Prefabrication experiments - 92 - Tall wood buildings

The merits of building industrialization and prefabrication have been related to waste reduction, efficient standardized processes and climate-controlled quality. Prefabrication reduces strain on both human and material resources. While concrete, steel and glass were the flagship materials of modern prefabrication, standardisation and industrialization, wood framing's age-old traditions of pre-cut components evolved into a lighter form of prefabrication. The wood balloon frame and the latter platform frame became synonymous with small buildings whereas steel embodied tall buildings as bridge building techniques were applied to mainstream construction during the 19^th century.

Today, construction and architecture are absorbing issues of sustainability through life cycle analysis, carbon footprint computations or green building strategies. The high- embodied energy production of concrete and steel are being questioned and the traditional techniques associated with tall buildings challenged. Particularly, massive timber construction is determining new directions for wood products in the construction industry. Responsible forest harvesting, advances in adhesive quality and in production methods and the need to reduce our carbon footprint are pushing production of innovative wood building technologies. From glue laminated beams and columns, to cross-laminated timber panels and laminated veneer lumber, wood is venerated as a sustainable building material. Wood products’ embodied energy can be substantially lower than concrete, steel or aluminum systems. Furthermore wood sequesters carbon over its service life.

Massive wood for tall buildings is being explored all over the world. Notably by Canadian architect Michael Green who published «The case for tall wood buildings» exploring massive wood construction techniques. Highlighting the various case studies is the use of cross-laminated timber panels in a type of massive wood panel construction, which compares to flat slab and bearing wall concrete construction in terms of spans and building system dimensioning. The cross-laminated timber panels are a form of hyper-plywood; vacuum bonded stacked layers of orthogonally crossed wood boards produce a somewhat isotropic (three ply minimum) panel from a fibre dependant base material.  Mass timber applied to tall buildings epitomizes the search for dense urban housing combined with an optimized material, an efficient production process and a simple panel and slab construction system. Tall wood is also gaining traction as regulating bodies, forest-rich countries and project stakeholders build the knowledge base for this new type of powerful industrialization for wood construction.

Excerpt from Michael Green's The case for tall wood buildings

Prefabrication experiments - 91 - 3d Printed Buildings

Prefabrication theory has always intended to unite building methods with innovative manufacturing processes.  3d printing is highlighting a new type of manufacturing revolution and defying traditional building modus. Concrete construction in particular is being utilized to examine the potential of uniting this proven material with a relatively new technology. Building with concrete is comparable to 3d printing's additive manufacturing process. Generally a mixture of cement, water, sand and aggregate are mixed to a uniform paste and poured into moulds where hydration hardens the paste to a solid artificial stone-like material. 

Concrete and steel reinforced concrete was unambiguously synonymous with modern building methods as the technique was dependent on the industrialization of both cement and steel production. Concrete’s state change from liquid to solid provoked many experiments by which the material’s malleability was combined with active formwork to improve quality, speed, overall construction efficiency and patterning possibilities.

Thomas Edison’s continuously poured house, the Tournalayer machine for producing houses and the invention of slip forms exemplify a number of processes for simultaneously pouring and shaping concrete. Specifically in the case of Edison’s concrete houses, the two to three story moulds generated complete structures in a single cast. Most innovative and optimistic approaches to concrete construction were founded on a site-mechanization paradigm that still highlights heavy-duty concrete construction today.

Based on open-source innovation, 3d printing technologies are being explored along with concrete production to produce complete complex buildings or large fragments at a fraction of the time or cost that would be necessary with conventional tools. Foster and Partners, a large engineering firm has been researching 3d printed concrete with Skanska an innovative contractor looking to showcase the technology's potential.

The additive process is taken even further by an organisation known as WASP (World’s advanced Saving Project) who has been developing and researching with giant 3d printers such as their Big Delta; The 40 ft. tall printer uses a robotic arm equipped with a mechanical mixer, which combines material into a paste and extrudes it through a nozzle. The nozzle deposits layer upon layer of material in a precisely digitally controlled pattern, extruding shapes as the layers build-up. As 3d printing technology is brought to mainstream building, Edison’s dream of a one-cast concrete house seems almost conventional.

