Préfabrication experiments - 446 - Mass Affordability - 07 Low-tech Modular

 

 

Making housing affordable through industrialized construction ought to be a straightforward undertaking. Large numbers of repeating units scaled and patterned over easy to put together systems can be applied massively. Previous blog posts discussed mobile homes, lightweight timber framing or even large concrete panel systems in pre and post war Europe. All deployed a simple but effective recipe: Sharing building systems among numerous projects and across contexts requires less design resources and can further be democratized in a type of sharable housing kit outlined by basic parts tweaked to respond to functional and regional parameters.

 

British architect Walter Segal introduced DIY open frame structure to 20th century architectural practice Self-build and similar ideas can be traced to Japanese traditional post and beam structures repeating dimensions and principles to achieve an efficient and resilient housing supply.    Elemental Architects’ Incremental Housingreaffirms these simple principals of mass-producing parts adaptable enough to be arranged and even rearranged according to needs in an open-source design strategy. 

 

A recent proposal by Bernardo Horta for a co-housing community in Brazil, the Cumbe Housing Project, outlines a skeletal post and beam structure to shape modular living units that can be used as stand-alone micro dwellings or combined in a multidirectional framework to create multi-room or even multi-flat dwellings. The bolted columns and beams frame a double shed-roof portal frame section. Gable ends could be combined with other modular units to organize a linear row-housing strip. Precut timber parts are used for the structure, recycled tires filled with concrete are suggested for foundations and end walls are infilled with wattle and daub influenced by vernacular building traditions. Front and back elevations are left to be customized according to occupant needs and could feasible be infilled with low-tech local materials that do not need any intensive labor. Horta’s proposal intends that all other required elements, doors, windows and other building pieces be added and adapted according to local supply chains and even changed, replaced or reconfigured over time as owners’ economic conditions and product supply evolves.

Cumbe Housing system components

Prefabrication experiments - 445 - Mass Affordability - 06 - Typical Cell

 

Recognized for his contributions to the Russian avant-garde and Suprematist Movement in the early 20th century, El Lissitzky, a polyvalent designer/artist, embodied a total work approach to developing his ideas.  The designer as an actor for social change capable of improving living conditions was at the heart of his artistic and design positions. While his list of built architectural works is short, consisting of only one building (a printing plant), he left a long trail of prospective explorations and their representations. One of his experimental paper projects, at the intersection of housing, architecture, industrial and furniture design, the F-type Residential Cell (1927) projected a reproducible dwelling unit studied to harmonize all dwelling functions in a comprehensively integrated design. 

 

Built-in furniture composed the flat’s architectural arrangement around a split-level section accessible from a lower floor.  The potentially mass-manufactured unit was articulated around a two-flight stairwell dividing day and night spaces. The two-level organization shifted from the ordinary one floor flat showcasing that stacked units in a housing block could include multiple levels with the spatial qualities found in single-family dwellings. The modular multifunctional built-in services would facilitate production and lower construction costs as all cabinetries would be made from the same basic components and catalogued design options. The cell's amenities previewed a future for the house or dwelling as an ergonomic machine capable of responding to modern needs. Storage walls, transformable cabinets, movable partitions, all presented a flexibility and changeability adaptable to varying living patterns. 

 

Foreshadowing modern kitchen design, the F-type was equipped with modular cabinets that could be combined, based on the same dimensionally coordinated cases, to arrange multiple organizations. Looking at housing from the perspective of a cabinet or furniture design scales and applies the production and productive attitudes of component modularity to architecture; Built-ins not as onsite built elements but embedded in typical flats. Borrowing and adopting synergies from industrial design to achieve truly holistic architectural works, that could be repeated en masse to achieve what industrialization has rendered in every other industry apart from architecture: productivity, greater quality and reduced costs. 

