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

Prefabrication experiments - 427 - ML(urban block) - Modular reconstruction with Speedstac

 

The serial urban block symbolized 20th century prefabrication and industrialized construction. Framed by normalized government intervention using panelized or modular volumetric construction, planning logistics, zoning, arrangements, materials, and systems were all optimally coordinated from procurement to site installation. In the USSR in particular, the pattern buildings’ production was centralized; factories were set up and neighborhoods were completely built by national and local Gosstroys (state committees for construction) deploying similar design and construction methodologies geared toward efficient production. 

 

Since these buildings shared details, dimensions, performance criteria and components, they have also aged analogously and are susceptible to similar degradations. Sixty to seventy years after their initial commissioning some have either been demolished or most are in dire need of functional updates, repair, maintenance and in some cases, new conflicts that have destroyed parts of the structures. As the buildings share similar characteristics, their upkeep, renovation, or even restoration can lead to a form of standardized formula applied to their composing parts. 

 

The Speedstac^tm, an offsite manufactured retrofit unit made up of Integrated Structural Panels designed by architectural firm WZMH architects, proposes an industrialized building system for refurbishing or reconstructing parts of K buildings damaged by the Ukraine Russia conflict. The K acknowledges the Krushchyovka, nine story buildings produced by the USSR during the cold war. Arranged in the form of containers, the strategy could prove to be an efficient platform geared for adaptive reuse and recommissioning the typical prefab block. Contrary to the original systems, Speedstac uses high performance construction for both thermal and acoustic comfort.  The modular units’ panels include all necessary amenities, systems and function like a plug-in prosthesis for either parts of a building or for complete rebuilds. Planned in the context of the current crisis, the boxes could feasibly be used in any flat slab concrete structure stripped of its outdated services and envelopes to act as a support framework. The factory completed containers would simply slide into the structure.  

 

Produced for quick installation this type of functional unit could also be used for adapting existing commercial buildings as an affordable housing solution in cities with an aging building stock. 

Prefabrication experiments - 426 - SML(urban blocks) - Tenements and industrialization

 

Planning dwellings vertically around a common circulation core is symbolic of 19th century urbanization.  The urban block of flats is a fundamental component of the modern city. Characterized by repeating flats stacked 4-6 stories high, this type evolved and guided the development of emblematic localized patterns: tenements, in New York rose out the rapid urbanization of the city. Their organizations were based on a centralized stair well and sometimes a series of lifts giving access to each floor plate. The New York tenements built on 25 foot by 100 feet parcels divided for high density, allocated industrialized city form. Urban blocks have remained consistent and are both an affordable and sustainable strategies for housing provision. 

 

Offsite construction can be leveraged toward the urban block as dense housing has an engrained repeatability in spatial organizations, systems, amenities and interior functional elements such as rooms, baths and kitchens. Independent of any industrialized building strategy, rationality and frugality were the keys to the speculation that spawned these housing solutions. The typical floor plate layout is an example of standardization applied to housing design. Each unit could then be constructed from similar potentially mass-produced components.

 

Today’s affordable housing crises and the continuing urbanization of populations tends to both reviving the collective housing block and industrialized building strategies. From stacking reinforced concrete modules at Habitat 67 to the precast panelized blocks built throughout Europe in the aftermath of World War 2, prefabrication was used to invent and develop the collective housing typologies of the 20th century harnessing principles of bulk procurement and centralized logistics. Still, while stacking similar flats and floorplates lends itself to prefabrication, it has been marginally applied as each edifice in a series is usually built as a prototype. The postwar Eastern European socialist model deploying the pattern urban block repeating the same building systems and designs from context to context spearheaded a vision of industrialization underwritten by political choices; this model seems to be the only way of achieving the mass-scale application of offsite construction in collective housing supply.   

Prefabrication experiments - 425 - SMLXL(row-houses) - Interlocking modular dwellings

 

Industrialized housing solutions can display imaginative assemblies projecting homes in many variations. Stacked, aligned, interlocked or juxtaposed modular volumetric dwelling proposals employ densely packed or clustered organizations to rationalize building footprint, infrastructure provision and service distribution. Aggregating spaces and volumes in hive-like structures and arrangements using container-like prisms is the most common strategy. The manufactured units are completed before delivery and setting, a streamlined supply chain from planning to factory to site includes overwhelming advantages in terms of project timelines. Architectural singularity is perhaps the biggest challenge for modular volumetric’s rational stacking. 

