Surface samples are collected by wiping surfaces within the building’s interior or structure and are subsequently analyzed using cultivation methods. Surface sampling is suitable for hard materials such as concrete, tiles, plastic, wood, wallpaper, and paint surfaces. To ensure the representativeness of the sampling, samples should be taken from 2 to 5 different locations within the suspected damaged area. The number of samples to be taken depends on the extent of the damage. If microbial growth is suspected on various materials’ surfaces, at least one surface sample should be taken from each material.
For each sample taken from a damaged area, a reference sample can be collected. The reference sample should be obtained from a corresponding construction type and the same material on an undamaged surface. The reference sample must be taken a sufficient distance away from the damaged area. For example, it could be from a different room or floor that serves a similar purpose but is part of the same property.