Integrated design was devised during the Second World War to speed up the development and
construction of new complex weapons. It proved to drastically reduce the time to market and
product development costs, while delivering superior products. It is why it was widely adopted
by the manufacturing industry in the 1980's. Integrated design was only introduced in
construction in the beginning of the 1990's for the design of sustainable buildings to solve
problems in the sequential design process, which was generating sub-optimal buildings at higher
costs. This proposed new design process shares with sequential design and delivery the
breakdown of the project lifecycle into a series of phases marked by milestones, during which
interim deliverables (brief, concept, preliminary design, working drawings) are reviewed and
approved. It differs in the organization of the work to produce these deliverables. In a sequential
process, problems are distributed among people that work and develop systems in isolation.
They meet only for coordination purpose. Members of the project teams will change from phase
to phase. There is little opportunity for optimization. (Larsson 2002).