"Under what theology does this work?! Where is the empirical evidence that these street designs make for a better place."Well, there is a similar battle in the architecture field as well. I thought I might cross-post Michael Mehaffy's email to the Professional Urbanist Listserv, where he significantly expands on my riff against tall buildings (well, not so much against, but more as a voice of moderation to the hyper-density crowd -- I'm merely against them as the ONLY solution) to a broader discussion pointing out the obvious flaws (sometimes fatal) in "green" modernism.
Here he is referencing a paper he submitted to a symposium for classicism and sustainability at Notre Dame, and it is quite good:
- Large smooth surfaces. These expanses do not age well over time; small dents and accumulations of dirt detract significantly from the pristine aesthetic at birth. At worst, such structures can become blighted and obsolete, and may have to be torn down prematurely. At best they require frequent, costly and energy-consuming maintenance. Presented to the public realm, they can be exceedingly anti-urban, and disruptive of the pedestrian realm.
- Long unbroken lines, angles and joints. Again, these do not age well and slight imperfections over time show up disproportionately, requiring excessive maintenance and repair -- or, just as bad, suffer a decline in perceived value and appeal. That is clearly not a desirable occurrence when one is seeking sustainability over time. Another potential problem is that the high typical tolerances can be very expensive to produce accurately. A feature that was originally intended to reduce costs (minimalism) can in fact have the opposite effect.
- Glass curtain walls. Even with the most energy-efficient assemblies, the insulation value of these is a fraction of solid assemblies.
- Large-scale, deep-plan buildings. These limit daylight and natural ventilation, sever connections with the outside, and disrupt urban connectivity.
- Large-scale sculptural objects. One key problem is that such structures are difficult to modify and adapt to new uses. This means that obsolescence is more likely if conditions or fashions change not a very ideal strategy if one is seeking resilience and sustainability.
- Tall buildings. Not exclusively a modernist type, but certainly embraced by modernism, they have a number of serious drawbacks: high exposure of exteriors to sun and wind, high ratio of exteriors to common interior walls, tendency to promote heat island effects (which increases cooling demands), inefficient floorplates due to egress requirements, excessive shading of adjacent buildings, undesirable wind effects at ground, high embodied energy in construction, and expensive, high-energy maintenance. Tall residential buildings have also been criticized on social grounds as forming, in effect, vertical gated communities isolated pods that do little to activate the street or energize the larger urban network. While they can provide helpful density, there are more efficient low-rise forms that can deliver suitable densities too.
- Reinforced concrete structures; steel frame structures. Both concrete and steel have high embodied energy and high associated carbon emissions from manufacture. The more exotic modernist structures very tall buildings, very large cantilevers, complex shell structures and the like have a proportionately high reliance on these high-energy materials.
- Limited morphologies of repetition, abstraction, uniformity, and the large scale. Recent cognitive studies have shown that the minimalist form language of modernism, while of interest to other architects and making for dramatic photos in magazines, can be annoying or even stressful to ordinary people going about their daily activities. More research is needed in this area, but there is enough evidence to warrant a much more precautionary approach.
And I discussed the following advantageous features of what may be called "the traditional family of forms and types:"
- Exteriors with articulation, detail and ornament. These features can hide dirt and wear, and actually improve in appearance with time. They also seem to make important contributions to pedestrian scale and interest, which is necessary if we want to create a functional pedestrian environment and a healthy public realm.
- Complex relation of interior and exterior. The oft-maligned front porch and picket fence actually play sophisticated roles in creating connective layers of private and public, a kind of membrane system spanning between the innermost private spaces of a building, and the most public realms outside. The same is true for galleries, arcades, stoops, colonnades, balconies and other traditional types.
- Focus of the building on its public realm. Most buildings prior to 1920 paid close attention to the way they addressed the public realm, with legible entries and ornamental details addressing urban space. These strengthened the relation of the building to its urban context, and strengthened the pedestrian realm around the building a critical need for a low-carbon neighborhood.
- Punched windows. As many have noted, such assemblies reduce the amount of glazing and make it easier to achieve an energy-efficient wall assembly.
- Low-energy, locally adaptable materials. Often traditional buildings have used locally available materials that have not required extensive industrial processing. Wood, for example, was relatively easy to work, and served to capture carbon. Even brick was usually quarried from local clay sources, and fired nearby with relatively modest energy requirements. These materials also made repair and modification easy and efficient, resulting in resilient and long-lasting buildings.
- Thermal mass. Many traditional typologies have used relatively thick wall sections, which allowed for efficient moderation of temperatures.
- Biophilic geometries. This fascinating area of recent research seems to show that for optimum health, human beings need to experience the geometries of nature within their built environments on a daily basis. These include the obvious natural elements like plants, sun and fresh air. But they also seem to include geometries that are characteristic of biological structures, including fractal scales, hierarchical groupings, characteristic proportions, roughness and texture, an optimum mix of unity and variety, spatial layering, a sense of prospect and refuge, and related geometries. Intriguingly, many historic buildings demonstrated rich aggregates of these characteristics. There is reason to believe they may have played a role in the care these buildings received, and their durability their sustainability over time.