Prefabrication experiments - 481 - Off and On Site Challenges

The opposition between one-off building processes - bringing together disparate actors as a fragmented team for a singular project, and the harmonization of stakeholders under one roof for the scaled production of building subassemblies off site - endures. Beyond the successes of the mobile home, factory-made buildings have failed to achieve any generalized use even though the assembly line was touted as a disruptive force capable of reforming conventional construction modes. The current design and construction culture is one of the biggest obstacles to off-site.

 

The potential advantages of industrialized construction are multiple and well documented: preassembly in a controlled manufacturing environment, precise design for fabrication, bulk material procurement, iterative optimizations, waste reduction, standardized repeating details from project to project, rigorous quality control methods and efficient task overlapping - producing elements in a factory while other work proceeds on site compresses schedules, reducing costs linked to project duration and site management (winter conditions, equipment rentals, etc.).

 

While these important factors argue for greater use of offsite construction methodologies, beyond the negative connotations, industrialization implies some particularities and drawbacks that must be managed. Greater upfront planning, collaboration and required stakeholder engagement from design phases are needed to reform the highly discordant processes ingrained in conventional onsite construction. The necessary collaborative process can be facilitated by contemporary virtual design and construction tools to achieve the information and detailing required to plan for streamlined manufacturing, delivery of components and onsite assembly. Reduced onsite flexibility is also discussed as an obstacle, however it should be noted that the onsite bricolage may be flexible, but, it is also intensely wasteful. 

 

Architectural customization, singularity and cultural expressivity are also often cited as being unachievable with prefabricated systems. Buildings are anchored in settings that require civil, earthworks and groundwork adjustments that are not only difficult to repeat, but that characterize an edifice’s link to place. The interface between these informalities and the rigorous systemic repetition required for successful industrialized systems like modular volumetric construction should lead to new innovative systems and exploration aimed at marrying the cultural richness of individual sites with the efficiencies of offsite manufacturing. 

Setting Offsite produced house on site

Prefabrication experiments - 480 - Construction industry’s capacity to self-regulate

Conventional construction backers have generally shown resistance to embracing offsite construction. Further, the sector’s capacity to control what is and what is not adopted is an interesting case study in its autoregulation. The successful application of industrialization principles to produce buildings requires a special set of circumstances that balance supply, demand with simple building systems. Mass-deployed light-timber platform framing for single family dwellings, precast reinforced concrete panel blocks for collective housing in postwar Europe and box construction for mobile homes have all displayed the required perfect storm to harmonize supply and demand. Previous housing crises have provided these systems with the required equilibrium and impetus for adopting offsite construction systems at scale.

 

Current interest and vigorous policy are driving a renewed willingness to shake up the industry toward comprehensive manufacturing methodologies. This optimism is fueled by increasing demand for urbanized and affordable dwellings. However, market integration remains marginal. On-the-ground production capacity to respond to present needs continues to stagnate. The construction industry with its peculiar way of getting things done and archaic methods is self-regulated by this equilibrium of influences. A cultural transformation, even with massive investments and education to reorganize logistics would take years to induce wide-spread change.

 

Wide-ranging industrialization like the complete fabrication of buildings is not likely to take shape, at least not soon, and will remain marginal for several reasons, including the lack of stable demand and centralized purchasing agents. However, the autoregulating nature of the construction industry has already demonstrated the types of offsite construction that will further integrate the industry; panelized systems for walls, roofs, and floors, while less factory intensive than modular volumetric, bring a type of customizable prefab to the building site with the added value of partial systemic integration without the logistical challenges of more comprehensive systems. Panelized timber has already been massively adopted to reduce pressures on framers. Alleviating labour shortages with simple preassembly is showcasing how prefab can be part of the industry's capacity to self-regulate.

Timber framing offsite is now an integral part of onsite construction

 

Prefabrication experiments - 479 - Circularity and offsite construction

 

Designing for material circularity to avoid the «take-make-waste» approach common since mass industrialization implies a far more interconnected conceptual strategy including end-of-life considerations from the onset of both the design and construction planning processes. Buildings erected conventionally and according to modern standards are in a sense a heap of raw materials put together with all manner of durable connections, glues, weatherproofing membranes, plastics and wet joint compounds to perform in line with fireproofing, weatherproofing or other technical criteria and to maintain these conditions over a building's lifespan - durability has always denoted long-lasting. 

 

End of life scenarios in relation to materials and systems have rarely been considered and resources often end up in landfills as renovations are required, repeating the same wasteful processes.  Adaptive reuse, functional renovations, and energy retrofits are all ways of giving the integrated energy flows required to erect a building a second or even a third lifecycle moving away from linear processes. Keeping materials in buildings retains the carbon initially spent in service, while reducing the amount of extraction and production energies required for new construction. 

 

Offsite construction and prefabrication are often identified as facilitating circularity. Components are designed, produced and delivered to streamline onsite assembly and potentially their disassembly. This is theoretically possible, however, conventional building with all its regulatorily imposed seamlessness along with modern building culture's fascination with a minimalist aesthetic impede systemic disassembly: Removing plasterboard or ceramic tile, or continuous foam insulation, just to name these, implies destructive demolition making recycling and reusing of embedded components difficult - nearly impossible. 

 

A revolution in design is necessary. Design for disassembly, too marginally applied, should be integrated into construction standards, codes and regulatory frameworks to engrain buildings with a capacity for change. Offsite manufacturing in this respect can be conducive to circularity as assembly details are already designed to facilitate onsite connections and coordination. Managing resources throughout their lifecycle and planning for their reuse can also be facilitated through the data management required in manufacturing.

Façade components in the circular economy - TU Delft - by Christina Michael (2016) Master's Thesis

 

Prefabrication experiments - 478 - From Citroën to Citrohan

 

Inspired by principles ingrained in a mass production business model fostered by Henry Ford in the early 20th century, motorized vehicle production was centralized around single corporations. Automobile producers set their sights on domestic internal markets before endeavoring to expand internationally and long before partnering with the competition to share knowledge and platforms became the norm. Ford, FIAT, Mercedez-Benz, Skoda, and Peugeot all began producing cars nationally and inspired a revolution in the marketing of consumer goods. 

 

Car production was equally fundamental in pushing toward revolutionary changes in building construction and in architectural design. Seriality, flow production, piece or modular standardization, and mass-produced components all became underlying principles of modern architecture. Citroën in France began producing automobiles in 1919 in the same era that Le Corbusier was quickly becoming an iconic figure arguing for new mechanization methods to facilitate the serial fabrication of quality housing. 

 

His prototype for the Citrohan house employed his Five Points of a New Architecture as the basis of democratizing innovatively designed and produced dwellings. These three-floor prismatic units included a double-height living space that would become synonymous with some of the architect's famous proposals and was inspired by the architect’s fascination with painters' studios.

 

The whitewashed exteriors covered a traditional masonry unit construction system supported by the flat slab DOMINOpresented as an open construction platform. Based on François Hennebique's patents, reinforced concrete made it possible to build fireproof structures with open plans and non-bearing façades by replacing them with slender columns and thin slabs spanning 5-6 meters. 

 

Initiating a flexible approach to architectural planning, DOMINO could be infilled with any layout in plan and with large expanses of glass in elevation, replacing common openings. Le Corbusier's vision of brand equity with Citroën sustained and propelled the theoretical relationship between car manufacturing and building production. While this comparison is still evoked to showcase prefab’s potential, Citrohan succeeded in integrating architectural folklore but only marginally succeeded in mass producing architecture.

Citrohan House representation (1920)