shows: • how and where argumentsabout ‘density’ can • and should be used as part (and part only) of the debate that leads • to good quality new housing. • In the final judgement • it is design and not density whichmatters most.