Designing Successful Neighborhood Squares. Part 6. Surrounding building heights/proportions

By Suzanne H. Crowhurst Lennard

“In ancient times… public squares, or plazas, were… of prime necessity, for they were theaters for the principal scenes of public life.”  Camillo Sitte[1].

“… there must be open spaces that provide a fitting stage for the drama of daily life.” August Heckscher[2].

Lively social life in the community requires a public place open to all that serves as stage and theater for actors and audience[3].

Proportions:

The proportions of a square are critical to how comfortable we feel in the space. As Kidder Smith and many others have observed, beloved piazzas and squares feel like a well-proportioned room, theater, or a grand hall. Jan Gehl’s observations[4] indicate that the design of a successful neighborhood square has far more to do with designing a theater than with architecture per se.

Angle of vision (Gehl)

The Golden Rule in achieving satisfactory proportions in the relationship of building heights to size of square is rooted in human physiology. When standing in the center of a square we feel comfortable when we are surrounded by buildings that are within our normal angle of vision, with a clear view of the sky above the buildings.

However, there needs to be not merely one spot, but an area near the center of the square where a group of people may gather, face and talk with one another, and where each person sees a little sky above the building they are facing. This “sky-view island” should be at least 20’ x 20’, or 20’ x 40’ in a rectangular square.

Our angle of vision is 50° – 55° above the horizontal[5].  Thus, when we stand at the edge of the “sky-view island” in a 100’ x 100’ square, we feel more comfortable when the surrounding buildings are no higher than 50° above the horizontal, i.e. 48'.

This can be mathematically figured using the following formula: distance from the “sky-view island” x tangent of 50 degrees, i.e. 40’ x tan 50 degrees = 48’. 

In a rectangular square of 100’ x 200’, with an “sky-view island” of 20’ x 50’, buildings at the narrower ends can be up to 89’ without causing claustrophobia, i.e. 90 x tan 50 degrees = 89’.

Sight lines

The exception to height is in the case of a slender tower that plays an important civic or religious role in the community. Traditionally, Italian piazzas and campi have been marked by a tall church campanile, identifying the center of the community from afar and providing a beacon for those approaching on foot. In the Middle Ages, Bruges took the same symbol of the bell tower to mark the new center of the community, the town hall which was built on the market place.

The sense of drama inherent in public life may be heightened by a dominant building that acts as a theatrical backdrop. The civic or religious character of such a building imparts an identity to the space and exerts a subtle influence on life in the square.[6] It may be argued that a particularly beautiful façade of a civic or religious building can appropriately rise above our sight line, causing the viewer to crane her head to appreciate the sight. Such a building might appropriately offer a theatrical “backdrop” for civic and religious events on the square, or for commemorative photographs.

Surrounding buildings should not be so high that the proportions of the square resemble a canyon. We are not talking here about providing “pocket parks” in a heavily overbuilt city – the monumental task that Holly Whyte[7] undertook in the 1970s. In New York, the lack of well designed public places where office workers, shop assistants and CEOs could eat lunch outside, led him to help structure a bargain with developers that offered developers extra height for their towers in exchange for a pocket park – a bargain which he later recognized led to all too few really well-designed and truly public places[8]. The best pocket parks (e.g. Paley Park) are beautiful niches that facilitate some social interaction among strangers at lunchtime. They are not neighborhood squares frequented by the local community throughout the day and into the night, generating community networks – the goal that we are examining here.

Social field of vision (Gehl)

Maximum horizontal dimensions

A successful neighborhood square should be proportioned in such a way that it is possible to easily recognize someone across the narrower dimension of the square. At a distance of 150’, clothing, gait and general behavior can be recognized, allowing people to identify someone they know, and wave. Facial expression and emotion can be perceived at 115 feet, which, as Gehl points out, happens to be the distance from the stage to the top balcony in an opera house. This distance allows a more reliable assumption as to the other person’s readiness to engage in conversation. This also suggests that, to ensure the square is safe, by providing “eyes on the square”, all parts of the square should be within 115 feet of some surrounding dwellings.

The larger horizontal dimension of the square should not be larger than 300’ without being divided into sections. This is about the distance at which we can see a figure in motion[9]. We can tell if the person is sitting, standing, walking, or running. Our brains instinctually interpret movement in the field of vision as information relating to the safety of a space, possibly triggering us also to “flee” or to take a seat and relax.

Beyond 300’, we cannot gather enough information about people to know whether they are friend or foe, and this lack of information can be disquieting. It puts us at a disadvantage, and makes us rely more on how other people closer to us are acting. The effects of this scale dimension are observable in mass mob behavior, and were deliberately manipulated by dictatorships in events such as the Nazi rallies.

Human scale:

Kidder Smith showed us how “an architectural and urban setting can be created that breathes and pulsates with a very human feeling and very human scale”^[10].  Surrounding buildings are scaled to human proportions and human use. Windows and balconies provide a visible human presence that allows residents to identify with the square, and that, by providing “eyes on the square”, ensures the square’s safety.

Communicating with people on the square

It is important for all residents in surrounding buildings to feel connected to life on the square, to feel a sense of ownership and jurisdiction over activity there. For this to happen, they must be able to hail a friend on the square, and identify potential troublemakers. Within a distance of 50 to 60 feet (4 to 5 stories) a conversation is possible without shouting[11]. At the 6^th floor one can wave, but a conversation is not realistic. Above the 6^th floor residents are too far from the square to feel connected to it or able to interact with it, and therefore are less invested in the square.

Hertie department store, Münsterplatz, Bonn

Small-scale buildings reflecting varied activities, needs and styles convey the variety and diversity of human society. A square surrounded by blank walls and inhuman scale buildings will be unloved and shunned by its citizens. Citizens of Bonn, Germany complained bitterly when a concrete and glass Hertie department store was built on Münsterplatz. When a competing department store on the opposite side of the square constructed a building with windows and a pitched roof reflecting the beloved traditional Bonn architecture, Hertie was finally convinced to remodel their façade.

Competing department store, Münsterplatz, Bonn.

 

 

 

 

 

Turn to: Part 7. Facades, setbacks and stepbacks