Prefabrication experiments - 219 - oddities - 10 - GFRP earth covered houses

The evolution of hardening resins reinforced with fiberglass fibers moulded on a variety of shapes is usually associated with boat and naval construction but it was also marginally but iconically adopted by building construction during the twentieth century; branded as the future of construction. The precisely formed panels could be easily bolted together and consequently disassembled to be reassembled in any setting. The glass fiber reinforced polymer construction could furthermore be transported to any context as the panels were lightweight and could be made to be stackable. Many systems employed these panels as both a monocoque structure and skin in an integrated kit architecture. The fiberglass panel technique never percolated into streamlined construction as one could argue that the housing shapes architects developed were more akin to futuristic space-age imagery than longstanding acceptable housing types. The technology however is still used in many products as the panels are simple to manufacture and offer both flexibility and durability.

Green magic homes (see https://greenmagichomes.com)  has repurposed the twentieth century technology as the basis of an earth covered housing structure where the shell topography onto which the berms are formed is assembled from waterproofed GFRP panels. The panels are moulded and crafted to any shape. Each arched panel is manufactured for a specific design and juxtaposed in all manner of vaulted configurations, from the simple barrel vault open on each end to the very complex organic vaulted structures that could lead to various directions like a network of natural cavernous spaces. The process is quite straightforward. The shaped panels are bolted and glued together over a raft reinforced concrete foundation to create an overall berm shape. Subsequent to their extrados surface’s waterproofing, an arched berm structure is stepped and filled with cellular lightweight concrete to reinforce the shell structure and minimise backfill. Any type of vegetation could be planted over the structure as it is covered with conventional green roof compositions. Essentially, a berm mould, the panels’ intrados surface could simply be painted and exposed on the inside or layered with other finishing materials. Combining the thermal resistance of earthwork with vegetation, the green magic kit, reimagines the archetypal pit house for contemporary living. 

Green Magic Homes GFRP panels and green roof

Prefabrication experiments - 218 - oddities - 09 - Diatom expandable house

Early 20th century modernists endeavoured to bridge architecture and housing through experimenting with materials, forms and industrial processes. Within these experiments, low cost housing prototypes came to characterize the architect’s potential role in an industrial society. This inventiveness was fostered from a generative relationship with parallel industries. The industrialization of construction was the basis of new formal and technical expression and a path for the democratization of architecture. Architecture and quality housing would no longer be for the elite but shared among a cross section of all society. This noble quest defined a type of practise which went beyond the clients’ mandate, the architect was an inventor and expressing this newness was his goal.

Richard Neutra, a very well-known modern architect well-versed in this new role, developed the Diatom housing system as a prototype for low cost housing. Neutra explored a strategy for minimal site disturbance, designing a house that would float over any setting. The system was a simple suspended prismatic form. The newness factor came from a cementitious panel made from Diatom; a type of lightweight polymer concrete. Diatom is a fossil-based silica based sedimentary rock that when ground up performs as an analogue to Portland Cement concrete but has a more porous and lightweight constitution; it is in a class of materials known as geopolymers. The Diatom in Neutra’s experimental housing concept was used for casting panels and beams which were then affixed to a steel skeleton.  

The structural system supported roof and floor plates from four centrally positioned prefabricated anchors. Vertical steel masts were anchored to the cylindrical post moors where they were wedged into place.  Roof diatom slabs and floor beams were fixed to horizontal purlin angles suspended from the central vertical masts.  The Diatom beams and panels were cantilevered from the central masts composing roof and floor plates. The diatom house system was designed as an expandable modular kit-of-parts based on the easy to acquire and manufacture diatom components. This abundant raw material would revolutionize building culture. However, as with the project’s many contemporaneous experimentations, none of the advantages, architectural, economical, could be sufficiently tested or produced in adequate numbers restricting the prototype to a one-off experiment.

Diatom system components from CMHC catalogue of systems c. 1960

Prefabrication experiments - 217 - oddities - 08 - The Self-lift building technique

R. Buckminster Fuller famously posed the investigative question: How much does your building weigh? Pier Nervi Luigi, another important protagonist posited that construction was all about lifting and moving things and as such weight should be reduced to achieve economies and eliminate the need for complex machinery in the construction process. Both identified weight as a decisive factor for assessing structural systems and both conceived strategies to optimize the relationship between form, geometry, strength and material use. Nervi’s “tavelone” ferrocement formwork for thin-shell construction specifically reduced both weight and the complexities of large-scale onsite construction. Other systems for eliminating transportation and external construction machines include approaches such as tilt-slab construction. Used in many industrial buildings but made famous in architecture by Rudolf Schindler in (1921) on the Kings Road house, the house’s concrete panels were precast onsite and simply tilted into place. 

Another significant technique is sometimes associated with the Boulevard Lefebvre disaster in Paris. A tall apartment building using the ‘self-lift’ process collapsed and initiated a long debate about of identifying responsibilities for stakeholders in the construction sector. The self-lift building method, a competition proposal, was invented by a consortium of architects, engineers and builders known as the CET (Consortium d’entreprises et de travaux) in the early part of the 1950s. Conceived as an alternative to reinforced concrete construction, the self-lift steel frame could be made to be much lighter and therefore much cheaper. Analogous to tilt-slab, portal frame sections made the full height of the building were assembled at ground level, hinged at their base, hoisted and rotated from their horizontal position using the previous frame as a crane. Each frame panel skeleton included floor beams, columns, and any bracing. Tilted into place the bays were joined producing a mega-box-frame.  The column hinge represented in the image below made it possible to rotate the ten-storey frame into place. Floor slabs were also precast on-site and lifted into place, reducing the need for transportation. Prefabricating elements on-site reduced costs and made the system very economical to build. Also known as the Porte des Lilas building technique for its first successful use it received patents in both France and the United States. 

Process diagrams and column hinge