4 Tips for Proper Mold Remediation and 10 Tips for Containments

Use ANSI Standards as a Guide

While there is little regulation of the mold remediation industry in the U.S., keep in mind that there are standards that are based on solid science and are recommended, but they are not required. Many mold professionals say they use these standards, however, it’s important to know these procedural standards before hiring a mold remediation contractor. Here’s more on that standard, including new changes that are worthwhile to know.


ANSI/IICRC S520 Standard and IICRC – R520 

Reference Guide for Professional Mold Remediation should be the procedural standard for the remediation of mold damaged structures and contents.

NOTE: All water penetration causes should be discovered and corrected properly, prior to restoration work, to ensure no further damage.

4 Tips for Proper Mold Remediation

  1. WRITTEN DISCLOSURE: Remediation professionals must disclose, in writing, that they are deviating from the standard. This includes if they do both testing and remediation, as that is considered a conflict of interest. (What is their incentive to tell you that they did a bad job and the mold isn’t actually gone or worse?)
  2. NO COATINGS IN LIEU OF MOLD REMOVAL: All testing must be done before any coatings are applied. Coatings do NOT provide a barrier to mold spores or their very toxic by-product, called ‘mycotoxins’.
  3. NO FOGGING IN LIEU OF MOLD REMOVAL: Also, remediators should NOT mist or fog in an attempt to kill mold, in lieu of source removal.
  4. CONFLICT OF INTEREST DISCLOSURE IN WRITING: Remediation and testing done by the same company presents a ‘complexity,’ which is required to be disclosed in writing per the ANSI/IICRC S520 Standard. This is mentioned in the ANSI/IICRC webinar, as a ‘conflict of interest’. The person or company that does the testing should not be the same as the one who does the work, without proper disclosure. An unbiased confirmation of air quality status and successful remediation is always preferred and required by the ANSI, unless otherwise disclosed in writing.

10 Tips for Proper Containment

The EPA recommends full containment is recommended for the cleanup of mold contaminated surface areas greater than 100 square feet or in any situation in which occupants have reported health symptoms and it appears likely that the occupant space would be further contaminated without full containment.

  1. Double layers of polyethylene should be used to create a barrier between the moldy area and other parts of the building. Install appropriate and full complete containment around the work areas, typically using 6-mil polyethylene sheeting to separate the mold abatement work area from other uncontaminated or occupied areas of the building, with access to a window or door included in the containment for exhausting air scrubbers. A double barrier is recommended, in which the contaminated inner layer can be removed after cleaning but before clearance approvals. 
  2. A decontamination chamber or airlock should be constructed for entry into and exit from the remediation area. An air-lock type vestibule is recommended for workers to remove contaminated protective gear and double bagged debris for proper disposal. 
  3. The entryways to the airlock from the outside and from the airlock to the main containment area should consist of a slit entry with covering flaps on the outside surface of each slit entry. 
  4. The chamber should be large enough to hold a waste container and allow a person to put on and remove PPE. 
  5. All contaminated PPE, except respirators, should be placed in a sealed bag while in this chamber. 
  6. Containments should be placed under negative pressure relative to the rest of the building using air filtration devices such as an air scrubber equipped with high-efficiency particulate air (HEPA) filters. The air should be discharged outside the containment to the outdoor atmosphere. Clean HEPA Air scrubbers should be used during all remediation work and for 48-72 hours after the work is complete. 
  7. Air handling systems must be isolated from the work area. This is the duct and furnace system. Protect all supply and return ductwork from the remediation and follow-up construction debris. 
  8. Protect uncontaminated spaces during removal of debris as agreed to by the owner. 
  9. Remove mold-contaminated gypsum wallboard in large pieces to minimize aerosolizing mold spores. 
  10. All debris to be sealed in doubled 6-mil polyethylene bags or wrapped in sealed polyethylene sheeting, while in the containment. Bag before removal from contaminated areas and removed the most efficient way possible. No material should be recycled. 

Ask to see your remediation company’s copy of the full ANSI Standard. Many claim to follow ANSI Standards but don’t seem to know much about them.

For more information, see these organizations and publications


  • American Board of Industrial Hygiene (ABIH) 
  • American Conference of Governmental Industrial Hygienists (ACGIH) 
  • American Council for Accredited Certification (ACAC) 
  • American Industrial Hygiene Association (AIHA) 
  • Environmental Protection Agency (EPA) 
  • National Air Duct Cleaners Association (NADCA) 
  • National Institutes for Occupational Health and Safety (NIOSH) 


  • ACR, The NADCA Standard for Assessment, Cleaning & Restoration of HVAC Systems 
  • Bioaerosols: Assessment and Control, edited by Janet Macher, SC.D., M.P.H., ACGIH. 
  • Guidelines on Assessment and Remediation of Fungi in Indoor Environments , NYC Department of Health and Mental Hygiene 
  • Field Guide for the Determination of Biological Contaminants in Environmental Samples, Second Edition, AIHA. 
  • IICRC S520 Mold Remediation, ANSI/IICRC S520 Standard and IICRC R520 Reference Guide for Professional Mold Remediation, Institute for Inspection, Cleaning, and Restoration 
  • Mold Remediation in Schools and Commercial Buildings, Environmental Protection Agency

Get your questions answered!

Cheryl Ciecko, AIA, ALA, LEED AP, is a licensed architect who helps homeowners and building professionals create safe homes through online education to prevent mold, water damage, and poor indoor air quality. You can find her video masterclasses, online programs, and education subscription options at https://avoidingmold.com/education .

For detailed answers on your specific situation or building project, schedule your appointment for an individual consultation.


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The information contained in this presentation is for educational purposes only and is not intended to diagnose, prescribe, treat, or cure any disease, ailment or injury to the body. It is not medical advice. FDA regulations prohibit the use of medical claims in conjunction with the sale of any product not approved by the FDA. Statements made herein have not been evaluated by the FDA. 

Any products, techniques, and/or personal usage tips referred to are not suggested as a replacement for proper treatment from a licensed health care professional. I am not a licensed health care professional and the decision to use or not to use any of this information is the sole responsibility of the listener and/or reader. Everyone is an individual with different body types, different blood types, different body chemistries, and it is important to remember that what works for one person may not work for another person.