Mold Remediation Techniques
Domain focus
The mold section tests IICRC S520 principles: condition assessment, containment, source removal, and post-remediation verification (PRV). Questions often combine a moisture reading with a containment decision.
Core rules
- Condition 1 = normal fungal ecology for the location; Condition 2 = settled spores with no active growth; Condition 3 = actual mold amplification. Condition 3 drives containment and remediation.
- Correct the moisture source before removal; otherwise mold returns. Document the dry standard and daily progress.
- Build critical barriers from 6-mil poly and maintain negative pressure. Size HEPA air scrubbers for 4–6 air changes per hour (ACH) in the containment volume.
- PPE: half-face respirator with P100 cartridges, sealed goggles, nitrile gloves, disposable suit. An N95 is not the default for remediation work.
- Remove porous materials (drywall, insulation, carpet) that cannot be cleaned; bag in poly before carrying through clean areas.
- HEPA vacuum and damp-wipe remaining surfaces. Apply an EPA-registered antimicrobial only after cleaning; it does not replace source removal.
- PRV: visual inspection plus air sampling (spore trap or culturable). Clearance requires the area to be dry and clean.
Worked example
A 3 m × 4 m room with a 2.4 m ceiling has a containment volume of 28.8 m³. At 4–6 ACH, required airflow is 115–173 m³/h. A scrubber rated 200 m³/h is adequate; verify with a manometer or smoke test that the barrier holds negative pressure. Remove drywall at least 1 m beyond visible growth and bag it. Do not sample until drying is complete.
Traps
Treating Condition 2 as Condition 3; skipping moisture correction; using fogging as a substitute for removal; sampling before drying; and extending containment too little.