Prefabrication experiments - 430 - XL(slabs) - Linear dwelling hives

 

Known simply in architecture as slab blocks, these densely packed, multi-unit edifices are arguably the most iconic template for arranging dwellings articulated to modernism and its sustaining doctrines linked to industrialization: standardization, modularity, repetition. They are symbolized by a sweeping aggregation of flats stacked to form linear, sinuous, and seemingly endless patterns. Characterized by slim double-loaded corridors and the liberated ground plane surrounding them, these monuments shaped a mass-void proportion that completely disrupted classic city planning. Narrow floorplates, associated with slabs, were sometimes also fed by elevated catwalks giving access to single-sided flats. 

 

A normalized floor plan supported by some type of open large-spanning skeletal structural system made it possible to alternate lodging typologies and organizational patterns within the same structural grid. The post and beam, post and slab, or the panel and slab are the most common. Prefabrication and industrialized construction relate to these slabs as design was condensed to expressing an axis onto which dwellings were connected as if conveyed by an assembly line into their permanent position. Modular volumetric, panel systems or a combination of both strategies were used to relate affordability through duplicating regulated types for both dwelling units and normalized components for all other building systems, particularly for elevations.   Le Corbusier’s Unité d’habitation at Marseille (1952) or Marcel Breuer’s ZUP de Sainte-Croix at Bayonne (1968) typify the unit to whole relationship of theses territorial edges standing vertically as monolithic hives dominating extended landscapes.

 

Providing flats at a mass scale attached to common services or amenities communicated the long-standing analogy between large cruise ships of the early twentieth century and the modern slab block buoyantly touching ground, its body filled with ergonomic cells and its rooftops imagined as gardens for leisure. Defined by some modernist architects as open racks onto which manufactured units would simply be inserted foreshadowed megastructures, Japanese modernism’s answer to postwar rebuilds.  Slabs come in a myriad of scopes and scales but all feature an extruded or sweeping shape creating a hedge of dwellings. Alvar Aalto’s Baker House (1949) or even Ralph Erskine’s inhabitable wall proposal for Resolute Bay (1973) demonstrate the vast social and environmental possibilities of these straight or sinuous lines defining urban form. 

Unité d'habitation (top left); ZUP de Sainte-Croix (top right); Baker House (bottom left); Resolute Bay proposal (bottom right)

Prefabrication experiments - 429 - SML(urban blocks) - Wohnregal precast concrete components

 

Providing affordable housing solutions is a deepening problem for contemporary cities. Construction costs are soaring, dense urban form engenders logistic challenges, conventional construction is wasteful and traditional project delivery methods are organizationally messy. Considering these obstacles, it’s increasingly difficult to grasp why offsite construction hasn’t earned a larger portion of new housing starts. Although building construction employs wide-ranging mass-produced components, high levels of integrated systemic design and manufacturing remain elusive. Current crises are potentially inflecting interest in offsite methodologies with all stakeholders understanding the enduring web of nuisances that prefabrication has the potential to address. From efficiency to quality, architects are also rediscovering industrialization concepts for increased performance and to ensure higher quality projects.

 

Historically, architects have generally critiqued prefabrication as either too prescriptive or too rigid. Architectural studio FAR recently designed a six-floor urban block using a kit of precast reinforced concrete components. Wohnregal in Berlin, Germany built in 2019 celebrates a tectonic arrangement of columns, beams and slabs to assemble a warehouse/loft type edifice with large spans conducive to flexible layouts and dwelling patterns; 13-meter spans provide plenty of room for occupants to accommodate their needs. Floor to ceiling glass walls reveal the structure’s manifestly modern roots and the open spans devoid of load-bearing obstacles make it possible for the interior spaces to evolve over time.   The components were dry assembled in six weeks requiring less on-site management and wasteful shuttering that would normally be required for an onsite traditionally cast equivalent structural system. Dry assembly also increases possibilities for long term circularity. 

 

FAR’s proposal aimed to showcase a bridge between customization and industrialization, a subject that continues to be the crux of many architectural and industrial prototypes. Mechanical cores were also used to rationalize systemic distribution and increase flexibility as all adjacent spaces can be subdivided without affecting the overall structural or mechanical layouts. The urban multi-story warehouse archetype has long been associated with flexibility, changing occupants, and even mutating according to evolving functions. While Wohnregal maintains this type of structural openness, its prefab components highlight a symbiotic relationship between architectural form, rationalized structure, reducing costs, quicker construction and potential adaptability, all fundamental elements of any robust housing strategy. 

Wohnregal dry-assembled precast components

Prefabrication experiments - 428 - ML(urban blocks) - Modernist principles and the Yerba Buena Lofts

 

The urban block comprised of different apartment types and shapes organized in a coherent aggregation influences social diversity within collective housing projects. Arranging differentiated relations also presents opportunities to enrich an edifice's appearance by particularizing façades that celebrate or camouflage the tensions between typological organization and their external affirmation. Modern prototypes like Le Corbusier’s Unité d’Habitation mezzanine unit or Mies Van de Rohe’s Lafayette Parks interlocking flats, and even Alvar Aalto’s Hansaviertal Apartments provide iconic examples of intertwining spaces to create dynamic housing patterns. While the three prototypes were not factory produced, their repetitive grids and composing spatial elements feigned an industrialized posture which played into modernism’s serial production narrative. 

 

Contemporary architects still combine and relate these ideas and disciplinary subplots to showcase innovative urban housing strategies. The Yerba Buena Loft units designed by Stanley Saitowitz and Natoma architects in San Fransicso  (2002) employ a mezzanine loft typical flat section along with a thick façade holding loggias or winter garden balconies to shape a crenellated streetscape pattern of masses and voids within a concrete superstructure, betraying their modernist roots. The apartment building’s section bridges front and back streets with double height commercial spaces establishing a pedestrian scale and a central portion of the deep section containing a four-story parking structure. Above this fourth floor, the building is divided into 2 parts: deeper mezzanine units on the south and half depth mezzanine units on the north. Both north and south units use the same principles to organize flexible loft units. The double height loggia spaces relating to Folsom Street side are directly linked to a corresponding interior space where a spiral stair leads to a bedroom open to the lower level. The mezzanine unit sections, and exterior loggias are repeated throughout the block. 

 

Flexibility principles are evident in the ordering of served and service spaces: Wet rooms, kitchens and baths, are concentrated on corridor and demising walls freeing adjacent spaces to varied organizations. The rigorous grid-based concrete structure presents an industrial discourse conveying a dynamic interplay between skin, structure, and interior planning. 

 

Yerba Buena Lofts