Innovative urban housing solutions are constantly evolving with the highly competitive nature of the housing marketplace. The critical housing shortage in many of our most dynamic cities, coupled with the ascendancy of urban living, is driving a need for larger, denser and more amenity-rich housing projects. Everyone wants central locations in walkable neighborhoods, but these are complex endeavors, on complex sites, with many stakeholders. These buildings must provide high-quality living environments for the tenants as well as enhance the surrounding neighborhood.
Internally, these projects sometimes contain unorthodox sizes and mixtures of housing units, with trendy amenities packages, in a high-stakes effort to meet and even predict demographic trends. In addition to housing, they often provide restaurant and retail space and sometimes contain offices and hotels.
Externally, due to their importance in shaping the present and future character of their environs, these projects typically receive close scrutiny from all involved (and those indirectly involved).
Urban housing projects are more design-intensive and closely parsed by the public than ever before. The numerous design challenges that must be addressed demand the participation of highly experienced design professionals who thoroughly understand urban housing and are committed to both the success of their clients and the betterment of the community.
Building Typology: the Wrap, the Podium, the Tower, and the Slab
The first step in designing an urban housing project is proper consideration of building typology. One must weigh low-rise, low-density solutions (the wrap and the podium) versus high-rise, high-density solutions (the tower and the slab).
The Wrap is a low-rise building type that, while achieving significant densities, is best characterized as “urban transitional.” These are primarily located in edge cities, places that are still evolving into truly urban configurations, where land is too expensive to surround buildings with surface parking but cheap enough to rule out subterranean parking structures. Thus, the wrap is an important player in the urbanization of formerly suburban areas.
The Wrap typically comprises four stories of on-grade, Type-5 wood-frame construction surrounding an above-ground, concrete parking structure. The housing and parking buildings are structurally separate, allowing high cost efficiencies in each. The continuous perimeter of four-story housing provides an opportunity to design a residential streetscape that emulates the scale and character of traditional urban side streets while accommodating modern parking requirements.
Despite its simplicity, the wrap can easily achieve densities of 50 to 60 units per acre. In coastal California, and other relatively high-cost markets, its cost of construction ranges from $175 to $225 per rentable square foot (RSF).
The Podium has become an effective player in truly urban situations. It is five stories of Type-3 wood-frame construction on a concrete substructure. In most circumstances, this concrete “podium” comprises one-story above grade, with two or more parking levels below grade. The concrete podium, in addition to containing building lobbies and parking, often contains ground-floor retail space. The longer spans and tall ceilings afforded by concrete construction make it perfectly suited for retail and restaurant tenants, while the top provides a space for outdoor amenities such as pools and gardens. With the entire construction categorized as a low-rise (less than 85 feet in International Building Code jurisdictions), wood-framed construction results in significant cost savings compared with high-rise buildings.
Many jurisdictions allow two stories of concrete construction above grade, for a total of seven stories. As a result, two stories of concrete construction above grade with five stories of wood on top supported by subterranean parking has become the definition of the “mixed user” in many cities.
Some disparage the podium and other low-rise buildings as suburban interlopers into territory best reserved for high-rises; however, buildings of six or seven stories have been the warp and weft of the urban fabric for centuries. Such buildings provide tremendous flexibility of design, fitting into a wide variety of sites and accommodating many unit types while defining and activating the street.
Even with its low-rise status, the podium can achieve densities of 65 to 100 units per acre. In coastal California, its cost of construction ranges from $250 to $300 per RSF.
The Tower is a building type that has recently transformed out of its traditional association with office space. Socioeconomic changes have radically altered that association, and the tower is now recognizable as a building that embodies city living. Tall, slender, and (lately) glassily transparent, towers continue to proliferate in cities throughout the world.
The tower is invariably of Type-1 construction, meaning concrete and/or steel, and access depends exclusively on elevators, exit stairs, ventilation shafts, and other building services. Residential tower floor plates are generally smaller than those of office towers and can range from less than 8,000 square feet to 18,000 square feet or larger, with many in the 12,000- to 15,000-square-foot range.
The fight to achieve maximum efficiency is a major economic factor in tower design. In the most cost-effective towers, elevators, corridors, and exit stairs take up no more than 20% of the floor plate, leaving at least 80% as rentable square footage, which can be difficult to achieve.
Even when efficiently designed, the tower is among the most expensive residential building typologies to build. Given the tower’s cost, difficulties with entitlement, and the densities that can be obtained with the podium, it’s often advisable to do a comparative analysis between the two before proceeding.
The tower can boast densities of 100 units or more per acre. In coastal California, its cost of construction ranges from $325 per RSF and up.
The Slab is a formal variant of the tower. It is also a high-rise, but whereas the tower soars, the slab stretches—more wall-like than needlelike. Slab floor-plate sizes are typically larger than those of towers, often within the 20,000-square-foot range. This arrangement leads to marginally greater efficiencies than with the tower, usually achieving 85% rentable area. Offsetting these efficiencies, the slab often requires greater land area to build, and in urban areas its wall-like form can be especially objectionable, blocking views and casting shadows. Nonetheless, in the right situation, the slab can be an effective form of high-rise housing.
Happiness Is Elusive: Stakeholders and Their Discontent
When it comes to building new urban residences, tension often exists between the needs and desires of individual owners and residents and the larger community’s interests. A community will benefit from a designer who understands the primacy of urban design in shaping urban housing projects. The scale, mass, and character of the surrounding context must be accounted for—and, ideally, enhanced—with the addition of new buildings. Historically, strong overall design, durable construction, and flexibility have been important considerations at street level, as they form the building’s primary interface with the community.
Simultaneously, the needs of the residents, considered from the inside out, are equally as important in determining the project’s success. Timeless considerations for the small details of daily life will transform generic product into far more appealing homes. Orientation, sun, and views can be as important as square footage.
All things considered, when designing an urban residential project, the choices, challenges, and decisions that must be addressed by design professionals are daunting. Experienced professionals will confidently guide their clients through these choices, in a way that assures favorable outcomes for all stakeholders involved.
This article was originally featured on our sister site, MULTIFAMILY EXECUTIVE.