A beautiful and successful urban district is a consequence of the conceptualization, design, implementation, activation, and operation. As architects, our role is most specifically upon the design, although we may be involved in all of the steps. There are a handful of basic concepts and strategies, and a handful of choices in each set of concepts. I believe a good designer is aware of what he or she is doing and makes justified decisions.
Urban form is largely a matter of the plan showing paths, nodes, and masses. Review of cities throughout history shows a handful of forms.
- Grid. Paths are arranged in two orthogonal series. Much of the United States makes use of grids. The form dates back at least to Greek and Roman colonies. Grids are often oriented to the cardinal points of north, south, east, and west. Manhattan, New Orleans, Chicago, Bryan, Northgate, Houston, Dallas, are all based on grids. Often there are multiple grids that collide. The edges between the grids can be significant.
- Meander. This form is almost opposite of a grid. The paths curve to account for topography and features. Medieval cities are often based on the meander form as the city has grown from pedestrian and livestock paths. Sometimes a walled city combines the meander form with concentric rings that radiate from a circular or blob-shaped defensive wall.
- Garden. Within a gridded superblock, the paths and roads meander and form cul-de-sacs. Much of south College Station is based on the garden form.
- Double grid. A diagonal grid is laid over a rectangular grid. Washington DC is a notable example.
- Tartan grid. Two or more rectangular grids are overlaid. This can result in a grid of major avenues and a grid of minor streets. More interestingly is the grid of Savannah, Georgia, which has a grid of public squares overlaid on a grid of streets.
- Hybrid. Many cities combine multiple forms, often as a result of growing to overtake neighboring villages or expanding on the edge with new suburbs.
I define urban scale as largely related to the size of the buildings and the open spaces.
- Low rise. One to two story buildings provide a pedestrian scale and tendency toward walkability, but can result in inadequate density to support either economic viability or a walkable environment. The French Quarter of New Orleans is a beautiful example that has also been emulated at Seaside.
- Mid-rise. Three to five story buildings. This is probably the most walkable scale. It achieves enough density to support the necessary businesses and functions within a reasonable distance yet allows for air and light to reach the street. Century Square adopted this strategy. Much of Manhattan, such as Greenwich Village, Brooklyn, Queens, Haarlem, is actually this mid-rise form. London, Amsterdam, Rome, Florence, Venice, and most large cities in Europe are this scale.
- High rise. More than five stories. The buildings at this scale begin to transform into towns and neighborhoods themselves. The vertical routes are often more important than the horizontal routes. The street scene can seem threatening and dominating and the population density can lead to an over-abundance of strangers. Parking and automobile transportation takes on a dominating consideration that can crowd out the pedestrian environment. The Post Oak/ Galleria area of Houston shows how, even with good design, the pedestrian environment is almost impossible to maintain. Downtown Houston and downtown Dallas are other examples.
- Hybrid. The scales can be combined carefully and judiciously to create complex and beautiful forms. Considered as a unit of 200,000 people, most cities have high-rise at the center, mid-rise in the surrounding area, and low-rise in the suburbs.
Density is defined by the proportion of building height and size to streets and parks.
- High. Streets are proportionally narrow compared to height of buildings. Medieval cities, mega-cities such as Cairo, Ciudad Mexico, Tokyo and others often sacrifice transportation convenience for greater density. Often buildings take on a courtyard form where light and air is unavailable on the narrow streets but is available within the block defined by the streets.
- Medium. Streets are moderately wide compared to height of buildings. Many urban designers suggest that a one-to-one ratio of street width to building height is most pleasing and comfortable.
- Low. Streets are broad compared to height of buildings. The street loses definition as a room and becomes a park. This can be attractive, such as the Ramblas or St. Charles Avenue in New Orleans, but it can also become a pedestrian barrier that lengthens paths to the point of making walking impractical. In very cold or very hot environments, a wide expanse of open space is unappealing.
