Préfabrication experiments - 471 - From assembly lines to trucks, ships, trains and helicopters

Manufactured dwellings are idealized for efficiently supplying homes delivered from a factory to any site. Mobile homes built on standard-sized steel trailers were designed, robustly built to be pulled over roads and adapted to common towing devices. Modular volumetric buildings use similar manufacturing principles, without the mobile substructure, and require flatbeds to carry the volumes to their site, where they are lifted to be set into their final position. Cranes equipped with spreader beams, used to strap the modules, make easy work of modular assembly. Both approaches, a steel mobile trailer or an independent volume, are defined and constrained by transport loads and dimensional parameters.

 

Getting these factory-produced buildings to remote locations sometimes requires more complex logistics; Cargo ships can be used for intercontinental transport. Stacked on ships, they can be rolled off or craned onto barges to be brought to ports and then trucked to their final destinations. Rail is also possible, however it is considered less convenient as the modules would have to be lugged to and from rail lines as manufacturing facilities are not necessarily located in proximity to railway networks. 

 

Another form of modular transportation has been imagined to get houses to any location. While impractical, complex and expensive, the dream of flying a house is connoted in many prefab experiments. But is it really feasible ? High-capacity helicopters, such as the Sikorsky S-64 Skycrane, Boeing CH-47 Chinook, and the Russian Mil Mi-26, are known for their exceptional lifting capacities. These helicopters are specifically designed for lifting and carrying loads exceeding 20,000 pounds (9,072 kilograms). A standard modular volume 12feet x 40feet can easily weigh up to 20 000 pounds. While lifting and delivering one unit is certainly possible, assembling a building in this way is unfeasible. 

 

Whether truck, rail, ship or helicopter, modular volumetric construction is regulated by its factory manufacturing on an assembly line which also determins maximum width as in all cases the module will have to be trucked from its production area to a staging area before its final transport. 

Sikorsky S-64 Skycrane (above); Boeing CH-47 Chinook (below)

Prefabrication experiments - 470 - Soft densification and pre-approvals

 

Industrialization has certainly sped up production of every commodity and reduced their cost per unit. In an era of urgency, housing promoters were inspired by advances in manufacturing. In the wake of World War 2, the subsequent population growth and economic boom of the «Trente Glorieuses», suburbanization and development were linked to the automobile’s democratization. Bedroom communities planned with small uniform houses sprouted using assembly line principles. Along with housing, strip malls, and schools deployed similar modular planning methods in a generalized sprawl of mass-produced built form. 

 

Vast building initiatives consumed resources and quickly reorganized the live-work relationship around commuting. The current climate crisis reframes postwar suburbanization's dwelling provision strategies as wasteful and is providing a context for these bedroom communities to be reimagined as land reserves for soft densification in response to the need for affordable housing. As was the case in the first act of suburban building, communities are again turning to industrialization to quickly provide replicable housing types. To skip over some of the time-consuming permitting and planning associated with one-off projects, catalogues of preapproved designs that add-on, retrofit, or provide accessory units on existing tracts are an attempt to increase housing supply and curtail uncontrolled sprawl.

  

The town of Collingwood in Ontario, Canada has initiated a streamlined ADU (accessory dwelling unit) permitting process based on pre-approved designs, financial incentives, and landlord support tools for ADUs marketed as rental units. ADU’s can be delivered to backyards, attached to an existing structure, or included within the main dwelling unit. The designs are intended to ease design decisions and procurement. One of the preapproved designs is a a 516 sq feet modular volumetric unit, a design by Habitat 28 and Attimo Homes, engineered-to-order and delivered to any site circumventing the usual permit process. A streamlined procurement timeline includes client, permit department, fabricator and builder; this type of integrated supply chain of actors can certainly decrease housing supply challenges using industrialized building systems geared toward repurposing underutilized land resources.

Plan of the P50 by Habitat28 and Attimo Homes