Modularity in industrialised timber housing : a lean approach to develop building service systems

Sammanfattning: Modularity has been applied in various disciplines, e.g. manufacturing, computer, cognitive science and education. General advantages are platform thinking and module variants which provide a range of product variants using a small number of components. However, the field has not been fully explored within construction.Sweden has taken a leading role within industrialised timber housing. Much effort has been put in research and development of the timber structural system. Thereby, the building service systems (electrical and HVAC systems) has fallen behind in development. Currently, there are several actors involved, (e.g. consultants, subcontractors, wholesalers) that are individually procured on shortterm agreements. The actors remain in the traditional culture with dispersed views on value. To be able to break this dependency, enhanced industrialised practice for the building services is sought. Modularity is argued to aid in reducing the variation in production, lowering lead times and achieving control of material supply. Through modularity, production control can be achieved and value can be better managed, issues which are prevailing in industrialised timber housing. The purpose of the research is to evaluate the feasibility of modularity for building service systems within industrialised housing in Sweden. The thesis is based on two appended papers, discussing how modularity can be applied to industrialised housing, considering value generation and production control. The research strategy has been to follow previous case conclusions in the design of the next case. Empirical data have been gathered from five case studies ranging from a market survey to a consultant procurement. Five industrial housing companies have participated and data have also been collected from consultants and subcontractors. The results show that influence from traditional culture is particularly evident for the building service systems, as much work is still located on-site and actors in the supply chains act individually to optimise their own values, leading to lack of production control through e.g. faulty drawings. Further, the importance of cooperation within the trade is underlined in order to shield from the protectionism in the building service trade. The implication is the development of industry-wide common modules capturing internal values, and a company driven development process for management of company specific external values. The data have been analysed with a generic set of module drivers and the relation to value and production control, to identify forces for modular division. The findings point out the importance of drawing validation, possibility to isolate the process for parallel assembly and purchasing control through reduction of articles.The general conclusion is to design base module components only comprising necessary systems, which can be adapted to a generic building system. The suggestion is the development of a building service shaft and a building service inner ceiling. The analysis results emphasise the importance of interface design. In this sense are also included interfaces within the process and the supply chain, i.e. between activities and actors in the production process.