Typical cell model photos

Prefabrication experiments - 444 - Mass Affordability - 05 - Rational flexibility

Providing accessible and affordable dwellings requires the rationalization of expenditures through a coherent spatial, structural and functional organization along with efficient material use optimizing each square centimeter of built form. This parsimonious vision outlines the fundamental aspects of the “core-house” as a tool for expandable growth based on user needs and agency. Controlling costs through service core principles has been applied to single-family dwellings with some success (https://prefabricate.blogspot.com/2018/12/prefabrication-experiments-182.html). These same ideas have also been applied to office towers or multi-unit residential edifices to offer opportunities to moderate construction costs while offering systemic adaptable planning.

 

Typified by a 10 storey multi-unit prototype built in France in the early 1970s by the modernist architect sibling team of Luc and Xavier Arsène-Henry, the Montereau residential core-tower borrows from 20th century office building organizations and blends it with adaptable housing design. The pinwheel plan is configured around a vertical circulation core. From the centre point, long spanning concrete slabs structure 4 radiating unit-spaces per floor arranged on a 900 mm grid. Each rectangular flat 13.5m x 6 m is then articulated to the floor plan by a mechanical vertical conduit used for plumbing and electrical service distribution. 

 

Around these service hubs, each unit can be composed to relate to two different orientations with multiple configurations. Further, core-adjacent spaces can be fitted-out by occupants using the predetermined 0.9x 0.8 m channel as an evolving planning device. An exterior balcony bounds the floor plate providing exterior spaces for each apartment. All rooms and living spaces’ dimensions are a multiple of the 900 mm grid and were divided by prefabricated stressed skin panels held in place by removable compression screws making spatial arrangements flexible, malleable and adaptable. Architects envisioned typical floor plans for each occupant to adopt or modify according to their own living patterns. 

 

Not designed specifically with low cost in mind, the frugal planning was geared toward changeability. However, the same principles that make the space flexible, free and open floor plates, unfinished spaces, repeating mechanical cores, a rigorous structural grid, standardized interior systems along with predetermined parameters to control change can also help reduce construction costs. 

Montereau flexible planning scheme

Prefabrication experiments - 443 - Mass Affordability - 04 - Robotic Masonry

 

Expressed by harvesting and arranging local, low-tech materials, masonry construction's character has always conveyed a type of humbleness and affordability linked to its relative simplicity. Building any compressive structural form with dimensionally stable elements geometrically dry-locked or bound with mortar, reinforced or unreinforced, has provided both versatile and long-lasting buildings. Artisan-based masonry construction has also been highly industrialized: Blocks, bricks and binding agents manufactured with rigorous precision, constituent stability and modularity can be stacked for bearing or cladding wythes. Recent labour shortages, specifically in traditional trades, have had many looking at novel ways of introducing digital technology to the age-old process of bricklaying to refresh its pertinence and conserve its historic frugalness. 

Digital fabrication, using robots, is being examined for making complex shaped bricks or blocks to create structurally informed geometries, to stack bricks in intricate patterns that would be difficult for even the most skilled mason, or simply to make quick work of a running bond. Emerging Objects, Gramazio and Kohler or even ShoP Architect's parametric masonry work at Mulberry House in New York present a new set of opportunities and parameters for masonry-based assemblies. Can the link between new technological potentials and affordability be found in replacing an ageing workforce with flexible site-based automation and digital mechanization ? 

Related to how large scale 3d printing is presented to produce affordable dwellings with on-site mechanization, SAM (semi-autonomous mason) and Hadrian X (fastbrick system), are similar versions of numerically controlled robotic arms. Both precisely place units to shape architectural form. SAM, conventionally completes the process of installing cladding by delivering, buttering, and setting bricks at a rate of 3000 bricks per day (500 is the average rate for a mason). Hadrian X proposes a comprehensive house building process. The Fastbrick Wall System is a combination of blocks, adhesive and an exterior acrylic stucco to produce a finished wall. The system could conceivably be delivered to any site. Further the aligned cores within the proprietary blocks are used to reinforce the system with steel rebar and easily distribute wiring and plumbing to produce a comprehensive building system.

top left: Emerging Objects; top center: Gramazio Kohler; top right: SHoP Architects
bottom left: SAM; bottom right: Hadrian X

