Prefabrication experiments - 486 - The Patterns of Timber Framing for Teaching Robots

 

Envisioning the streamlined fabrication of customized pieces, panels, or chunks delivered just-in-time, for the quick, and easy assembly of a house or building has been the ambitious value proposition of many industrial protagonists. Some have succeeded in harmonizing their business model with a localized specific demand; however, the more generalized industrialization of construction required to increase productivity and respond to the growing challenges of onsite construction is still elusive. The required reform toward production in construction, is all-encompassing from the small onsite contractor to the large developer. The industry is too bogged down by old habits; manufacturing requires upfront investments that make it difficult to compete in terms of costs and agility with conventional builders. 

 

A startup based in Alberta, Canada, is striving to reform the prefab producer’s business model based on a completely integrated Factory Operating System that deploys lean robotic production to streamline the framing of house panels for floors and roofs. Promise Robotics is looking at prefab in a new way by understanding how robots can be taught to assemble project specific and industry standardized framing patterns, in a just-in-time factory-to-site delivery process. A relatively small production bay is controlled by the file-to-machine data-driven process. The robotic arms can switch from lifting, cutting, placing, aligning, nailing, seamlessly executing machine learned patterns orchestrated to produce a 40-foot wall framed panel in 8 minutes. 

 

Two robotic arms working in conjunction, borrowed from the automotive industry, were set up to learn from a local manufacturer's production process and endeavor to reproduce timber framing in idealized AI-driven conditions. From this research and development, the company is proposing to market agile «flying factories» all over the country to help increase supply and encourage the adoption of new prefab ideas. Recognizing that housing construction is not only a production problem but includes material management, supply chain harmonization, and factory to site logistics, their value proposition includes an operating system that outlines and manages every part of the process, including the choreographed robotic assembly of wall components. 

See article in  https://www.canadianmanufacturing.com/manufacturing/promise-robotics-opens-new-homebuilding-facility-in-alta-312995/

 

Prefabrication experiments - 485 - On- and Offsite management

Dealing with difficult climate conditions, labour shortages, or even health and safety issues on building sites seems to point toward greater offsite uptake as an obvious solution for improving construction's productivity and efficacy. The enduring fragmentation of the sector made up of many small contractors and trades managing their projects on a one-by-one survival-of-the-fittest model has led to a construction industry that is not only conservative but is refractory to any type of change or innovation. Buildings in general still go up inefficiently the same way they have been for the past hundred years and industrialization, while promising an integrated model for producing other commodities, has led to a disjointed process isolating designers from fabricators and builders.

 

Construction has become about managing disparate subtrades and coordinating an onsite entanglement of systems or tasks, that,  at best is ordered by a proficient general contractor or at worst a convoluted mess of discordant contractual relationships. While the building industry’s fragmented culture is difficult to shift on a dime toward harmonized practices, one of the current drivers for reform is the impetus to efficiently respond to the environmental crisis, by reducing waste and gaining any competitive advantages linked to streamlining potential efficiencies.

 

This potential swing toward reducing waste is where construction management and offsite fabrication can be tuned to operate in a just-in-time symbiotic relationship to deliver value added subcomponents. The pre-assembly model is different from basic modular volumetric or panelized systems as it is based on what makes sense to prefabricate and can yield greatest results in terms of time management. The overlap of onsite and offsite tasks is an untapped opportunity to apply manufacturing principles to construction. The constructor-manufacturer integration model also presents challenges, as traditionally companies have specialized in one or the other. However, the benefits of managing tasks ideally suited to their off- or on-site conditions can create a different type of prefabrication company based on managing project processes rather than completely separating construction and manufacturing, which only leads to further entanglement of stakeholders.

Just-in-time delivery of a preassembled chunk

Prefabrication experiments - 484 - Competitiveness and Timesavings

 

Advanced manufacturing, big data optimizations along with precise resource management are all combining to generate all manner of efficient fabrication and labour-saving production processes. This is the case in nearly all sectors. Why haven’t these translated to a competitive edge for prefabrication deployed toward building construction? This simple question relates to offsite construction and manufacturing requiring different cost structures, an enduring obstacle to a sustainable uptake. Most agree, prefab reduces timelines; if time is money, prefab should be much cheaper when compared to onsite conventional construction. Time savings have not necessarily translated to economies on one-off projects. Higher upfront planning costs, greater factory overhead, entanglements caused by on- and off-site coordination and steep learning curves for inexperienced stakeholders can increase overall expenditures.

 

When compared to other manufacturing sectors where industrialization has optimized quality, while reducing time and costs per unit, architecture remains bogged down in singular prototypes. Each building includes far too many contextual specificities to justify the mass production flows required to consistently lower costs. Replicating details, components, processes over multiple projects can present opportunities for bulk purchasing and regulating supply chains, however, varying loads, soil conditions, environmental constraints, management requirements in dense urban areas, ever-changing stakeholders, and code obligations all differ from one site to another occluding stable demand for normalized designs that would induce important savings.

 

Notwithstanding the one-off contextual intricacies, reduced timelines should still translate to savings in overall project costs. A condensed schedule of even a modest 10-15% on a standard timeline can minimize interest payments on loans, site management costs like heating for winter conditions, equipment rentals and even deliver earlier earning potentials, an important advantage in housing or production facilities. A structured global cost analysis and comparisons should be applied to offsite construction by including some type of time equivalent factorization. The archaic nature of onsite construction is still mired in analysing construction costs in terms of management, labor and materials. Reforming costing methodologies is one of the important cultural shifts required to increase offsite construction’s potential market penetration.

