Today we’ll cover chapter 9 of Raymond Unwin’s ‘ Town planning in practice; an introduction to the art of designing cities and suburbs‘ of 1909.
Unwins begins the chapter with a discussion of the victorian by laws which allowed development of tight terraces with rear yards of only 25′ depth – which with narrow frontaged cottages Unwin considered inadequate for health and comfort.
It is not possible to fix any absolute limit for the number of houses to the acre which can be regarded as a maximum compatible with health and comfort. Very much depends upon the size of the houses and their arrangement. It is not easy yet to weigh the disadvantages that might arise from enlarging our towns to such an extent as would give a much lower number of houses to the acre all through, but one may safely say that, according to circumstances, the desirable number would be between 10 and 20 houses to the acre, and in this case I refer to the net measurement of the building land, excluding roads. There will necessarily be areas in the centre of towns where buildings will be crowded to a greater extent than this figure would suggest ; but in any district where cottages are likely to be built it should not be necessary to exceed the maximum number of 20, and wherever possible the number should be reduced to 10 or 12.
The figure of 12 DPA is often given as a rigid maximum for ‘Garden Cities’ but you can see that Unwin was not that rigid, especially for areas at the centre of towns. Indeed 12 DPA is not that low a density, especially when compared to sprawling American and Australian suburbs.
Indeed 12-20 DPA magically comes out at 30-50 DPH, exactly the recommended minimum density ranges from the old PPG/PPS3. And we know that even large family dwellings can be provided at 50 DPH where 2-33 storey terraced townhouses are used, as at Bedzed. We also know that family housing can be provided in streets appearing as single family dwellings at 100DPH if certain ‘old urban’ techniques are used, as in the Swedish new town of Jakriborg, which is very similar in form to the kind of central city plans that Unwin favoured.
12 DPA was the favoured number simply because of the practicalities of cultivation as it was an essential supplement to labourers wages, such considerations are less important today as not eveyon will cultivate and accessible allotments may in many circumstances be preferable to excessively large gardens which we now know in social housing will simply see quite a large proportion left untended.
Twelve houses to the net acre of building land, excluding all roads, has been proved to be about the right number to give gardens of sufficient size to be of commercial value to the tenants — large enough, that is, to be worth cultivating seriously for the sake of the profits, and not too large to be worked by an ordinary labourer and his family….
it is only the average number of houses to the acre that needs to be very carefully considered from the point of view of health, the exact size of each garden being a matter of comparative indifference. This figure of 12 houses to the acre has now been fairly well tested, having been adopted in the main at Bournville (although here there are some larger gardens), at Earswick, at the Garden City at Letchworth, at Hampstead, and at many other places. That a greater number of houses to the acre than 12 may be planned, and yet produce a healthy suburb is proved onthe estate of the Ealing Tenants and many others.
in terms of cottages Unwin recommended a minimum frontage width of 15 feet for two bedrooms (4.6m) and 18-20 feet for three bedrooms (5.5-6.1m), varying depending on aspect. For plots 150 feet deep and 12 houses to the acre an average frontage of 24 feet is obtained (7.3m). This leaves 100 yard (91.4m) distances between parallel roads. If there was a significant reduction in these distances then any variation in grouping would bring houses too close together at the back.
Unwin talks of the Garden City (Letchworth then) bye laws where one rule was that the building occupied no more than 1/6th of the site. With exceptions for shop and corner sites.
Unwin was critical of the ‘apparent economy’ of narrow long plots as crossing roads in between permiter blocks (as we would call them today) become longer. He also to the type of dark bye law house with ‘long projections running out behind’. The architectural term for these is outriggers.
Unwin said:
It is quite a mistake to suppose that it is always economical to put the maximum number of houses which can be contrived on any space…Cases may frequently occur where the loss of ground to provide an additional cross road to open up the centre of some area of land, and the cost of the road itself, when taken together are not compensated for by the increased value of the central area of land thus developed, and it may often be wiser to reduce slightly the number of houses to the acrerather than to cut up the land with too many roads.
Of course this was the key argument in his fanmous 1912 pamplet Nothing gained by Overcrowding. Today the argument requires some modification as the house /road cost ration is somewhat different and the key argument is now not losing to roads what land could be used for housing.
Of course where inexpensive, subsidiary roads such as have been used in the Hampstead Garden Suburb estate are allowed, it would be possible to utilise this area of land to form a green in front J of the houses on the main road, thus producing an attractive feature in the road, and at the same time securing an additional number of houses by the increased frontage provided around the green.
Though here we have the invention of the cul-de-sac there are four critical variances from modern culs-de-sac non grid layouts, secondly they were for Unwin subsidiary elements, seodnly they did not force a tree form of layout, thirdly they were often car free with central greens, and finally they fiten had filtered permeability to allow pedestrian access to the other side of the permiter block.