Prefabrication experiments - 442 - Mass Affordability - 03 - “Unfinished”

 

Providing adequate affordable housing in the context of labor shortages, massive population displacements, and increasing construction costs requires inventive propositions to address an unsolvable problem. Building repetitive pattern houses and designing smaller units have proven to be a way forward in eras and contexts requiring urgent supply. Offsite construction and prefabrication were deployed during similar times of crisis to respond to exploding demand; Even while prefab systems proved an effective way of increasing output, the bare bones construction materials and methods linked to their affordability proved to be their downfall as prefabs became associated with shoddy construction.

 

Another idea linked to reducing costs has appeared from time to time with equally connoted results: providing adaptable systems that can be customized and even finished by their occupants. Unfinished, The DIY house, The Naked House, The Grow Home and even The Half House designed by Pritzker winner Alejandro Aravena identify home finishing as an important part of initial costs. Most of these proposals argued for a mechanical core, structural system, and climatic shell to provide basic and initial dwelling spaces. Elements left for personalized fit out would be completed by owners and as they became economically feasible or required. Some have gone so far as servicing unfinished bathroom and kitchen spaces with plumbing and electrical distribution capped at fixture fittings.

 

The upfront costs of these unfinished houses can be 40-50% less than a comparable finished product. While this can be an economic advantage and even help reduce borrowing budgets, it’s not clear how the long-term finishing will impact overall costs, or if finishing one’s own home is applicable in all contexts, or culturally tainted. Still strategies like The Naked House presented at the Venice Biennale in 2016 as part of a British team of designers proposes generic spaces that can be functionally determined and altered during the home’s lifespan. Reducing upfront material use certainly provides an interesting way of lowering construction costs, however piecework fit outs done one at time, can increase total costs of building providing a framework for higher profit margins and reduced responsibility for builders; a naked house is certainly less expensive than a completed house however it is also just that: unfinished. 

Above left: Wikihouse (DIY); Above right: Half house (Aravena); Below center: Naked House

 

Prefabrication experiments - 441 - Mass Affordability - 02 - State Organized Construction

 

Industrialization and the subsequent marketplace commodification proved that the invisible hand (Adam Smith’s vision of the free market) commanded mass production, by replicating standards, tasks and procedures to reduce costs and normalize quality. A centralized strategy that supports and harmonizes supply chains with design, manufacturing and commercialization is the basis of any successful production strategy.  Similar ideas have been envisioned to provide affordable housing through highly integrated industrial procedures.    Government run factories for precast concrete panels, volumetric modular units and components highlighted postwar production in the USSR as the socialist republics perfected building systems. The panel block was the most iconic result inspired by and patterned over Ernst May's experiments in Germany in the early 20thcentury. May’s ideas were expanded by the USSR’s construction policies. Planning, designing, manufacturing and onsite assembly were all synchronized by a centralized procurement and provision strategy based on typical buildings shaped by a modular grid: a major dimension of 3m with a minor dimension of 30cm, controlled by a rigorously applied 10cm coordination matrix.    This productive model motivated many other countries; An American delegation traveled to the USSR in 1969 to gain a better understanding of the government run factories and study how off-site construction was generating the kind of housing output that the US required. Many of Operation Breakthrough's systems were derived from panelized or precast mega block construction.    Program underwriters’ justification for high levels of industrialization foreshadowed arguments made today: 40-50% less labor, 35-45% faster, higher quality and year-round construction. The Gosstroys, state construction committees, at the republic, local and city levels oversaw all Soviet construction from providing sites, financing, typical building designs, to harnessing new materials, machines and methods. Academic and research institutes governed by the centralized Gosstroys framed research grants according to specific innovation potentials. This concentrated method of decision making certainly made it possible to construct vast amounts of housing, however it also formed some of the negative connotations still haunting construction's industrialization.    Perhaps the lesson for today's housing crisis is the need for government involvement to stimulate and standardize processes while encouraging open design frameworks to avoid the total repetition of patterns that gave us the brutal panel block. Nine storey panel block from 1967 catalogue of typical buildings

Prefabrication experiments - 440 - Mass Affordability - 01 - The Balloon Frame

Urbanization, population migrations, political instability and economic crises engender globalized pressures that make suitable and sustainable housing provision one of the most imperative challenges of the 21st century. The generative potential of manufacturing applied to housing supply provides a renewed topic for reforming longstanding productivity issues in conventional construction. The ten next posts will look at some of industrialization's successful strategies for responding to vast housing crises of past eras.

