Building material has been one of the aspects in architecture that directly relate with the overall building performance. Nowadays, porous traditional building material, such as bricks, stones, concrete, is still preferred due to its performance of porosity that supports passive cooling and reduces the building’s energy consumption. However, the porosity of building material could also cause many problems, such as damp, fungal and moss growth, that could cause deterioration of the building leading to the practice of coating. This paper questions how the act of coating often seen as a way of keeping the building in perfect condition with disregard to the building material’s porosity. It investigates how the different mechanism of porosity in building material in turns triggers a different act of coating. Furthermore, this paper argues that the act of coating should consider the performance of porosity to achieve a better building performance, not just regarding the energy efficiency but also the ecological sensibility towards the environment.