Prefabrication experiments - 196 - current practices - 07 - Prefabricated timber and straw bale panel construction

The return of prefab as an essential theme in construction relates to systemic low productivity, ecological imperatives and undoubtedly to changing demographics. Both work force and qualified labourers are becoming rarities in industrialized countries. Maintaining and increasing productivity in the context of rarefied labour commands inventiveness in matters of materials, methods and in the use of contemporary tools. Traditional construction trades are no longer the heart of the construction industry. Remarkably, however, as a demand for sustainable building strategies intensifies, vernacular construction methods are being reconsidered within a factory setting.  Rammed earth or even straw bale construction, although not habitually related to prefab are being produced in factory settings to reintroduce the benefits of using these natural construction techniques without their intensive labour constraints.

Blending contemporary tools and factory production with traditional construction techniques is the basis for a long-standing 1.8 million Euro research partnership between The Department of Architecture and Civil Engineering at the University of Bath and Modcell. Modcell is a company established about 200 km west of London whose main objective is to demonstrate the ecological potential of straw bale construction. The ongoing research has led to a series of experiments employing a low embodied energy factory produced and hybrid modular building panel with varying depths from 262 mm to 377 mm to 427mm. The prefabricated panels blend the structural capacity and precise nature of timber stud construction with the performance of thick compressed straw blocks inserted within the timber cavity. 

Prefabricated locally or in what is being termed as flying factories (varying contexts and temporary), the panels’ frames and straw bale infill are flat packed, transported, assembled and layered with a breathable battened sheathing, ready for any type of cladding or interior finishing to be installed on-site. The resulting wall issuper-insulated, and employs renewable, locally sourced, carbon sequestering, sustainable building materials: a perfectly sustainable and perfectible prefab solution. The standardized construction details for walls and roofs are designed for quick assembly and disassembly. The first experiment undertaken with the University of Bath was disassembled, reconstructed and adapted for a different site and use. The highly thermal resistant panels combined with weathertight detailing can meet the PassivHaus standard requiring little energy for heating or air-conditioning.

Modcell straw bale and timber panel - from the company website

Prefabrication experiments - 195 - current practices - 06 - The Move-Home

According to the UN, 68% of the world’s population will live in urban areas by 2050. This projected urbanisation places an ever-increasing premium on serviced land to be developed for housing, schools, infrastructure, etc. Each square meter is wrung searching for affordable dwelling solutions. Affordability often equates to building smaller stacking and loading additional units on a piece of land. While this increased density is seen as an asset for sustainability, flexibility and adaptability of urban living spaces is being lost, as usage is increasingly determined. 

Addressing flexibility is at the heart of a mechanical and mobile service core designed and produced by architect Pierre Leclerc in a suburb just a few kilometers away from Montreal, Canada (the home of Habitat 67). The move-home, a moving hub for a transformable dwelling combines in a relatively small footprint, kitchen, bath and technical services. The service module is attached to a continuous track and rail system that easily glides the unit in order to gain more or less living space according to changing daily needs. Moved at the push of a button, all plumbing is based on a pump system that follows the unit as it moves, and water is pumped to and from a fixed vertical stack, which is the only element that pierces through the floor structure. The system's water and power usage is monitored and can be controlled according local bylaws to determine energy consumption. 

Each unit is equipped with motion detectors and a security kill switch to stop its motion in the event of an emergency. The unit is available in different configurations and is currently being produced to equip micro units, but could be adapted for any existing or new construction. The typical organisation divides two spaces, sleeping and living. The murphy bed in the bedroom can be lifted out of the way and the unit slides to increase the living area. Foldable furnishings attached to the storage wall could be used as desks, tables and create spaces for various uses.  A moving service core, the move-home is a contemporary interpretation of metabolist capsule towers or displaceable living tailored to identify with an ever-changing marketplace. 

From the company website, Move-Home configuration

Prefabrication experiments - 194 - current practices - 05 - Protohomes' Hyperspace and Protocore

In the early twentieth century, technology played a fundamental role in developing a factory-made architecture or more specifically an industry, which would produce homes with the same efficiencies as automobiles. Surrounded by a revolution in manufacturing most modern architects set aside part of their time to contribute, explore, construct and determine the future of dwelling production. The separation of served and service spaces is one of the modern principles developed to facilitate the incorporation and arrangement of new technical needs, components and conveniences. Today, information technology, digital fabrication and their accessibility are driving a new era of prefab experimentation. Alternatives to the basic on-site stick building that overtook many other methods during the latter half of the nineteenth and the first part of the twentieth centuries are being challenged.  Protohomes, a California based company, founded by architecturally trained Frank Vafaee in 2011 is proposing homes that utilize and assimilate contemporary methods and information technology to showcase new prefab potentials in the housing sector.

Protohome’s housing strategy is based on the very modern idea of served (hyperspace) and service (protocore) spaces. Separating technical spaces from living spaces opens up the home, letting it evolve and adapt from current patterns to future configurations as the plan is unconstrained from structural or technical components. The Protocore is the power unit of the home; a contemporary service core or hub, which includes all electrical, mechanical, infrastructure and plumbing elements. Read simply as core and adjacent spaces, this strategy is not very different from what many architects have tried, however the company uses BIM based modeling to link design to fabrication to on-site assembly. Their Integrated Component Based Assemblyis a process by which all the houses components and pieces are virtually predetermined and included in a large company catalogue which can serve multiple house typologies based on an evolving kit-of-parts. Construction elements and materials remain fairly conventional, while the innovative modeling process should alleviate the entanglement associated with on-site construction. An integrated manufacturer, Protohome’s business model is driving a new type of off-site construction where technology and BIM modeling act as a harmonizing tool for a more streamlined home delivery.  

Proto Core - from the company website