 

The expansion of populations on a new continent in the early and mid 1800’s outlined requirements for everything from houses to barns, to places of worship and everything in between. The mass adoption of light timber framing, specifically the balloon frame, in the midwestern part of the USA soon branched out to every part of America. As opposed to heavy post and beam construction with complex joinery to ensure stability and durability, the cruder framing required only milled timber and cut nails to create buildings of any type and shape. 

 

Sometimes attributed to George W. Snow, a Chicago carpenter, the light timber frame was not invented but evolved through shared knowledge and the collective simplification of traditional half-timber construction. The system characterized by two-story vertical studs democratized through simple techniques, nailed assembly, is strengthened and stabilized through structural redundancy. Vertical, horizontal and diagonal bracing members placed close together in a filigree box frame streamline supply chains from forestry to mill to suppliers, builders and consumers. The system’s no-frills D-I-Y quality became an integral part of Americana, used to build pattern buildings, cottages, cabins, A-frames, and provided the basis for the most successful application of low-cost manufactured housing principles: the mobile home. 

 

Today’s version of the balloon frame, known now as the platform frame is still one of the most economical and generalized building structural archetypes. Included in panelized structures or modular volumetric structures, the mass production of cheap, standardized, well recognized and available building components is a central principle of lowering costs. The design flexibility from the same simple parts also displayed light-framing as a model the world over for low-cost and low-tech building.

left: Balloon Frame; right: mobile home framing

Prefabrication experiments - 439 - Catalogues and styles

 

A spinoff of the spawning 20^th century automobile industry, early mobile home manufacturing deployed mass production principles to build affordable dwellings. These principles are well documented; building a lightweight timber structure over a steel platform, wheeled out of the factory, delivered and installed on any site. The pre-cut kit house also used mass produced timber frames but from a different value proposition in as much as its design process offered increased options; pieces could be shaped and packaged for multiple configurations less affected by transport criteria. 

 

Both models of twentieth century prefabrication used plan books to organize procurement. Clients could choose from designs articulated to harmonized modular strategies and supply chains. The Sears catalogue of houses is probably the most famous and inspired other companies like Canadian icon Eaton to offer their own version. The number of designs was staggering when analyzed in relation to what architects often decry as standardized prefab. 

 

The conceptual distance between how industry and architects interpret the catalogue endures as an interesting dilemma for manufacturers. While architects have often argued against style to inform patterns and pastiche architectural compositions, their proposals remain relatively similar in terms of fundamentals differing only in aesthetic orientations. Resolution 4 architecture's took on the modular catalogue «The Modern Modular» with what at first glance seems like a third option: A library of spatial components and modular variability anchored to an objective of spatial and production rationalization. However, the aesthetic remains manifestly modern defined by clean and minimal lines. 

 

Is architectural variability truly about singularity or is it about style. The Eaton catalogue contained traditional designs outlined by similar detailing and volumes, while Res4’s architectural approach more closely mimics a type of pattern language leading to houses that all look the same, hardly singular. Industry’s take on the precut house was in a sense at once rational and varied. Contemporary architects argue that prefab should be organized around similar components, nonetheless, mostly tainted by modernist attitudes. This aesthetic and disciplinary-informed gap between architectural sophistication and generally palatable designs continues to hinder prefab’s streamlined application.

left: Eaton Catalogue; right: Resolution 4 Architecture modularity

Prefabrication experiments - 438 - Concrete Tube Utopias

 

The previous blog posts have discussed housing types from micro-dwellings to industrialized utopias and large-scale urban renewal proposals. Each motivated to efficiently supply quality dwellings for the masses affordably and with sufficient flexibility to respond to varying dispositions. Current generalized urbanization challenges existing models toward the production of dwellings while simultaneously reducing our collective environmental footprint.  Conventional housing construction is a slow go, fraught with planning delays, bogged permitting and symbolized by lagging productivity. 

