Prefabrication experiments - 138 - settings - 9 - Lean manufacturing - the Toyota model

Over a century after the dawn of industrialized building, modular and offsite construction appear to be going through a third renaissance. Applying factory production principles to home building is hardly a new experiment as Henry Ford's theories initiated a compelling connection between architecture and the factory. Using the assembly line to produce enormous quantities of goods while increasing quality and reducing consumer costs required a revolution in every level of manufacturing from design, engineering, procurement, assembly and supply management. The Ford model was based on continuous production and a capacity to move inventory. Applying automobile production schemes to manufactured housing lasted through much of the twentieth century as the prevailing pattern particularly in the production of mobile homes. 

The 1970s and 1980s brought a revolution to factory production enabled by another giant of the automobile industry, Toyota. Endeavouring to improve efficiency, the Toyota Company focused on task performance as a gauge for overall output quality. Known as «lean manufacturing» the strategy is established on all components being delivered and assembled as they are needed. This more immediate method reduces waste and the amount of stocked inventory.  Lean production is defined by five ideologies: just-in-time production, automation (jidoka), low inventory (Heijunka), standardized components and employee collaboration (Kaizen). 

Applying the lean model to housing, the Toyota Housing Corporation builds light steel volumes, which are 85% completed in the factory. 28 different volume types are available. An average size house requires approximately 11 modules. The cellular construction system is based on stacking and stitching the large components together on site. Akin to large building blocks that are snapped together, the entire process form order to assembly can be as short as 45 days. Although not the largest producer, the Toyota home brand is coming into its own as one of the important home producers in Japan.

Toyota's business model functions on the same basic principle of the pattern book shared by many manufactured home companies. If the production model is highly efficient, the designs remain fairly conventional. Recently partnering with architects the company has established a line of contemporary models perhaps looking to achieve the same brand recognition as MUJI has established with partner architect with Kengo Kuma.

Stacking and stitching Toyota House modules