Prefabrication experiments - 452 - Vaulted concrete innovations

Modern materials and methods revolutionized building construction. Reinforced concrete specifically evolved though many varied experiments during the 19th century into a material associated with multi-unit residential typologies as the artificial stone is composed of widely available resources, it’s also solid, durable, affordable, and fireproof. These characteristics make it the most used man-made substance on earth. Its important advantages are somewhat offset by a high weight to span ratio. With an approximate mass of 2400 kg/m3, concrete slabs, beams, columns, and other components contribute to structure’s significant dead weight. 

 

Inspired by Gothic vault stone fan or rib spanning systems, Vaulted AG’s cambered concrete floors employ similar geometric lines of force to reduce material use and capitalize on concrete’s compressive strength. While this type of ribbing used in waffle slabs or onsite produced void slabs is a first step to weight reduction, vaulted slabs exploit curved geometries to further increase structural efficiencies. Vaulted AG makes it possible to assemble efficient floor systems from industrialized parts that are bolted together to facilitate their assembly and disassembly. The arched voussoir-like fragments support lightweight floating mechanical floor plates shaping an open void network for distribution ducts, piping and other systems.  The vault’s extrados surface is hidden within the floor composition, while the intrados creates a beautiful gothic-like ribbed arched ceiling. Vaulted AG is a spinoff from research undertaken at the Block Research Group of ETH Zurich by professors Dr. Philippe Block and Dr. Tom Van Mele. Their prototypes were first exposed at the Venice biennale in 2016. 

 

A typical prototype square floor grid is assembled using 4 irregular pentagonal fragments supported by corner columns. An 8-sided central square concrete compression component locks all elements into place akin to an arch's keystone. Each pentagon’s ribs radiate from a thick intersection at the column junction and angled toward the central keystone exploiting a symmetrical arrangement. Perimeter tension members resist horizontal loads. According to inventors, optimizing compressive forces makes it possible to employ 80% less steel and 70% less concrete in a floor composition 65% lighter than a conventional one. Responding to the basic structural idiom of maximum span with minimal materials Vaulted AG revives historic building strategies to further modernize concrete construction.  

Floor system prototype

 

 

Prefabrication experiments - 451 - Micro-units designed for adaptive reuse

 

Adapting vacant, underused, neglected commercial buildings to respond to the affordable housing crisis can potentially be to today’s procurement challenges what the mobile home and cheap prefabs were to interwar and postwar 20th century housing production. Intensifying use of deserted central neighborhoods also leads to less sprawl revaluing derelict spaces. Many have suggested that adapting existing buildings to new functions is complex and costly, even arguing that new construction is cheaper. Considering its complicated logistics redeploying existing infrastructure offers environmental benefits by reducing, reusing and recycling components and materials.

 

Implanting systems for private kitchens and baths can certainly be expensive and structurally complex as most commercial building floor plates were not designed to service multiple flat layouts. Imaginative co-living patterns provide opportunities for sharing services; appartements can offer autonomous private spaces with wet core services placed to be shared among many occupants, reducing mechanical distributions. This type of micro-unit community was projected by London firm SHED. The tiny units can easily be slipped into any building. The no frills living standards offer a safe and private place to live, sleep and work. They also help revive buildings that otherwise would slip further into disrepair. 

 

Tim Lowe, an architect from Studio Bark, the founder of the SHED project sees their approach as a win-win low rent strategy. Conceptually, the integrated furniture units are a type of Ikea kit framed within a streamlined supply chain; The modular volumes’ components can be produced serially to efficiently distribute low-cost micro-dwellings.  All elements including wall panels are designed to be assembled or even disassembled using a mallet and a screwdriver in a day. Insulated for acoustic and thermal comfort, interiors would include a small space for working along with a closed area for sleeping. All other dwelling requirements are shared.

 

In a typical central core office layout, the central core could be adapted to include common kitchen and baths using the existing vertical ducts with the living pods being distributed freely on the open floor plate. While admittedly not a total solution to solve housing shortages reusing existing infrastructure does substantially diminish massive material extraction required by new edifices.  