 

Repurposing ready-made industrialized objects for housing urgencies is a recurring theme and has spawned an assortment of schemes including converted shipping containers or stacked mobile homes. While designed in different eras, two proposals demonstrate the cyclical nature of architects inspired by redirecting manufactured products for other uses. Guy Dessauges (Living Tubes, 1966; blog article 28) and James Law architecture have both represented concrete infrastructure pipe sections as modular building blocks for quickly putting flats together. Dessauge’s tubes were envisioned around a centralized service core or stacked three stories high composing a housing hive. The Opod Tube House (2017) proposal visualized in multiple contexts clearly borrows, consciously or subconsciously, from the same Zeitgeist.  

 

Can lessons be learned from these radical investigations for creating affordable housing or are they just exercises architects have come to adopt as their discipline’s way of addressing crises? The amount of rework needed to adapt products to housing is often absent from designs and sometimes asserts disciplinary caprice. The discipline’s «modern» heritage of rewiring industrial designs to imagine novel building systems reforming classic ways of building is entrenched in this type of poetic license that has often led to socially, economically and culturally untenable proposals. 

 

Most architects are far removed from economics, manufacturing and streamlined production that the only way they feel that they can contribute to solutions is by resorting to romantic views of prefabrication as the simple assembly of premade forms. The truth is that adapting ready-mades can be complex: mechanical systems, interior infill, site infrastructure and other retrofit requirements makes this type of stacking less than credible and financially unfeasible.

above: Opod; below: Living Tubes

Prefabrication experiments - 437 - XL(towers) - Vertical neighborhoods

 

Relating the advantages of the single-family dwelling (privacy, spatial distribution on multiple floors, four orientations for views and exterior spaces) with the benefits of collective housing (density, shared services, proximity) has inspired architects since industrialization created an magnifying need for affordable urban housing prototypes. The last few blog posts have referenced Le Corbusier's Unité d'habitation based on amassing rationalized two-floor flats, Metabolists’ plugins aggregated over shared towers along with an idealized view of a multi-floor infrastructure to accommodate homes represented in Site Architect’s Highrise of Homes (1981).

 

The flagship endeavor for this productive vision of high-rise suburban living is Habitat 67 constructed for the Man and his World exhibit in Montréal, Canada (1967). The modular prestressed and post-tensioned concrete mega-blocks were cast and amassed to create an architectural statement about the potential future of housing that never manifested. Still this architectural dream endures in its most at once naive and foreword looking manifestoes. 

 

Chicago studio Kwong Von Glinow  projected a tower of multi-story houses for Hong Kong. The design won first prize for the Hong Kong Pixel Homes competition in 2018. The modular boxes would be stacked up to four high to organize single houses and apartments vertically instead of the horizontal relationships conveyed in conventional planning. Juxtaposed single, couple and family units are intended as a type of vertical unit – a neighborhood - activating dynamic collective spaces between units. The interiors could be fit-out according to inhabitants’ needs and eventually evolve over time. While the theoretical proposal is rendered to showcase a mass to void relationship that allows for vertical patios, views and rich interior/exterior relationships, the real-life viability remains to be proven. Designed in groups of four stories, the proposal echoes the need for a type of primary support structure to carry each stacked neighborhood, which would allow for streamlined replication of modular units. As developed in a timber tall building in Norway, Treet, the four-story stack built on a infrastructure floor is a credible option for realizing this contemporary take on the vertical distribution of individualized dwellings.

left: Pixel competition design ; right: Treet section showing two «support» floors

Prefabrication experiments - 436 - XL(towers) - Stacked dwellings

 

Skewering identical floor plates on a vertical axis is the most common way of building dwelling towers. The inhabitable hives are optimized by aggregating units effectively around centralized service cores. Composing tall buildings with variable floorplates, while certainly less commonplace, has inspired many architectural proposals based on adaptable floors conceived as free indeterminate spaces tuned to present needs as well as being adjustable to change over time.

