Surface sampling collects mold samples directly from building materials and surfaces to detect settled contamination and identify affected areas requiring remediation. This method determines which specific materials harbor mold growth and quantifies contamination severity.
Sampling Techniques
Surface sampling uses three primary methods: swab sampling with sterile cotton applicators moistened with distilled water; tape lift sampling with sterile transparent tape pressed onto surfaces; and vacuum collection using HEPA-filtered samplers. Each method is applied to a defined area (typically 100 square centimeters) of suspect material including drywall, insulation, wood framing, and ductwork surfaces. Samples are cultured on selective media and results are reported as CFU/cm² to enable comparison across different materials and locations.
Significance in Assessment
Surface sampling maps contamination distribution throughout affected areas, identifying hidden mold within wall cavities or HVAC ducts that visual inspection alone cannot detect. Results determine which materials require removal versus cleaning and guide containment barrier placement during remediation. Post-remediation surface sampling verifies that contamination has been eliminated before areas are cleared for reoccupancy.