A critical element of housing design for Unwin, sadly almost never utilised today was to vary the housing layout and housing plan by aspect to optimise sunlighting and ensure principal rooms gained sufficient sunlight.
to secure the best result possible from any site the architect who plans it should be in close co-operation With the designer of the buildings
Sadly most architects today seem to have had no training at all in site planning and such issues seem like a bolt out of the blue revelation when you do mention it to them concerning the laying out of a site.
Unwin was a great critic of the ‘platting first’ approach to site planning, sadly prodominent especially in American planning. We might call it Unwins ‘buildings first’ law of town planning.
it is the buildings which must be the primary consideration in laying out the site ; so much so that the designer, if he is wise, will lay out his buildings roughly, not only before he considers the division of his plots, but before he fixes the exact lines of his roads. If he is content with merely cutting up his spaces into what he will ‘ lettable’ plots, there is little likelihood of any beautiful result or satisfactory group ing of the buildings which will be placed on them. Having laid down approximately the position of the roads, the right placing of the buildings must then command his attention; he must decide on the main building lines and masses, placing any important features in his design, such as the terminal feature at the end of a road, or any buildings required to limit the size and give a sense of frame to the street picture which he is dealing with. Having placed his buildings roughly and decided on the general picture which he is desirous of obtaining, it will be time enough then to consider the plotting of the land, working from these important and fixed points. It is usually easy to adapt the boundary lines of the plots to suit the buildings, much easier than to adapt the arrangement of the buildings to any preconceived plot lines.
And on the backs of plots:
Nothing more thoroughly expresses the shoddy character of our modern town development and the meanness of the motives which have inspired it than the treatment of the spaces at the backs of buildings. It seems to be forgotten that from all the houses around such a space the outlook of the inhabitants must be on to the backs of their neighbours houses opposite, but just because these are not seen from the public street outside all attempt to make them even passably decent according to the excessively low standard which governs the fronts of such buildings has been neglected. The removal of the excessive back projections will of itself be a great improve- ment, but a little care in the arrangement of the houses and in their design may very often make the spaces at the backs as beautiful as or even more beautiful than the fronts.
Unwins approach to ‘attractive outlook’ from houses was thoroughly democratic.
it is for the site planner who is engaged in laying out sites for smaller houses, where each cannot stand in large grounds of its own, to secure for as many as possible of these houses some extent of outlook by arranging breaks in the street line, by setting the houses back round greens, by planning his roads so that they may command some distant view or may lead on to some open space ; and wherever a specially fine view is obtainable, by grouping as many of the houses as possible so that they may enjoy it.
Hampstead Garden City being a great example of how Unwin maximised view of the Heath Extension. .
Unwin paid great attention to corner sites,
The usual modern bye-laws as to open space, requiring as they do that this space shall oe at the rear of the building, and making little or no provision for corner sites, has resulted in the production of the most unsatisfactory treatment of street corners ; and their ugliness has been exaggerated by the want of care in the treatment of the ends of the buildings at the corners of side streets, Some liberty should be allowed in the treatment of corner sites.
Not simply in terms of creating his famous ‘street pictures’ but in terms of economy of layout as where two streets meet rear garden space can be squeezed. Unwins solution is the famous garden city open areas at corners, including sometimes houses angular to corners substituting side and frontage space for squeezed rear gardens.
Unwins treatment of this issue is supplemented by a considerable number of illustrations of possible corner treatments and I can only recommend reading the original on this point.
Unwin talked of the prejudices of the public in favour of detached and semi detached houses, and of course they are easier to light and ventilate with windows and three or four sides. But Unwin stressed that grouped terraced houses could obtain similar advantages in groups of three to five houses if the central ones had ‘ample frontage in proportion to their areas’
Taking English Village Greens and cathedral closes as his models for grouping he says:
The tendency of the modem individual has been to build his house in such a way as to emphasise its detachment and difference from its neighbours, but no beauty can arise from the mere creation of detached units. So long as we are confined to the endless multiplication of carefully fenced in villas, and rows of cottages toeing the same building line, each with its little garden securely railed, reminding one of a cattle-pen, the result is bound to be monotonous and devoid of beauty. It must be our effort to counteract this tendency and to prove that greater enjoyment to each householder can be secured by grouping the buildings so that they may share the outlook over a wider strip of green or garden — in fact, that by some degree of co-operation more enjoyment of the available land can be secured than by dividing it all up into individual plots, and railing each in.
Indeed Unwin was not a fan of front fences, they secured little in the way of privacy or protection from dust. He had seen the American tradition of open frontages and much admired them, although acknowledging that to the English enclosure was an essential feature of the garden, so naturally he preferred hedges and shrubberies instead.
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