 

The tension between pragmatic building strategies and individualizable housing needs arguably also led to the invention of both the megastructure tower and the development of open building theory. SITE architects' evocative representation Highrise of Homes (1981) or Elmer Frey’s stacked mobile homes, both represent the underlying duality of any collective housing scheme of according common and private functions. The floor plate designed as infrastructure for any organizational scheme harmonizes these parameters and inspired examples of the support versus infill patterns related to Habraken's visions for mass housing.

 

Isay Weinfeld, IW Arquitetura's 360° tall building in São Paulo, Brazil is a contemporary vision of particularizing tower geometry with varying and open slabs. Each storey is composed of large spanning reinforced concrete, onsite cast, waffle slabs cantilevered from a rigorous grid of columns and central service core. Each floor is infilled with modularly organized flats shifted from one floor to the next in a pinwheel composition to enhance the tower’s dynamic form. Further, the 62 units are massed to create voids identified by their designers as yards revealing a vertical urban plan imagery for the tower. 

 

The stacking of identical units into an accommodating slab frame makes it possible to manufacture systems as completely replicable chunks without the habitual reinforcing required for lower modular units or elements to support their vertical neighbouring units. The 360° tower demonstrates the enduring architectural attraction for customizing interiors in a structure as a service rack of endless possibilities. This approach, while distant from Japanese Metabolists’ complete plug and play theories reveals how Sites' representation of an ideal customizable vertical city is still a forceful fantasy in architectural culture. 

top left: Highrise of Homes; top right: stacked mobile homes; bottom: 360° Tower

Prefabrication experiments - 435 - XL(towers) - Taller is better

 

Occupant protection is a fundamental purpose of housing. Defensive posture is usually defined by how a home is anchored to its locus. Dugout or elevated, position relative to ground plane symbolizes how humans delineate their territory and how they interact with other humans; The need to observe surroundings, showcase one's wealth or power, and dominate the environment stimulated the development of the tower house type. Cities in the middle-ages were stages of power struggles represented by the multiplication of elevated dwellings as devices for celebrating a family's wealth - taller was always better.

 

Verticality as an expression of wealth and power took on a manifestly modern connotation as new materials and construction methods made it possible to reach greater heights and spans unlocking a potential for spaces, commercial or residential, to be stacked democratizing what had been theretofore limited to the ultra-wealthy. Mechanization, steel, reinforced concrete and light curtain walls unleashed new industrial energies. The tower became a symbol of urbanity powering new cities into the twentieth century no longer related to one family. Granted, many private promoters and construction magnates were still sometimes controlled by a family who continued to prove their influence by harnessing resources and deploying them into magnificently tall buildings. 

 

The tower as a multi-unit dwelling typology is straightforward: flats are distributed, aggregated and piled around a central core containing mechanical distribution and circulation. Flat typologies, anchored to a core, can be one, two and sometimes three stories high with single, dual, triple or quadruple orientations depending on the core-to-flat configuration. The typical floor plate repeating the systemic relationship from floor to floor makes these edifices conducive to rationalized construction methods. 

