- Abstract In this research a graph-based methodology has been developed to support modular building design. A graph-theoretic algorithm is used to decompose the design into modules that facilitate the future replacement of building components, allowing buildings to be more easily adapted to changing user requirements. The future flexibility of the building is increased by decomposing it into custom-designed modules, containing adjacent components that currently belong to different systems, but need to be replaced at the same time in the future. The reduction and standardization of the interfaces between the modules can also reduce the interdependencies between the activities for installing the building components, which are currently carried out by different subcontractors. It is shown that this approach to modularization increases the flexibility of the design, as well as reducing expected time overruns during project execution. Such overruns normally occur due to the knock-on effects of a delay in one construction activity on other interrelated activities that are carried out by different subcontractors. The methodology is demonstrated through a case study of a residential housing unit.