Moveable unit in an existing building

Prefabrication experiments - 2024-25 - Joyeuses Fêtes - Happy Holidays

 

Prefabrication experiments - 450 - Chemehuevi prefabricated housing tract by Pierre Koenig

Modern as well as neo-modern architecture theories and ambitious social reforms aimed to democratize quality design cultivating some of its most well-known canons. From Jean Prouvé's Citroën worker Shell Dwellings in the 1950s to Kieran and Timberlake’s Cellophane House in the early 2000s, modernist prototypes envisioned industrialization as a tool to reform housing production. Among these initiatives, California Arts and Architecture’s Case Study House Program sought to bring European modernism's tenets to the USA. The program outlined some of the most iconic examples of mid-century modern houses including the grandiose Case Study House 22 (The Stahl House) designed by USC graduate Pierre Koenig. Steel and glass framed a dynamic spatial composition that could be generalized to develop reproducible (in theory) dwellings based on these new materials and methods. Koenig advanced these experimental strategies in his own house, while still studying at USC in the early 1950s. Promoting modernist principles remained Koenig's obsession until the late 1970s. 

 

Convinced of good architecture's potential to serve, Koenig accepted a mandate though the University to work with the Chemehuevi native American tribe for a new tract. From 1970-1976 the project for a series of prefab houses was mired within a process more complex than he initially expected. Working within HUD’s parameters and discussions with the tribe demonstrated the inherent difficulties of providing affordable dwellings go well beyond architectural composition and require political will as well as design talent. 

 

The small 20x20-foot grid Koenig developed could be expanded to a 20x80-foot longhouse type. The prismatic steel structures included appendages for exterior living spaces, carports and used a basic grid to suggest an open variable construction system where kitchen and bath locations could be determined and varied individually. The proposal for the reservation developed upon a specifically modern esthetic using design elements the architect explored in far more luxurious houses. The small modern prototype positioned the potentials of new materials and methods against government prescriptive policies on housing which limited innovation. As Koenig himself observed and related, «in the end the houses were too nice, politicians didn't want the Chemehuevi to have better houses than they had themselves».

 

For more information see:

deWit, Wim. (2011), Modernism Thwarted: Pierre Koenig's Work for the Chemehuevi Indians. Getty Research Journal, no. 3, p 87-98

Chemehuevi prefabricated housing tract, on Lake Havasu, Calif., 1976

 

Prefabrication experiments - 449 - Mass Affordability - 10 - Quonset Huts...again

 

Affordability and prefabrication have been correlated in the production of mobile homes, postwar bungalows, and largescale panelized concrete buildings throughout Europe. Manufactured housing replicates housing processes and elements over many instances decreasing costs through harmonized supply chains, bulk orders, and standardization, all principles of mass production. Rationalization is articulated to minimizing specialized or individualized demands. Another strategy normalizes similar systems for varied uses. The same free-spanning structure determined for storage can be transformed by adding prefab stairs, bath or kitchen pods producing a ready-made flat, temporary or permanent. 

 

Reducing the number of composing elements and parts to build multifunctional inhabitable structures is based on structurally efficient shapes and geometries that are easy to assemble and disassemble. The A-frame, Butler frames, and barrel vault huts are examples of low-cost structures that combine walls and roofs into a simple space defining and covering approach to building. Architects and industrialists have seen ready-made kit dwellings in these unpretentious volumes to efficiently address housing shortages. 

 

A recent proposal in Detroit designed by EC3 architects showcased the SteelMaster manufacturing capabilities to revive the affordable dwelling possibilities of the Quonset Hut Prefabrication experiments 15. The semi-circular extruded vault gained popularity as an instant airplane hangar, storage unit or emergency hospital during the second World War. Just outside Detroit's downtown disrict, eight barrel vaults are aggregated into a community. The steel structures are domesticated by adding curtain walls to each gable end. Polycarbonate panels and personalized lighting accents add touch of contemporary design to the manufactured arched elevations.  

 

The eight units provide rental spaces for live-work spaces for artists or start-ups.   The restrained interiors are organized around a wood framed wetcore, which also includes a staircase and supports a loft sleeping area. The ribbed corrugated arches are insulated by interior curved plywood or timber framed enveloping ceilings that weatherproof and conceal the steel vaults on the inside while their extrados surface is a completely recognizable community figure.  The simple to produce and build elements highlight that reducing a house to its most basic elements, floor, curved enclosure and a service hearth contain some answers to the affordability dilemma.

