Prefabrication experiments - 514 - Cooperation - advantage or inconvenience

 

The advantages of offsite construction are chiefly articulated to preparing components in advance of their use in a controlled setting for their subsequent delivery and assembly on site. Preparing sub-assemblies in a factory leads to potential gains in quality as acknowledged impediments to conventional construction are mitigated: climate, health and safety hazards, supply chain tuning and greater collaboration between designers and producers. This last aspect is often cited as a challenge to increased uptake in offsite construction, which relates to how comfortable the construction sector has become with the entangled mess that is onsite building. 

 

Cooperation between trades, design professionals, general contractors and manufacturers generally leads to better projects whether on or offsite built. However, when it comes to producing elements in a factory this close cooperation is necessary to ensure a streamlined chain of decisions that overlaps with conditions that are proceeding onsite. These conditions become difficult to adapt to with a manufacturing process if site situations change from those initially planned.

  

Integrated project teams or even design-build teams are more conducive to onsite/offsite cooperation as they provide the upfront planning and collaboration required to ensure that all technical aspects are precisely coordinated before the project begins. Mistakes and errors in factory production arise but can be corrected in the factory before sending parts out to the field; however discrepancies between field conditions and production are extremely costly to repair onsite and can lead to long work stoppages and cost overruns. 

 

While the intensive planning and collaboration phase can be time consuming when evaluated against the conventional design-bid-build process, it should not be seen as a challenge but as an opportunity to achieve much higher quality reducing wasteful onsite adaptations.

 

Generally, the type of necessary cooperation can be maintained by keeping lines of communication open between all parties and sharing proper documentation and shop drawings that detail elements that will be delivered to the field along with their required stitching details. Digital virtual modelling can certainly facilitate this process but it’s not a panacea and must be accompanied by adequate and continuous communication between all parties involved.

 

Off-site and On-site logistics from Zhang, C., Jiang, J., Xia, C. et al. Dual-objective optimization of prefabricated component logistics based on JIT strategy. Sci Rep 14, 31267 (2024). 

Prefabrication experiments - 513 - Junior Trelement industrialized building system

 

The endless battle of standardization versus customization, a longstanding obstacle stinting the uptake of industrialized construction, has often guided the conception and promotion of open systems capable of bridging the conceptual gap between a cost-effective required seriality and ingrained configurational agility. Design flexibility becomes an advantage and a selling point for the commercialization of these industrialized construction systems as demonstrated by Alco Germany's Junior Trelement kit of aluminum pieces, patterned on adaptable grids implemented in one-story facilities, first in Germany and then throughout Europe. 

 

Advertisements and the published product catalogue describe the early-1970s platform as a solution for personalized affordable manufactured architecture for everything from schools to office buildings and to single-family dwellings. The system's aluminum frame was regulated by a triangular grid, with connecting beams forming a hexagon geometry of roof joists attached to a six-pronged plate; this configuration shaped the basic polygonal composition. Available in rectangular as well as the triangular arrangement described above, the Junior Trelement structure spanned approximately 5 meters. In the triangular version - each equilateral module had a segment length of 2,3 or 2,5 meters. The intersection plate at maximum spans sat on an aluminum column or post whose cross section mirrored the connector's star shape.

 

Ideally suited to single-storey buildings, the Trelement horizontal plane roof could be tessellated to create coverings of any shape and size. Still marketed today, the company also promotes an after-sales service for existing buildings constructed with the system - foregrounding the advantage of repairability and replacement of existing parts. 

 

This type of systemic circularity is embedded in Trelement's DNA as well as its aluminum parts. Marginally applied in buildings due to fire constraints, aluminum's malleability specifically its capacity to be extruded in very precise shapes or profiles - makes it an ideal material for this type of time-based adaptability as elements can be put together and disassembled multiple times without fatiguing. Further each piece is theoretically interchangeable with those of any other building made of the same components, establishing a potential trading network of Trelement parts harvested from disused, disassembled buildings. 