- Hybrid. A city can provide a variety of forms. Different densities can define edges and districts. A street can be punctuated with parks or variations from its norm to define a landmark.
An urban district can be characterized by buildings of a formal type. Basic strategies for buildings in a city include the following:
- Pavilion. Buildings are surrounded by lawn or parking. This is the predominant American form. I think it relates back to the neo-classicism that was the predominant architectural and urban style of the 18th century when the United States was founded. We aspire to the ideal of a Palladian villa, a free-standing monumental building commanding its surrounding farm, plantation, estate, or homestead. The pavilion is an expression of individualism and even anti-communalism.
- Staccato. Tenant units or functions are separated into duplicated but separate buildings. This is also an American form in that our cities are built relatively quickly with a strategy of “sub-dividing” a rural estate. Maximum efficiency and profit may sometimes be achieved by small lots with identical houses. While the form seems unappealing, it often becomes beautiful over the passage of time as individual owners alter, customize, and tailor the identical units into personal expressions. The repetition gives order, pattern, and a sense of egalitarian community.
- Continuous. Tenancies are separated by party walls. This distinctly urban form best accommodates apartments, townhouses, flats, and strategies to achieve density. London makes use of these “terrace” structures to accommodate almost any function, including homes, commercial enterprises, offices, and even small factories.
- Hybrid. Variety can be enriching and can provide a diversity of market choices.
The facade of the buildings determines the public character of the place. Often, regulation is directed at conforming the facade to a set of norms. The facade thus belongs to the public, while the interior of the building belongs to the resident.
- Individualistic. Each tenancy has an individual expression. This approach relies heavily upon the enlightenment of the owner and the talent of the designer. There are few constraints on what can be built in terms of scale, material, proportion, style, color. While it seems at first thought that this approach will lead to richness and excitement, it can often lead to dullness and a cacophony.
- Uniform. Each tenancy has the same expression. Sometimes this is achieved because a developer and architect design the uniform expression, or it can also be achieved through regulation. At first thought, this approach can seem dull and boring, there is a tendency for it to assume a greater degree of individuality and richness through time.
- Hybrid. Old cities accumulate buildings from different times with different construction methods and different styles. A graceful norm can be very beautiful when complemented by exceptions to define landmarks.
An urban district often has a unified style that records the time n which the city was built.Here are some styles that I have observed in cities.
- Vernacular. The buildings are constructed in straightforward way
- Defensive. Characterized by heavy, tall walls, crenellations, small windows, simple forms.
- Classical. Based on Greco-Roman forms.
- Romanesque/gothic. Characterized by tall forms, arched openings, simple primary forms with accretions, steeply pitched roofs, stone and heavy construction.
- Renaissance. Employs classical motifs, largely derived from Roman architecture, including collonades, pilasters, symmetry, pediments, piano terra and piano nobile, rectangular windows.
- Neo-classical. Employs severe compositions using Greek orders.
- Georgian. The dominant traditional American style is derived from 17th and 18th century British architecture of the time of King George. It is characterized by brick or stone walls, pitched roofs, double-hung windows with cross or grid window panes, restrained Renaissance detailing and proportions.
- Beaux-Arts. Employs a mixture of historical styles linked to building use.
- Southwestern. Adobe walls, exposed rafters, rough-hewn wood.
- Arts and crafts. Heavy timber, exposed structure, wood finishes, tile, inventive ornament.
- Le Corbusian. Adopts the five points of modern architecture. Richard Meier’s designs are probably the most exemplary. A Cartesian Modernist syle.
- Miesian. Adopts the curtain wall and universal space ideas of Mies. Chicago high rise architecture is exemplary. A Cartesian Modernist style
- Plastic modern. Makes use of non-rectilinear geometries.
- Other. Asian, various vernacular styles, non-European originated.
- Hybrid. Combining styles can lead to a kitsch and pastiche that is often disagreeable. More subtle references and allusions can help a building in one style connect to buildings in another style while retaining a stylistic integrity.