How Compact is Sustainable—How Sustainable is Compact?
This apparent contradiction in concepts poses the question as to what is meant by compact. Does it mean that buildings, and with them the functions of urban life, should be close together; closer together than is now common? Does it mean, inter alia, an increase in density, so that more people and, one might expect, more urban functions are located within a given area? The question sharpens the distinction between density and intensity of development, for they are not the same thing. Density is a quantitative measure of number within a prescribed area, whereas intensity reflects a more subjective measure of built-up-ness or urbanity. Density, in itself, is of little importance unless it is related to built form. Compact is meaningless unless it is related to some facts and figures. This century bears witness to a vast catalogue of attempts to arrive at a better understanding of the relationship between density and built form, especially in housing and especially in Britain. Some pernicious critics might describe these attempts as crimes and misdemeanours! Therefore, it seems necessary at the outset to place housing densities into some form of perspective against their respective built forms. Ebenezer Howard’s ‘garden city’ reaction to the squalor and overcrowding of the nineteenth century meant 45 houses to the hectare, which at an average four bedspaces per house is 180 bedspaces per hectare (Howard, 1898). Raymond Unwin advised that there was Nothing Gained by Overcrowding and his ‘town’ density, enshrined in the Tudor-Walters report which regulated the four million inter-war dwellings with gardens, and rehoused one third of the population of England and Wales, was 30 houses to the hectare, or 120 bedspaces per hectare (Unwin, 1912). Patrick Abercrombie’s three pyramidal, residential density zones for London’s postwar reconstruction prescribed 247, 336, and 494 people per hectare (Abercrombie, 1944). For bedspaces read peopleboth indicate the intended or designed maximum-rather than average density; the latter reflects occupancy rates which, today, are substantially less than actual bedspace potential, whereas in times of overcrowding are substantially more.