Remediating Mold


Dr. Adrienne Sprouse

Dr. Adrienne Sprouse


I am pleased to have A. Anthony Hibbert, Certified Mold Inspector and Mold Remediator, as my Guest Blogger for June.   Anthony has evaluated and remediated countless homes and other buildings for water contamination, mold, and other issues of poor indoor air quality.     

Remediating Indoor Mold

“You’ve got mold,” your inspector tells you.  You are not surprised—you had suspected it all along—the musty odor, the upper respiratory-asthma-like symptoms, headaches, and fatigue.    He tells you that there is evidence of an old leak from your air handler in the attic.  You remember that a year ago the condensate tube had cracked and sent water running all over the living room ceiling, the bathroom, and down through the floor into the basement.  That’s when you realize that the contractors you hired had not thoroughly dried out the wet areas—and now you’ve got mold.

Here’s another scenario:  You recently moved into a new, dry and clean apartment thinking you were safe.  Your previous apartment was moldy and the landlord refused to fix the problem appropriately so you moved.    For some reason, even in your new place, you’re still not feeling well.    After some testing and research, you realize that you unwittingly brought the mold into your new dwelling when you brought in the furniture and other items from your previous apartment.   So what do you do now?

These scenarios are repeated over and over again in homes and offices across the country.  A big part of the reason is that mold is often taken lightly, treated more as a nuisance than a risk to your health.   “Its just mold,” someone says.  “Get some bleach and clean it up, then paint over it!”

All contractors may not approach the remediation of mold in your home the exact same way, but there are specific protocols that should be followed.   What are these protocols?

Choose the Right Contractor

Even a good standard building contractor may not be suited for your water damage or mold remediation job.   Why?  Because this otherwise great contractor, may not have specific training in drying and mold removal.   So, the first quality you should look for in your potential remediation contractor is that he has specific knowledge and experience in water and mold damage mitigation.   Ideally, he should be certified with one of the numerous reputable associations or institutes such as the Institute of Inspection, Cleaning and Restoration Certification (IICRC), Indoor Air Quality Association (IAQA), American Industrial Hygienist Association (AIHA), and Environmental Solutions Associations (ESA).

You Need the Right Equipment

The contractor you hire should have a number of specialized tools.  There are many, but the following is a summary of the most important ones:

Moisture Meter allows the contractor to detect moist or damp areas and insure that when he has completed the remediation, all building materials are dry.   Reconstruction, or replacing new materials, must not begin until all areas are dry.

Negative Air Pressure Machines (also known as air scrubbers).  These machines come in various sizes fitted for the size of the job.   They are rated by how much air they move in cfm’s (cubit feet per minute).   This system includes pre-filters (normally at least two) and a true Hepa filter which traps very fine, microscopic particulates, like mold spores.    Negative air pressure means that a duct is attached to the unit and connected to the outside of your building, usually through a window.  This allows the unit to trap mold spores and other fine particulates while the remainder of the air is discharged outside.   This vacuum helps to protect the workers and occupants while the remediation is in progress.

Hepa Vacuums are specialized vacuums with a true Hepa filtration system.   A good one has four or five stages including pre-filtration as well as the Hepa filter.   Hepa vacuums are mandatory for the remediation contractor.

Cleaning Utensils or Machines.   These tools include a variety of brushes from heavy duty wire brushes and power wire brushes, to media blasters, emitting baking soda, dry ice, etc.  These tools or machines are used to clean structural surfaces and help remove mold growth.   Media blasting machines are similar to sand blasters, but instead they blow specially designed media like baking soda, dry ice, husks, or sponges.

Dehumidifier(s) are needed to keep the relative humidity (ambient air moisture) between 30- 50 Rh during remediation, and sometimes after remediation.

Fix it!   

Before effective remediation can begin, the cause of the water intrusion or damage must be repaired or corrected.   Cracks or breaches in the foundation walls, leaks in the roof, leaky windows, plumbing leaks or drips, or heavy condensation from unwrapped piping.   Any source of excess moisture or dampness needs to be corrected.


The next critical step in effective mold remediation is the removal of all non-salvageable wet or contaminated building materials—and all means all.   All materials must be removed, even those inside tight spaces and crevices.  This includes damaged wallboards, paneling, decorative wood boards, wallpaper, and fiberboards.  Insulation in ceilings, walls or floors, must also be removed.   Non-salvageable carpeting, floor boards, vinyl flooring, hardwood flooring, sub-flooring, etc., must be removed too and preferably double-bagged and then discarded.   No contaminated materials must remain.   Any remaining mold can grow back inside the ceiling, wall, or floor cavities after reconstruction.    Often padded furniture such as couches, love seats padded chairs, box springs, mattresses, etc. must also be discarded.  Books and other paper items often transport mold spores and mold toxins and may need to be discarded as well.  Remember, it is critical, that all work be done with negative air pressure.                                      


Heavy duty plastic sheeting, usually at least 6 millimeters thick, must be installed over entries or openings in walls or ceilings, separating work areas from non-affected areas prior to beginning work.  Remember, no one should be inside the containment area except those performing the remediation, and the flaps should be kept taut at all times.

