Enabling responsible urban form

[M II A II R II K]

ENABLING RESPONSIBLE URBAN FORM


http://www.theurbanvision.com/blogs/?p=717

The term “density” has developed a tarnished reputation in our time. It has become synonymous with mid and high rise buildings, typically designed as homogeneous, repetitive, self-referential projects that rarely respond to their adjacencies, surrounding streets or their location within the city. The uncritical obtrusion into single-family neighborhood fabric, or the haphazard mushrooming of slabs and towers, represents not only the denial of a coherent urban form and public realm, but the reduction of the very idea of city-making into an unchecked, rapacious capitalism.

- There are two planning tools that have perpetrated this attitude – Floor Space index and Coverage. Floor Space Index (FSI or FAR) establishes the optimum building envelope within a lot per its specific zoning designation. It is expressed as a number: A FSI of 3 means that the total buildable area can be up to thrice the lot area. Coverage in turn establishes the extent of the building footprint on a lot, or the amount of open space to be accommodated within the lot. It is expressed as a percentage of the lot area: A Coverage of 75% means that at least 25% of the total lot area must be open to sky space.

- The idea of “Blending Density” represents a critical counterpoint to this syndrome. It advocates for a heterogeneous distribution of buildings on a lot or block basis. It replaces the homogeneity of FSI-based development with a calculated massing diversity that responds to and evolves from the desired character of its physical context. For instance, the FSI target of a single tower floating within a lot can also be achieved through a combination of a tower and mid-rises within the same lot appropriately massed to respond to their surrounding streets. Likewise, an FSI of a single mid-rise can be recalibrated as a combination of mid-rise and low-rise buildings making the development compatible with adjacent single-family houses.

- Subdivision Standards can in turn help guide the design of large empty sites that are typically developed as introverted enclaves with repetitive building multiplied across the site. For instance, parcels larger than 0.8 hectares (2 acres, or the size of a 100 x 100 meter block), can be required to be broken into smaller development parcels through the introduction of blocks, streets and alleys. Based on the street type they front, appropriate lots can be designed to receive appropriate building types, which combined with the urban standards can generate a conscious neighborhood form and character.

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Transect of North American residential typologies – from the Single-family House to the Tower. A parallel calibration of place-specific types can be generated for other climates, cultures and countries. (Courtesy: Moule & Polyzoides)