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Prefabrication experiments - 90 - Kisho Kurokawa's Apartment House

Applying the theoretical model of factory production to architecture has had its proponents all over the world and throughout modern history. Regarded as the future for mass housing, the union of quality and quantity in matters of building production was founded on the principles ascertained by Henry Ford’s production line or Frederick Winslow Taylor’s scientific management methods. Applied to building construction, these theories gave modern architecture its radically industrial language and transformed design from stylistic historic imitation to grid-based systemic modular arrangements.

Although first modernists endeavoured to industrialize building, it was the Japanese metabolists, due to the necessary post-war reconstruction of Japan that sustained and furthered the early 20th century avant-garde’s dreams of quantity, functionalism, modularization and adaptable planning. 

As covered wagons and then automobiles were the models of manufacturing in the U.S.A., Japan’s industrialized aesthetic potentially bears some traditional roots in mobile capsule-like (Kago) people movers. The capsule was the ultimate form of flexible and agile architecture. The capsule, however, was only part of this meta-strategy for building. The basic component was the megastructure as a support system for the small functional plug-in units. Architectural experiments by Kisho Kurokawa exemplify the ideals forged by this movement, which united modern values along with post-war space-age predictions. The prefabricated apartment house Kurokawa designed in 1962 as an experiment foreshadowed his later designs for the Nakagin capsule tower or even the more ambitious Takara Beautillion for the 1970 universal exhibit. The three projects, built or un-built, demonstrated the plug and play nature of this product architecture.

The apartment house project included an infrastructure of precast concrete components and integrated functional glass fibre reinforced plastic shell capsule units for baths, kitchens or storage. The overall spatial structure composed of panelized walls and slabs was assembled with mechanical joints simplifying construction and any required future disassembly. The open frame structure was designed to receive the functional capsule units akin to bottles on a rack. Although repetitive, the megastructure and capsules' clustering was suggested in an asymmetrical pattern. This sensibility toward an overall dynamic plan arranged on standardized components showcased Kurokawa's sensitivity for achieving quality spatial relationships as well as an efficient industrialized building system.

Architectural model photographs

Prefabrication experiments - 89 - Stick Frame Panelization

The continuing effort toward the development of industrialized housing and building systems was and is held back in North America by the relatively low-cost manufacturing and construction of wood (stick) framing. The uninterrupted production of small components combined with simple construction methods prevailed over the highly symbolic and innovative potential of plastics, reinforced concrete and modernity's emblematic material: steel. The conventional balloon frame and the more recent platform frame integrated the benefits of mass-production with the convenience of on-site building. The wooden «two by» stud was to filigree construction what the clay brick was to masonry construction: a prefabricated modular building unit leveraged toward infinite options. It remains difficult for systems with greater costs and less flexibility, however innovative, to compete with stick framing.

The on-site accessibility, flexibility and adaptability of light wood framing along with its low-cost overshadowed its shortcomings in terms of quality control, waste and resource, both manpower and material consumption. Uniting stick framing and factory production of sub-systems through panelization of stressed skin wood framing has been experimented with and through today's information technologies is developing into a formidable industrialized building system offering the advantages of continuous production with the accessibility of stick framing. 

Factory automation allows wall panel composition, manipulation, manufacturing and quality control to be completely digitally verified reducing waste and enabling each panel to be designed and manufactured according to specific project designs. This mass-customization model of production is being reinforced by applications such as Autodesk’s Timber Framing, which make the design to construction process transparent. Noteworthy companies such as One Build (http://www.onebuildinc.com) are organizing their business models around panelization and are promoting flatpacked panels to further reduce the transport inconveniences associated with modular building. Although panels require more site intensive construction they also make weather tight on-site stitching easier to control. 

Panelized structures involve a margin of buildings produced today in North America. As technologies reinforce the customization of industrialized building components, the negative connotation of standardization is being replaced by the value of flexibility.  This value-added nature of the panel could be further optimized to integrate other building systems (hvac, electrical) and a more systematic approach offering homeowners greater knowledge over the life cycle costs of their buildings. 

Autodesk's Timber Frame App - screenshot