 

Modular volumetric construction has been proposed, marginally applied and offers a glimpse into the strategy's potentials and limitations. While certainly formidable in terms of speed of construction, in conventional systems, lower boxes carry the weight of upper boxes. Tall prefab and modular construction using repetitive units imply the use of an expressed or hidden support structure or the particularized reinforcement of each manufactured box, which makes the seemingly simple stacking challenging in terms of mass production and can also increase construction costs. 

above: Bologna tower houses; below: Capsule tower by Kisho Kurokawa

Prefabrication experiments - 434 - XL(slabs) - Umbrellahaus TM

Modular volumetric construction is characterized by three-dimensional, factory produced boxes. This approach sometimes associated with slab buildings, is generally based on repetitive structural grids conducive to typical floor plates; flats with similar dimensions and attributes are simply stacked and coupled. The slab typology doesn’t expressly direct to volumetric as the sole solution for putting these buildings together, however, coordinated, transportable boxes can certainly streamline certain parts of a construction timeline. Further, modularity can be leveraged toward scaling container-like flat types among many housing projects using the same basic structural elements and systemic components - a strategy now identified as a platform approach to building. 

 

Designed and trademarked by Chapman Taylor www.chapmantaylor.com   Umbrellahaus deploys the current interest in offsite along with modular volumetric reasoning in the UK to demonstrate a building «platform» to tackle current housing shortages. Suites are outlined by industrial parameters, notably, manufacturability, transport maximum dimensions, assembly and setting details. All apartment unit sizes follow the London Plan space standards.  These design and production considerations are matched up with a variety of lifestyle compositions to propose an array of dwelling configurations from studios to family apartments within the overall framework of a slab building.

 

The concept encompasses more than just modular volumetric construction as it proposes to connect new buildings to their contexts proposing a multifunctional urban infrastructure to avoid the segregation and difficult living conditions connoted by mono-use post-war prefab block neighborhoods. Once the units are stacked in place, several cladding or material solutions can be applied to suit site conditions, architectural tastes and building arrangements. Standardizing design criteria along with a streamlined regulatory approval and a liability framework, the Umbrellahaus platform covers every aspect of the project procurement process.

 

The proposal also addresses long-term adaptability; inhabitants could change from one unit size to another as their circumstances change, without leaving the building. While this certainly can help overlay the units’ design options in tune with lifestyle evolutions - it remains unclear how this theory would be put in place in a densely populated building.

Modular volumetric Umbrellahaus

 

Prefabrication experiments - 433 - XL(slabs) - Streets in the Sky

 

Known for their important contribution to Team 10, an architectural collective formed from the Congrès Intérnationaux de l'architecture moderne's (CIAM) dissolution, Alison and Peter Smithson’s theories and projects were a fundamental part of nascent postwar brutalist visions and pedagogy in the UK and abroad. Mat-building previously discussed in blog article 282 envisioned urban form that rejected buildings as singular objects, exploring instead a symbiotic spatial relationship between urban geometry and building topologies. 

 

The couple married in 1949 and founded their own firm in 1950.  Their radical visions for integrating public spaces in collective housing led to imagining access walkways as «streets in the sky» redefining the slab type. The iconic Robin Hood Gardens, a social housing complex in East London, demonstrated the use of exterior access corridors at different levels large enough to support both personal and social spaces. Their design deconstructed the classic slab by placing these common voids within the structure's volume. A proposal, Terrace Housing City, took this one step further by arranging an oblique slab cross-section as a series of vertical volumetric setbacks from floor to floor flooding each floor plate's exterior skywalks with sunlight. The Streets in the sky imagery influenced many social housing proposals aiming to attribute streetscapes' spatial richness refuting the boring interior corridors synonymous with the slab. 

 

The construction of floating social spaces including roof terraces had already been proposed by modern architects, proficiently by Le Corbusier. Aerial passageways leading to flats became a symbolic component of these modernist visions and were applied most notably at Habitat 67 designed by Moshe Safdie.  Contemporary architects also reframed and refreshed the same objective of social interaction in a dense block: French architect, Jean Nouvel, designed a ship like cross-section at Nemausus in Nîmes, France, with large promenade decks. Multiple meters wide, the catwalks leading to access and exit stairwells were planned as a way of rationalizing costs by externalizing costly elements usually built within the slab. Their removal allowed for them to be built with lighter construction systems and materials redirecting these potential economies to offer larger housing units.

