Conventional facility management (FM) software tools, lacking automatic synchronisation with the domain and rich semantic modelling, are limited to the simpler querying of manually maintained models. A software system that monitors and interprets temporally changing (internal) building environments and generates related knowledge can better assist in facility management decision making. This paper introduces a non-intrusive building monitoring framework that includes ZigBee sensor network and supporting software agents to provide better building space usage monitoring through software agents based on the belief-desire-intention (BDI) abstraction, exploiting ontology based reasoning to direct behaviour. The non-intrusive method is particular...