 

A recent project for student accommodations by Dyson Industries displays a unique silhouette with normalized factory finished boxes. Each Cross laminated timber box is connected to supporting or adjacent units to shape a 6-unit agglomeration. Designed by WilkinsonEyre architects, a London based firm, the «modular village» is based on rigorously dimensioned and designed giant building blocks structured in CLT and clad in Aluminum. The boxes are massed in a unique volume with each recognizable box cantilevered or setback to achieve differentiated form from simple prisms. 

 

Even more complex organizations of interlocking modules have been explored leveraging geometries toward extreme compactness. Architect Liu Lubin's proposal for adaptable micro houses develops a modular composition from functional ergonomic sections, representing human postures and activities, resting, standing, sitting etc. The cross-shaped modular blocks can be matched and linked into micro-dwellings or larger mat-like collective housing blocks. Each cross-shaped unit is planned on a 600 mm grid within an overall dimension of 2,4m wide by 2,1 m deep. The stackable, enclosed, scalable, rotatable object envisions domesticity and its forms as changeable. A fibre-reinforced foam core composite makes it possible to easily lift and move the modules while achieving a smooth white ascetic surface inside and out. A comprehensively manufacturable product including factory finished doors and windows along with built-ins meticulously drawn-up to provide interior functionality, Lubin's vision deploys similar concepts used by Japanese Metabolists plugging dwellings together to establish novel forms of urbanity; shaping intense living environments that are determined by human form - a type of anthropomorphic collectivity.

Liu Lubin's cross-shaped modular volumetric proposal

Prefabrication experiments - 424 - ML(mat-building) - Fredenborg Houses

 

A proliferation of row-houses in multiple directions, the mat-building concept has been applied to low-rise, hi-density housing in varied types, scopes and scales; all share fundamental principles including compact rational plans, shared party walls, grid configurations, standardized constellations and common building methods. Some twentieth century prototypes also explored an ideal of adaptability or even expandability; modular arrangements could be composed in response to varying landscapes, evolving functional requirements determined by an entrenched systemic capacity to add units, organically breeding neighborhood fields.

 

System building, adaptability and modularity seem to go hand in hand, and their underlying approaches were posited by three generations of modernist architects from Walter Gropius’ expandable house system to Cedric Price’s steel houses and as seen in the last post, Steven Holl’s Dense Pack Dwellings. The creative association of building elements with harmonized volumes to achieve uniquely industrializable forms, at least in narrative, informed flexible carpets of territorial expanses. Their adaptability also pointed to enabling users to interact, design and construct their own environments. 

 

Danish architect Jørn Utzon, best known for the Sydeny Opera house, also explored affordable housing through modular, adaptable organizational systems. His proposal for the Expansiva Byg A/S building kit system was sold by local timber builders and marketed as flexible, adaptable and expandable. The modular components were standardized for repetitive detailing and for maximum user involvement in their assembly.  The basic post and beam structure with a shed roof was completed with panels for walls, roofs and normalized openings regulated for the overall modular scheme. Employed for Utzon’s Fredensborg Houses (1959–1963) described as flowers on the branch of a cherry tree, the archetype outlined a clustered planning of housing units surrounding collective courtyards accessible from public walkways inserted in the spaces between units all leading to a centralized public square. The link between modern grid principles and classical urban concepts were united to shape a field of dynamic dwelling spaces. Built as individualized patio houses anchored to site topography, each unit was placed according to ideal conditions for views, daylighting and shelter from prevailing winds. 

Expansive Byg A/S building system by Jørn Utzon

 

Prefabrication experiments - 423 - MLXL (row-houses) - Mat-building - Dense Pack Village

 

Organizational systems conceived for affordable housing are in a sense related to the same efficiencies required for profitable industrial production: Standardization, repetition, and scalability can all lead to both affordability and profitability. These same concepts are intrinsic to urbanized structure. Strict geometries, grids and modular massing are the building tools of urban planning. 

 

The townhouse, the row-house and terraced housing are great examples of affordable housing theories fused with widespread building culture deployed toward inhabited city blocks. Spaces can be further densely packed from linear geometries common to cities into an intricate geometric weaving of public and private areas massed in a thick field referred to as mat building.  In a compact interconnectedness dwellings or other functions are laid out within the quilt-like patchwork repeating the same composition clusters in a planar field one or two stories high. The term was first used by Alison Smithson in 1974. Architect and author, her article How to Recognise and Read Mat-Building described and analyzed the potential of this modern as well as vernacular architectural archetype. 

 

The mat is a horizontal matrix where grid informs both units and structure. Steven Holl's Dense Pack Village proposition for Haiti experimented with the idea of an inclined mat-building using inclination as a site anchoring device. Imbedded in the existing topography and envisioned as a terraced landscape where each unit would receive equivalent light and spatial qualities, the mat formula is a decidedly democratic urban form; virtues outlined for one basic kernel are multiplied in a highly rationalized manner.