Extracted from https://www.ellismodular.com/why-modular/ 

Prefabrication experiments - 483 - Constant, stable purchase order pipelines

 

One of the most important differences between the on-site subtrade or contractor and the off-site manufacturer is the need for consistent purchase orders with similar characteristics; A constant portfolio (often referred to as a pipeline) is required to cover important investments in everything from marketing to tooling, all essential for high quality and quantity fabrication. 

 

On-site contractors benefit from logistics that are defined and managed according to a single project. Specifically in a conventional design-bid-build process contractors estimate and then purchase all specified elements to build a building and their risk is limited to these purchases. Risk is also mitigated by the fact that any cost overruns that are incurred because of omissions or unforeseen conditions will, in the end, be assumed by the client. 

 

Along with all the same functional, technical and economic criteria of an onsite project, off-site fabricators need to amortize costs over repeated productions. This creates conditions that constantly challenge the economics of high-value-added prefabrication. The bipolar objective of responding to a client’s one-off prototype criteria while managing large overhead costs of manufacturing is completely foreign to onsite builders and thus defines the lack of competitiveness of offsite versus onsite at least when it comes to delivery of one-off projects. 

 

Offsite manufacturing can only be economically feasible if project pipelines permit advanced planning and resource management to justify just-in-time flows that balance sales with bulk purchases. When comparing the bidders' supply chain between two competing companies, one onsite and one offsite, the overhead required to sustain the prefabricator’s advantages, compared with the jobsite contractor who assumes lower overhead linked to project specific tools and materials, is difficult to overcome. Further, materials for the onsite contractor are paid for as claims progress on site. 

 

Unstable demand that does not sufficiently replicate certain elements will never be a viable avenue for off-site construction, if the objective is to reduce costs. The crux of the problem is that ingrained architectural singularity occludes the potential for large-scale project pipelines - this simple but hard to crack polarity has spelled the end for many promising prefab experiments.

Similar characteristics in manufacturing of modular volumetric

Prefabrication experiments - 482 - Aligning Stakeholders for prefab's success.

 

Repeatable, iterative processes, gaining value from each outcome, and replicable designs are the basis of off-site construction's potential successes. The factory production of complete houses, of large modular volumetric chunks or panelized building segments require a harmonized supply chain contingent to purchasing and investing. Capitalizing includes everything from infrastructure and machinery to software and skilled labour, all optimally managed to gain sufficient efficiencies to outperform on-site construction. 

 

While these expenditures have been the basis of making products since the beginning of the Industrial Revolution, building construction is complicated by the number of parts and systems that need to be synchronized. Certain tasks simply can’t be accomplished in a factory setting: civil services, foundations, and site work. A building will therefore always require two types of construction stakeholders: the offsite manufacturer and the onsite contractor. Maximizing upfront planning and carefully pinpointing exclusive and shared responsibilities for both is not an easy task, especially in a conflicting building culture. 

 

The offsite manufacturer is often responsible for supplying an assembly of materials that is systemically incomplete. Its on-site completion involves other contractors, sometimes multiple subtrades and this is where prefab can lose some of its advantages due to wasteful overlapping that is not meticulously rooted out. Further, investing in a factory, production machinery, marketing departments, lifting and moving equipment also imposes greater costs to the prefabricator when objectively compared to a contractor with a small team that receives their materials as needed and paid for them earlier, as materials are considered installed once they are delivered to the construction site. 

 

These challenges for manufacturers drive the requirement for a portfolio/pipeline of similar types with replicable characteristics to spread planning and operational costs over multiple projects. Design modularity, task repeatability, and component interoperability are ways to achieve success in prefabrication. Unfortunately, an irrational quest for singularity is entrenched in architecture, even for repeating types like housing. Buildings already repeat a certain number of elements and details that can be outlined, described, and regulated; however, the fragmented nature of construction has been shaped to repeat the same wastefulness repeatedly. 

Idealized process - published by Canadian Homebuilders Association
https://www.chba.ca/factory-process/

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)

Prefabrication experiments - 477 - Prefab as policy

 

Catalogued designs, uniform platforms, replicable buildings, preapproved prefab micro dwellings - governments are scrambling to test many of these ideas to supplement affordable housing supply faced with a stagnating construction sector. Offsite construction complements these approaches by applying manufacturing methodologies to increase efficiencies and capacity. While some see current crises as prefab's heyday, the possible links between manufacturing, architecture and housing construction already sustained modernism a century ago. 

 

Modern architects explored and elevated prefab to a type of language spawned through material innovation, redirecting architectural production from the onsite fashioning of materials to the streamlined assembly of factory-made components. From relationships with military industrial complexes, governments also underwrote prefabrication as a way forward toward stimulating inventive systems. Prefab’s time came and went in the 1940s, 50s and 60s with each generation explaining why their era was the right time for a robust turn toward industrializing construction.

 

Going from architecture and construction as a cultural phenomenon based on centuries of onsite informalities and peculiarities to industrial production tainted by mass production connotations is a transformation that requires more than simple reforms - it requires a complete conversion of business models for builders that are ingrained in business-as-usual and apprehensive about the expanded economic risks that go along with mass production. These changes are even more tenuous as demand for and successful application of offsite construction as a product-based pattern is constrained to certain relevant building types with repeating organisations. 

 

Iconic experiments like the Lustron House, designed by Carl Strandlund, convey the rich heritage of government support along with ambitious inventors looking to produce coordinated components for easy-to-assemble low-cost housing. Their application was largely obstructed by onsite principles promoted by tract housing developers like William J. Levitt who took simple to build platform or balloon framing and democratized onsite mass production processes that were ingrained with complete flexibility.  Lessons from both production methods tell the tale of prefab's marginal uptake and consumers' enduring need to feel that their home is a one-off process, even though all its components and properties are mass-produced.

Onsite construction using mass production principles