Sections though aerial walkways

Prefabrication experiments - 432 - XL(slabs) - ZUP at Bayonne

 

Interwar years in France intensified dwelling as well as urban hygiene crises. An estimated 5 million units lacked running water and basic services. The devastating damage to hundreds of thousands of buildings during the second world war exacerbated this need for quality housing. In response, centralized policy sanctioned new dense developments all over the country under the label, ZUP - Zones à urbaniser à prioriser (liberally translated to Priority Zones to Urbanize). Projects and their promoters which provided a minimum of 500 units in tightly packed edifices required affordable and efficient construction methods to be deployed at scale. 

 

The slab block was adopted by an industry increasingly articulated to reinforced concrete; a material the country's inventors (Hennebique, Monier, Lambot and many others) had been central in cultivating. Beyond the material's advantages in terms of fireproofing and strength, it also lent itself to all types of prefabrication strategies. Marcel Breuers' flagship ZUP design for 1100 units at Sainte-Croix/Saint-Esprit, in the small community of Bayonnne explored precast concrete construction to propose a formidable building system. Designed and built from 1963 -1967, the master plan included dwellings and several services including a school and shopping center.  

 

Using a factory cast wall panel system inspired by the Camus System (also invented in France), Bayonne buildings were arranged as a cellular hive of flats and simply covered in a precast thick panel. The basic structural strategy of walls and slabs at Bayonne was cast on site using a tunnel form system:  a moveable prismatic formwork that defines a cell with a horizontal plane supported by two vertical planes. The tunnel forms are usually made of steel. Once the concrete is cast, the steel framed-moulds slide out and are reused on subsequent floor plates. 

 

The heavy wall panels’ architectural treatment at Bayonne showcase Breurer's talent and understanding of prefabrication's potential to create dynamic façades using mass manufactured components. The panels were cast as a thick solar shading device with built-in furniture and window openings. A mirrored pattern was repeated every two stories creating a textile like façade; the project's simple renderings illustrate how architectural regularity defined a coherent material field. 

Rendering of the Bayonne master plan

Prefabrication experiments - 431 - XL(slabs) - A failed prototype ?

 

Generated from industrialization and its new construction materials, specifically, reinforced concrete, the slab building was forged by assembly line production and its accompanying design theories. Thin, linear, rigorous grid organizations simplified structural design and service distribution, making these replicable arrangements ideal candidates for scaled serial production. The linear apartment blocks repeat floor plans and extrude sweeping vertical sections that sometimes seem to go on infinitely. This regularity is what made the slab a formidable affordable housing strategy but what also ultimately embodied the downfall of this expressly modern type.

 

Inaugurated in 1954 in St. Louis, Missouri, Pruitt-Igoe's 33 high density buildings underwritten by federal policy heralded the post war enthusiasm and urban planning doctrines associated with the slab block. The experiment like so many other modernist developments was rife with economic and social challenges.  Its symbolic demolition only years after its construction refuted modernist ideologies of mass housing.

 

Still, the slab endures as an iconic composition of flats designed to optimize collective and social cohesiveness. These buildings offer a rational way of using the same principles that gave us terraced housing but scaling them to taller structures. Recent proposals deploy the same underlying ideas to produce buildings from a generic aggregation of flats contextualized in mixed-use settings to counterbalance flawed modernist functional segregation. 

 

A contemporary example of a contextualized slab designed by Arrhov Frick Arkitektkontor in Sweden, is composed of a dual-oriented adaptable loft inspired units.  The typical floor plate of the Hmmarby Gård project is a multiplied sequence of two flats articulated to a shared vertical circulation core and arranged around a service hub surrounded by flexible living spaces.  13,6 meters wide, flats include large balconies on their north eastern façade and operable curtain wall façades on the opposite connecting the see through building to its surroundings. The repetitive plan makes a case for modern industrialized principles, repetition, modularity, standardization. This reproducible sameness that was decried more than half a century ago is valued as fashionable and mass customizable, elevating the slab from a once promising but failed prototype into a dynamic way of breathing new life into a city.  

Hmmarby Gård typical floor plan

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.