Clean, Clean, and Clean Again

After removal of contaminated materials, the next stage is cleaning exposed framing and surfaces.   First there is the rough or initial cleaning.  Second, the detailed surface cleaning and sanitizing.   Rough or initial cleaning may involve media blasting, such as baking soda or dry ice blasting which removes viable mold.   With smaller jobs, wire brushing or power brushing and light sanding may be used instead of media blasting.

After the initial removal of heavy visible mold, all of exposed remaining surfaces must be thoroughly wet-wiped, sanitized, and Hepa-vacuumed.  That is everything must be meticulously wet-wiped (not dry-wiped) and Hepa-vacuumed:  furniture, contents such as books, knick knacks, walls, ceilings, windows and floors; utilities, plumbing pipes—everything!  And they must be cleaned (wet wiped) to as near dust-free as possible.  That’s right!   Practically dust free!    Remember, cloths have to be wet or damp with a cleaning agent or biocide-a product that can kill mold.

Chemicals and More

There is a plethora of chemical agents that can be used.   Many of these products, while quite effective, can be mild to very caustic and require extensive ventilation (supplied air).   Bleach is not recommended.   There are a number of non-caustic and non-allergenic products on the market, such as commercial grade hydrogen peroxide, vinegar, and enzyme-based cleaners which are effective and safer for occupants and technicians releasing little or no VOCs (volatile organic compounds).

After treating surfaces with a biocide, a good soap or cleaner is needed to remove heavy debris and staining.   This can range from a household soap to a commercial low-VOC degreaser.


Encapsulation is the sealing of cleaned or treated surfaces with a kind of paint—a primer of sorts, often with antimicrobial properties which help to protect the substrate such as porous material like wood, from subsequent fungal growth.   Encapsulation may not be needed after media blasting since it thoroughly cleans the wood and removes the roots (fungus mycelia).  But encapsulation is most definitely needed if the surfaces were cleaned by hand or by other chemicals, since these methods are not as thorough as cleaning with a blasting media.                                                                                     


A final wipe should include an ammonia solution (3% to 20% ammonia) to neutralize the mold trichothecenes.  Although no one agent can neutralize all mold toxins, ammonia has been proven to be the most effective single agent against the mycotoxins produced by mold.  Trichothecenes are very toxic (poisonous to humans and other animals) and difficult to destroy.   So, spraying, fogging, or wet-wiping with ammonia in the middle or final cleaning stages is important to abate this very harmful chemical.   Ammonia is also an effective biocide (mold killer), however, some contractors prefer to use it only at the final stages of the cleaning process because of its pungent nature)


Ozone (O3) is a natural occurring gas.  However, there are generators that can produce ozone.  Ozone is great for destroying bacteria, viruses, VOCs, MVOCs,  odors, and molds.  In short, it purifies the air.  It is a very good idea to ozone at the very end of the remediation process.  Ozonation should be performed by a contractor experienced in ozone generation to assure no one is in the home when the ozone is applied, and that ozone levels have returned to a safe level before anyone re-enters the home.

Post-Remediation Testing and Assessment

Post-remediation air and surface sampling, along with a visual inspection, are highly recommended to insure the remediation was successful.   Measurement for high humidity, mold spores, and residual mold toxins should be made.  This post clean up assessment is usually performed by a hygienist or mold inspector—preferably by a different person than the one performing the remediation.

 In Conclusion                                        

To insure that your mold contamination is remediated appropriately, do not take it lightly.   Follow the professional protocols, and you could prevent years of suffering and spending thousands of dollars on ineffective remediations.  

A. Anthony Hibbert

A. Anthony Hibbert

 A. Anthony Hibbert is a New State Licensed Home Inspector, New State Certified Radon Specialist, and a certified mold inspector and mold remediator.  He owns  Perfect House Home Consultants, LLC, and is the Project Manager and Technical Supervisor for Rainbow International of South Rockland.   Tel (845) 807-1933


EPA Remediation In Schools and Commercial Buildings

New York City Department of Health: Guidelines on Assessment and Remediation of Fungi in Indoor Environments.

IICRC S 500 and S 520

3 Responses to “Remediating Mold”
  1. Peter says:

    These are very helpful and germane topics with all the post storm residuals. I sent this to my staff and family.

  2. Thanks you for this helpful guide! At least now I know the right questions to ask and what procedures are to be carried out when hiring a mold remediation company.

  3. House Mold says:

    Very nice post. Scenario two actually happened to me. I moved from my apartment building which had mold to a new lease. I thought we had removed mold from every surface. I was wrong. I had actually brought all my mold with me, be it through my furniture or my clothes. If only this post came sooner I could have preventing having to hire another water damage restoration company

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