Barrel vaults during construction

 

 

 

Prefabrication experiments - 448 - Mass Affordability - 09 - Refitting existing buildings with Kit Switch

 

The pressure on affordable housing supply is continuously increasing.  Accumulating shortages are overwhelming, construction costs are ballooning and productivity stagnating. These challenges affect the provision of everything from single family dwellings to collective urban blocks. Conventional construction and its supporting supply chains are inconsistent, new building construction requires long drawn-out permitting procedures and developing unbuilt sites is wasteful compounding environmental challenges. 

 

Densifying existing neighbourhoods and infrastructure can reduce pressures associated with delivering entirely new tracks. Retrofitting, reusing, and adapting existing buildings that are less than optimally occupied can be explored as levers to provide housing opportunities: Building over strip malls, adapting disused commercial buildings, repurposing high vacancy office towers can relieve pressure on new lot and infrastructure planning. 

 

Hacking existing open-plan buildings with simple structural systems or grids potentially also decreases pressure on permitting processes.  Most commercial floor plans based on a 7,6-meter grid could be redesigned into loft spaces as has been demonstrated time and again by transforming factory buildings in gentrifying industrial neighbourhoods.  However, the complexities of adaptive reuse are not specifically linked to architectural potentials or structural challenges (which can sometimes exist with new seismic or even fireproofing constraints) but to mechanical transformations. Office and open-floor plates were rarely designed for the required multiple service networks needed to juxtapose flats, most were planned with one centralized service core.

  

To address these opportunities and challenges, Kit Switch https://www.kitswitch.com , an industrialized service core producing start-up is developing flat-packed industrialized wall-packs for fitting kitchens and baths into existing buildings. Panelized with coordinated distribution of power, water and HVAC equipment, these service-cores streamline fit-outs by standardizing and modularizing typical dimensions, distributions and connecting them to vertical chase elements that are cut or drilled into existing floor plates. While these modifications can be time and resource intensive, they imply much less extraction and resource use when compared to new builds.  Costs as well as gains of retrofitting existing infrastructure should be weighed against the important carbon footprint of producing new concrete, steel, aluminum and all other materials that go into the erection of equivalent buildings.

Image from the Kit Switch website

Prefabrication experiments - 447 - Mass Affordability - 08 - Small Serial Houses

 

 

Modest serially made houses have demonstrated the potential application of industrialization to dwelling supply. Using mass-produced modular metal panels and a steel frame led to one of the most famous prefabricated kit house experiments of the twentieth century: The Lustron House promised to achieve in housing what the assembly line and folded plate metal had successfully brought to Ford co. A streamlined process of scaling supply chains to produce frames, panels and components in an easy to deliver and assemble kit would make quality houses economical.

 

Production of Lustron began in the United States in the late 1940s, but never attained the commercial success that had been championed by investors and government policy underwriting steel's mass application in civilian use in the shadow of the second World War. The underlying concepts of Lustron explored by its promoters had also been part of architectural fantasies and budding pedagogies. 

 

One proposal, envisioned by Marcel Breuer, The Small Metal House (Kleinmetal haus) designed in 1926 prefigured the building materials and coordinated systems used for Lustron but with a specifically modern aesthetic. The minimalist geometry and aesthetic epitomized Bauhaus training studied as formulas for bringing quality architecture to the masses. A starting point for a modular pattern book of houses with each dwelling design using the basic components to develop personalized plans according to user needs would, today, be considered as mass customization or even as an innovative platform theory applied to housing. 

 

Revolution 4 Architecture’s Modern Modular and a growing list of other contemporary architects argue for platform modularity to democratize good design at low cost; the architect’s vision is disseminated among many consumers. What is usually thought of as unaffordable (mandating an architect to design a custom home) becomes a marginal expense as architectural prowess, vision and genius is brought to the series or «models». Once the prototype is perfected, its principles are applied en masse. The small metal house provides a vision into the industrial serialization of architecture by componentizing and aggregating organizations into patterns. Like many modern architects it seems that Breuers’ mass customizable home was only a century ahead of its time. 

left: The Small Metal House ; center: Lustron ; right: Modern Modular 

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