When Cleaning Is Not Enough โ When You Need Remediation
Surface mold (a few black spots on bathroom tile grout, a small spot on a window sill) is a CLEANING job โ wipe with appropriate cleaner, address the moisture source. Remediation is the trade-level work needed when mold has colonized building materials (drywall, framing, subfloor, insulation) and remediation requires removing the affected materials, not just cleaning surfaces.
The line is roughly 10 square feet of contiguous growth. Below that, surface cleaning often suffices. Above that, you need IICRC S520-compliant remediation: containment, source removal, HEPA filtration, antimicrobial treatment.
Most of the "mold removal" services advertised at $500-$1,500 are surface cleaning, not remediation. Real remediation for a 50-100 sq ft affected area runs $3,500-$8,000 typically. The difference matters for insurance reporting and for whether the mold actually stays gone.