This paper presents an automated code checking system (DesignCheck) that enables quick and easy compliance assessment against building codes and assists designers in finding potential problems early. The system enables modelling of extended design information and encoding of a wider range of domain knowledge embedded in building codes. It uses Industry Foundation Classes (IFCs) as a common model to transfer 3D object-based CAD models to the DesignCheck internal model. The DesignCheck internal model allows for the definition of comprehensive design information as well as identical description mapping onto building codes. Building codes are interpreted using an object-based representation and then encoded into object-based rules using Express language. A geometry engine and semantic interpretation are used in the DesignCheck system to support design performance verification. The system allows for checking designs at the different stages – sketch design, detailed design and documentation. It enables the checking of building models against individual clauses within a building code, or alternatively, checking individual object types or group of objects rather than the entire building model. Once the checking is completed, the interactive reporting interface offers a variety of viewing options and enables the user to input the required specifications of objects. The first code to be implemented is the disabled access code.