In the past, in a less densely populated urban context, houses and buildings were built with a direct connection to the street, with no need for walls and front fences. Over time, the urban fabric was transformed, and the division between public and private spaces became increasingly evident and — under the argument of public safety — necessary. Although this division occurs in different ways in Brazilian cities, in general, walls, fences and railings are used on the facades, creating a transitional space between the building and the street, transforming the relationship between them.
The high masonry walls are one of the security elements used in condominiums, houses and buildings to guarantee the security of their space. The consequences of these walls are inanimate, deserted façades and streets and public spaces. These consequences were much questioned by theorists at the end of the 20th century and the beginning of the 21st. In contrast to this type of experience in the city, many city halls began to change their legislation seeking to build alternatives for the urban fabric. The active façade is retaken and, with it, a new variety of fences.
Although conceptually the idea remains the same – to establish a clear limit between what is public and what is private – the materiality of this limit depends on some factors. Local legislation, the intended ambiance (inside the lot and on the street), privacy requirements, economic issues and maintenance, resistance and durability can interfere. A metal fence with plants or even glass can be used as an alternative if closed and opaque walls are not possible.
On the one hand, the metal railing has a wide variety of shapes. They can be made of bent sheets, rebars and gratings, besides being able to be used with plants, which can bring more privacy between the street and the building. On the other hand, steel is a material that varies in cost, which impacts the final price. In recent years, steel prices have risen, which has made a good part of civil construction seek alternatives for its use. In addition, its maintenance is costly and requires regular painting to protect the material from exposure to the weather.
Increasingly, glass is being used as an alternative because although it is not self-supporting – making it necessary to use an adjunct structure such as aluminum profiles – it is a material that can pay off financially. With the advancement in its technology, glass became resistant to impacts. It can also be reinforced, becoming useful for internal security. Its visual permeability is also interesting if there is a need for communication between the street and the building, in mixed-use buildings, for example.
Since glass can be exposed to the weather even without treatment, it requires simple and less frequent maintenance than fences and grades. Finally, after cultural changes, the aesthetics of glass, its transparency and fluidity, have been increasingly valued in our society. Contemporary skyscrapers and their glass facades, together with the industrialization of construction, have transformed society's aesthetic sense. Before, iron railings designed and made manually by craftsmen were valued. Today, the emphasis is on industrialization and the optimization of materials and elements.
Thus, while there is a cultural change in the appreciation of constructive elements that impact social preferences, there are also economic and maintenance issues that contribute to it. Still, the points raised by Jane Jacobs remain valid for our urban context. Even if, hypothetically, walls are completely removed, it is necessary to reframe our relationship with the street, with what is public, so that we can transform our social relationships.
