Chapter 5. MASSING AND STREET WALL  

A. MASSING

The street is often described by urban designers as "a large outdoor room." The opportunity to shape this room exists on every street, as its shape is defined by the primary façades of its buildings, which create a street wall.

Reducing large floor plates and varying a building's height through the creation of smaller structures or façades is a valuable concept when designing large projects that consume half a block or more. Sculpting a building's mass can also help avoid large bulky structures, which provide more visual monotony than variety. It is the well-balanced variety of building massing and textures of shadow, light and materials that in total adds to the richness of downtown's built environment.

Figures 5.1 through 5.4 illustrate various residential densities ranging from low-rise residential to high-rise residential massing and low-rise commercial massing diagrams. Buildings are generally defined by three types of massing. Low-rise massing is generally less than 6-story structures as seen in Figure 5.1. Figure 5.2 illustrates Mid-rise massing at seven (7) to 20 stories and typically 12 to 20 stories. Fig 5.3 illustrates High-rise massing that is more than 20 stories. Figure 5.4 illustrates how a low-rise commercial building height ranging between 70 feet to 85 feet incorporating a mix of uses. Parking is usually located in a structured facility behind (attached or detached) the mixed use building, or beneath the building footprint.

Design building massing to reinforce the street wall with well-scaled elements or structures that are sensitive to the neighborhood context.

1.

Divide large building facades into a series of appropriately scaled modules so that no building segment is more than 100 feet in length. Provide a passageway at least every 20 feet wide between buildings. Consider dividing a larger building into "modules" that are similar in scale.

2.

Monolithic slab-like structures that wall off views and overshadow the surrounding neighborhood are discouraged.

3.

A new building should incorporate design elements that provide a base, middle and a top.

4.

A new building should, to the extent possible, maintain the alignment of horizontal elements along the block.

5.

Floor-to-floor heights should appear to be similar to those seen in the area, particularly the window fenestration.

B. STREET WALL

In order to support a pedestrian-oriented public realm, retail or commercial streets would be framed by buildings uniformly placed at the sidewalk with no setback, as seen in Figure 5.5. The height of the street-wall is an important element in shaping the character of the public realm.

Design building walls along the sidewalk (Street Walls) to define the street and to provide a comfortable scale for pedestrians.

1.

Street walls should be located against the back of sidewalk as seen in Figure 5.5.

2.

Walls above the ground floor that step back from the ground floor street wall are considered to be part of the street wall.

3.

Breaks in the street wall should be limited to those necessary to accommodate pedestrian pass-throughs, public plazas, entry forecourts, permitted vehicular access driveways, and hotel drop-offs.

4.

An identifiable break should be provided between a building's retail floors (ground level and, in some cases, second and third floors) and upper floors. This break may consist of a change in material, change in fenestration, or similar means as seen in Figure 5.6.

5.

Vertical breaks should also be taken into account with fenestration, such as columns or bays.

6.

When a property is situated in such a manner as to appear to be the terminus at the end of a street or at a prominent curve in the river, buildings should incorporate an architectural feature that will provide a focal point at the end of the view. These features may include:

a.

Enhanced building façade

b.

Enhanced garden or landscape in an open space

c.

Variation in roof shape

d.

Change material and color

e.

Tower element

C. HIGH RISE TOWER SPACING

Towers ought to be spaced to provide privacy, natural light and air, as well as to contribute to an attractive downtown skyline.

Establish the building form and massing that responds to function, site characteristics, the context, and the type and mix of uses -regardless of stylistic approaches. A high-rise building has three primary components or areas of interest that are integrated into the whole of the design: a base or podium; middle or tower, and a top. The base is the primary interface with the city context and its street, people, and services. The tower is sized, shaped, oriented and clad to respond to functional and contextual requirements, as well as the lifestyle of the residents. The top integrates mechanical equipment, and contributes to sky views.

The diagrams below illustrate several common types of tower forms and how the street wall is defined for each. A tower consists of ground floor retail and parking or habitable space above. Towers should have a minimum four (4) story street wall height . A lower street wall can occur on a narrow two lane street, while a higher street wall may be appropriate on a four to six lane street.

Tower Massing

Towers in downtown San Antonio greatly affect the appearance of the overall skyline. Evaluations in other cities suggest that towers are most attractive when they have a ratio of height to width of about 3.5:1, for example, 100 feet wide and 350 feet tall. Reducing the bulk of the top of a tower ("sculpting" the tower) can make it more attractive.

Towers ought to have slender massing and sound proportions.

1.

Towers should have their massing designed to reduce overall bulk and to appear slender as they ascend higher.

2.

Towers may extend directly up from the property line at the street and are not required to be setback.

3.

Tower siting and massing should maintain key views toward important natural or man-made features.

4.

Design the middle segment or tower of the building to break up the overall bulk into smaller segments and address impacts such as shadowing and views. Reduce the perception of mass through architectural detailing such as changes of materials and color.

5.

Design the top of buildings to be a 'fifth façade' that may be distinctive against the skyline when looked up to or viewed from above. A well-designed roofline creates opportunities for sky views and views to distinctive landmarks; creates opportunities for sunlight to reach the ground, and orients the public when way finding.

6.

Design the top of the building and/or the top of its podium to include opportunity for communal outdoor amenity space and/or a place for environmental innovation such as green roofs, rainwater recovery and solar panels.

Tower Form

Tower forms ought to appear simple yet elegant, and add a sculptural form to the Downtown San Antonio's skyline.

7.

Towers should be designed to achieve a simple faceted geometry and large vertical plane movement. They should not appear overwrought or to have over-manipulated elements.

8.

Towers that emulate a more streamline modern style should provide variety through subtle details in the curtain wall, and the articulation of a human-scaled base at the street level.

9.

If a project has more than one tower, they should be complementary to each other and employ the same architectural design approach.

10.

Generally, buildings over 150 feet tall should not be historicized. They should represent contemporary interventions in the skyline.

11.

A tower's primary building entrances should be designed at a scale appropriate to the overall size and design of the tower and be clearly marked.

12.

A building's top should be delineated with a change of detail and meet the sky with a thinner form, or tapered point. Unarticulated, flat-topped buildings are not desired in downtown San Antonio's skyline.

13.

Mechanical penthouses should be integrated into the tower design and should not appear as a separate element, as shown in Figure 5.7.