 

Developed in the aftermath of the devastating 2010 earthquakes, the Dense Pack uses a diagonally divided square grid to fashion a mass / void relationship in its basic courtyard housing prototype. Each is then aligned, juxtaposed and multiplied to form an inclusive sheltering earthwork. The inclined plane is supported by a service space running parallel to each house. The square inhabitable earthwork optimizes solar shading, natural ventilation, thermal mass, and grey water recycling to reduce the building’s ecological footprint and to demonstrate a model of housing form harmonized with its sloping setting.

Mat-building Steven Holl's Dense Pack Village

Prefabrication experiments - 422 - ML(row-houses) - Modular infill dwellings

 

The townhouse is arguably the most appropriate housing type to adjust for prefabrication. Tracts are apportioned into aligned lots with similar dimensions and organizing principles. Based on repeating these patterns, coherent streets of townhouses iconically represent dense city dwelling without the sameness of housing blocks and bars connoted with 20^th century mass housing attitudes. Construction techniques are also shared among neighboring units, each portion, part of an open-air assembly line, using the same processes, materials and industrialized parts; The balloon and platform timber fames spanned from one party wall to another supported stacked stories, flats and made it possible to build a plethora of workforce housing blocks in evolving modern cities. 

 

Today many of these emblematic city blocks are still standing, restored and being updated with infill replacements. These infill dwellings are conducive to rationalizing construction as some elements can be repeated over multiple project settings: dimensions, heights, materials, organizations. Module, a creative modular housing company from Pittsburgh, Pennsylvania, USA has made this type of infill dwelling their sustaining business model. While typologically different from party wall developments, similar site parameters are scaled to deploy a modular volumetric platform for zero-energy ready townhouses. The factory produced boxes can be stacked two to three stories high. 

 

Like most modular companies attempting to showcase a successful industrial process for greater productivity and affordability, the company offers an all-in-one shop from design to fabrication to construction with some adaptable townhouse models even evolving from 2 to 3 floors over time, based on fundamental core-house principles. Catalogued on-line, engineered-to-order boxes are produced in the factory while foundations and services are completed on site. Boxes are then delivered and anchored to site foundations, reducing schedule length and maximizing offsite quality control. The infill patterns also simply the procurement process as multiple townhouses can be manufactured simultaneously with the same production parameters. Using contemporary 3d modelling, virtual design and construction, performance can also be monitored over time taking control of design, fabrication, delivery and operational aspects of the home to further optimize the houses’ lifecycle and durability. 

Module's Infill prototypes

Prefabrication experiments - 421 - ML(row houses) - The town house as an urban archetype

 

Urban dwellings feature the potential of densely packed zoning to increase affordability, livability, socialization, and infrastructure sharing, all pillars of sustainable cities. Their narrow frontage inscribed within a rhythmic alignment transforms the detached villa's enfilade of rooms and spaces into vertical organizations articulated to a staircase; different stairwell locations lead to various configurations. Treatises and pattern books have defined some fundamental principles: The American House Carpenter (R.G. Hatfield, 1852) illustrated construction systems and possible patterns for designing row houses found in every North American city. Montreal’s triplexes, New York’s Brownstones, Philadelphia’s rows are just three examples of how stacking floors around flight of stairs can become a centerpiece of urbanity. 

 

Typically, three or four floor arrangements are inset between party walls built along property lines to keep fire from spreading among juxtaposed units. These extending firewalls came to represent fireproofing requirements applied to medieval cities. The width of a standard city lot by a variable depth, spaces like living rooms and bedrooms are placed on either side of core spaces to benefit from natural light. The dual-exposed living areas contribute to a feeling of spatial opulence in an otherwise slim floor plate.  A multiple-floor sequence could be managed to suit multiple tenure scenarios: owner-occupied on all floors, one or two floors rented out as flats, and these even changing over time.  Seen as a prototype for efficient urban living, the townhouse has also been the subject of many research experiments. 

 

The Grow Home and The Next Home developed by Professor Avi Friedman from McGill University in the 1990s made the case for a standardized affordability through the demonstration of a type of row Core-houseadapting over time according to occupant needs. Each townhouse could suit the functional requirements of one to three households or even be divided to include a commercial or home office space on the ground floor. The Grow Home proposed a shell for owners to outfit as needed and as their potential to earn increased taking Habraken’s idea of supports and infill to the townhouse as a way of creating dynamic streetscapes from ordinary housing archetypes.

The American House-Carpenter «town house»