Ceramic building material is a useful passive modulator of the environment. The subject area is based on traditional cultural and material knowledge of clay properties: from amphora to rammed earth building; and ranges to present uses: from desiccants and space shuttle tile patterns to bio-ceramics. The primary consideration is to control material density and porosity in a tile component, in response to specific environmental conditions. This depends on a number of key physical principles: the ability of the material to absorb thermal energy, the ability to absorb and then ‘wick’ moisture within the pore structure, and the decrement factor or ‘time lag’ of the effect. The interplay between these properties point to the importance of directionality in the porous microstructure, at the boundary layer. Material characteristics have been investigated in the laboratory at a micron scale and in the ceramics workshop at full scale, with some interplay between the two. Recent work done on monitoring has led to the development of software tools that allow feedback (approaching real time)- a visual representation of the dynamic thermal and hygrometric properties involved.