Alco's Junior Trelement System

Prefabrication experiments - 512 - A prefab «sweet spot»

 

Growing global interest in prefab raises interesting questions for its future development: do systems define an era, or do eras inform a need that breeds a particular system? Light timber framing for low-density residential construction, heavy centralized panelized precast concrete to rebuild Europe, and integrated modular volumetric systems, known as MIC (modular integrated construction) in various contexts recount and symbolize a period's dominant framework for streamlining building construction with manufacturing. Mobile homes or steel skeletons for industrial hangars have somewhat less generalized histories but are equally emblematic. Today, comprehensive factory production remains elusive, but building culture is overwhelmingly mass-produced and standardized, attuned to materials and methods that are aligned with an onsite/offsite sweet spot. 

 

The mechanized sawmill in the US which led to balloon framing, required fireproofing for dense urban architecture in Europe generated patents for the reinforced concrete flat slab system, and panelization in particular illustrate success stories of Industrialized building systems balancing strategies with project functions, scales and socio-economic criteria: timber panels have been massively adopted to accelerate construction. Integrated (closed) panels or structural frames (open panels), for walls, floors, and roofs reduce sitework and waste without the predetermined architectural language associated with modular volumetric or comprehensive proprietary factory production. Their variability is an asset; architects can design any configuration that is translated as «panelized», produced as flat-packed building surfaces, delivered just-in-time, and assembled in an orchestrated sequence to facilitate construction management.

 

The adoption of this type of prefab for single family as well as multi-unit residential construction up to a regulated maximum of six stories (in Canada) showcases the industry's capacity to auto-regulate and adjust to technologies that can be introduced into construction's fragmented process without substantially altering it. Kitchen cabinetry, modular roof truss frames, prefabricated cladding systems, precast architectural panels, and curtainwalls all represent a similar manufacturing «sweet spot» suited to a traditional construction process: a seemingly seamless coordinated  on and off site production process applying rigorous manufacturing criteria, assembly details, and principles – examples of DfMA applied to buildings. 

 

The construction industry evolves slowly, with ingrained challenges related to productivity, transparency, and trade entanglement. However, panelization shows the sector’s ability to integrate nimble strategies that hit a sweet spot where advantages for design and fabrication become obvious to all stakeholders.

open (left) versus closed (right) panels

Prefabrication experiments - 511 - Design for Disassembly Before its Time - Jean Prouvé's Maisons démontables

 The confluence of military rigour applied to construction management, design methodologies and generational investments in housing encouraged inventivity in building systems. Manufacturing advances outpaced onsite construction producing a myriad of components for the rapid erection of diverse building types. This spirit of production for assembly spawned new experiments and their foundational industrious professional practises. Further, materials as well as methods associated with war efforts and their subsequent transfer to civilian use supported an integrated industrial design process applied to architecture, foreshadowing DfMA approaches promoted today.

 

Metalworker and self-taught industrial designer/architect Jean Prouvé’s work personified this generative triad of crisis, industrialization and the impulse for manufacturing in architecture. Responding to postwar government mandates, Prouvé developed a series of service core houses «for better days». His vision for the serial production of houses steered Prouvé to design and fabricate building kits with dimensionally coordinated metal parts for structural frames infilled with glass and timber panels in a type of multifunctional curtain wall system.

 

Included in a highly productive career, Prouvé explored the theory of demountable buildings arguing for an open-source architecture that could be mass produced. Articulated to his 1-meter grid, the demountable building kits integrated a mature approach for scalability linked to part interchangeability; with pieces, details, assemblies and repetitive patterns for overall systems harmonized for simple arrangements. From his 4x4-meter military shelter designed first as an armed forces or emergency dwelling and then as a leisure unit for a budding post-war prosperity to examples designed for their disassembly developed for specific functions, the reversible elements could feasibly be used, reused or repurposed for the repair and replacement of parts. 

 

These early discussions around flexibility and adaptability evolved into contemporary strategies for circularity, component standardisation, and optimizations for interoperability. The simplicity of Prouvé’s demountable structures would not be as straightforward in today’s performative and normative building culture, however the underlying ideas are certainly being revived as our contemporary crises call for action to reform how the built environment is produced, managed and repurposed. 

An example of the Demountable Houses