Paris residential streets
Site diagram, density figures
New construction, modest scale
REPLICATING PARIS DENSITY AND STREETSCAPE IN NEW CONSTRUCTION
The city of Paris is often cited by architects and planners as their favorite place to visit. Parisians and visitors alike never tire of walking her narrow, winding streets, with continuous ground level boutiques and cafes. They enjoy the quiet gardens and public places. They may not take into consideration that most of the old city has a uniform building height. During the Haussmann era, the nineteenth century, architects were required to build “immeubles”, (apartment buildings), no higher than the tower of Notre Dame, or about 100’. This typically produces a six-story building with “Rez-de-chaussee” (ground level) and “combles” (attics). The population of Paris is approximately 2,156,190, covering an area of 41 square miles, 52,590 people per square mile.[i] The result is a certain density and a certain proportion of street to building. This density is found to be ideal for supporting continuous retail space, and therefore a walkable city. It has also been found to be a human scale, not too tall to be alienating to the dwellers or the passers-by.
Yet few architects and planners plan their own communities in this manner. They often plan towers with large planted spaces between them. Parking is often accessed at ground level. The view from the dwellings may be beautiful but the higher units are alienated from city life. This type of plan also leaves many gaps in the walking paths, discouraging pedestrian activities as well as retail development. Planners often claim that they build higher buildings because of land costs and to achieve higher urban densities. But is this actually the case?
In Residential Design Studio[ii] , we have sought to compare densities of different housing types on an “apples-to-apples” basis (same site, different structures). In the chapter on Urban Design, a variety of housing types are placed on the same 5 acre site, a typical urban block, for many American cities, like Chicago. The results are somewhat surprising. Towers produce a marginally higher density but a fair amount of space must be left between them to insure a modest amount of sunlight to enter the units. The six-story mid-rise building, (the Parisian prototype), produces about 92 dwelling units per acre, while the tower blocks 100-125 dwelling units per acre.
One of the difficulties of comparing densities is the different ways they are measured, e.g. Dwelling Units/Acre or People/Acre. Sometimes Dwelling Units or People/Square Mile is used.[iii] For Paris, the French Land Register shows a gross average density of 35,326 dwelling units per square mile (translated from kilometers) or about 52,590 people per square mile. (About 1.48 people per dwelling unit).
A group of towers might be connected by one-story retail structures for pedestrian continuity, and the scale of the towers could be broken up into smaller sub-groups, but there still is the matter of heights. Planners, architects, and residents may disagree as to what is a maximum height allowable for buildings, but the economics of small scale retail and pedestrian continuity, as well as visual scale, are more objective means of comparing densities.
We decided to imagine a Paris density and residential scale applied to a typical block in an American city. From center lines of street, the block area is five acres. By planning a six story residential building, with ground floor retail, we are able to achieve 460 dwelling units, or 92 dwelling units/acre. At 1.5 people per dwelling unit, that would be 44,160 people per square mile, or about 84% the density of Paris. Our diagram shows considerably more internal open space, as well as the potential for a service alley.
Can we then presume that planning new communities with a “Parisian density” is achievable and desirable? Can you imagine walking down a street in Chicago, shopping in a farmers market for fresh, local produce, buying a newspaper at a small kiosk and then stopping at your local café? Continuing on to visit a myriad of small business owners whom you know on a first name basis? They provide useful goods and services not available at the big box stores. There could be shops that include shoe repairs, seamstress, specialty goods, a baker, a fresh meat butcher, stationery and office supplies. Yes we would like to have that kind of neighborhood in Chicago or other American cities. It would take serious planning efforts for new urban design that support the values of walkability and sustainable small businesses. And we should support those plans wherever possible. It’s cheaper than air fare.