Microbial organisms such as bacteria, fungi, and algae significantly contribute to the defacement and weathering of masonry construction materials. The growth of these organisms and the severity of masonry defacement and biodeterioration are dependent on many factors, including porosity of the material, pore size and distribution, permeability, pH, nutrient availability, presence of light, available water, and temperature.

Physicochemical properties such as porosity, pore size distribution, permeability, surface charge, and alkalinity differ with each masonry material. These properties often affect the performance of biocidal treatments applied to the surface.

This article discusses a study that was conducted to determine performance and application-rate ranges based on the response of treated masonry substrate materials facing a microbial challenge.