Photograph of mold contamination in a building (C) InspectAPediaMold Action Guide
What to do about mold, mildew, and other indoor allergens found in buildings

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Action Plan for Indoor Mold Contamination:

Here we describe in step by step detail just how to deal with building mold: find, test, remove, prevent indoor toxic or allergenic or even just cosmetic mold contamination & growth in buildings

This toxic mold article series provides an easy to understand step-by-step guide for dealing with toxic or allergenic indoor mold and other indoor contaminants: what to do about mold contamination in buildings: how to test-for mold, find hidden mold, clean up or remove mold, and prevent mold.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Action Guide for Dealing With Mold Contamination In or On Buildings

Photo of mold on (C) Daniel Friedman The steps in this document and its accompanying articles will be sufficient for many building owners who want to do their own mold investigation, mold testing, mold cleanup, and mold prevention in their home or office. The photo shows a small moldy area in a residential bathroom.

Mold "mildew," moisture, in your house or office, building-related illness, involves your physician, medical treatment, sick building investigators, possibly professional cleaning companies, steps to reduce the future creation of mold or other indoor irritants, and possibly the special products to help clean buildings and air.

In this Mold Action Guide that continues below, for each step in the process of diagnosing, identifying, removing, and preventing indoor mold problems in buildings, links to in-depth articles are provided. In some cases in this document I use excerpts from longer dissertations on these subjects.

Article Contents

We offer links to more detailed mold contamination detection, cleanup, prevention & health concern documents throughout this article and at the article bottom.

You can scroll down through this document in sequence, or use the links at the page toparticle outline to jump to specific subtopics of dealing with building mold concerns.

Useful articles on building mold contamination troubleshootingPhoto of mold on (C) Daniel Friedman

SEE A DOCTOR? Should you consult with physicians and knowledgeable indoor environment experts

Stachybotrys spores (left) and structure (right)A simple clue that suggests that one may be suffering from building related illness is the abatement of symptoms when the person with the complaint spends time out of the building. However the converse - when symptoms do not abate - does not rule out a building as a contributor to the complaints.

Some mold-related illness symptoms are slow to diminish, and more than one building can contribute to complaints.

Proving with scientific accuracy that a substance in a building has actually caused or aggravated a specific illness is a difficult and costly procedure.

A common approach taken by building diagnosticians who are considering whether or not mold in a building is (or could be) making someone sick is simply to look for substances which are believed likely to cause or aggravate illnesses and complaints. If such materials are present at significant levels they should be removed.

Some people should stay away from mold cleanup operations

If you are sick, asthmatic, immune-impaired, suffer from COPD or other respiratory illness, before attempting any mold cleanup yourself you should see your family doctor, allergist, pulmonologist, medical toxicologist, or other appropriate specialist to discuss the chances that the environment might cause or contribute to or aggravate your illness.

If you suspect that your illness is caused by or aggravated by conditions in your building you should discuss that with your physician.

Photo of mold on (C) Daniel FriedmanAnd if you are yourself or if people with these characteristics are present: elderly, immune impaired, infant, asthmatic, suffer from COPD or other respiratory or immune disorders or any illness that could be aggravated by exposure to respiratory irritants, VOC's, allergens, mycotoxins, etc., you should be wary of allowing any handling moldy or dusty materials without first checking with your doctor.

Medical relocation of certain high-risk building occupants may be needed before moldy materials are disturbed.

More Reading for Mold Related Illnesses

DO IT YOURSELF: How to Perform Your Own Mold Inspection, and Check for Mold-Causing Conditions

Photograph of a small mold cleanup job.Small area mold cleanup: We emphasize that for small areas of mold contamination, generally where less than 30 square feet of contiguous mold is present, simple building cleaning and renovation procedures are all that's needed and testing is usually not appropriate. Most building mold contamination falls in this first category.

At DO IT YOURSELF MOLD CLEANUP we provide suggestions for a do-it-yourself cleanup of small areas of mold.

At MOLD / ENVIRONMENTAL EXPERT, HIRE ? we provide guidelines to help decide when it is probably justified to bring in a mold expert to perform mold inspection and testing in a building.

Reduce your exposure to mold: Examine living/working conditions for opportunities to reduce exposure to mold or other allergens. This means don't move your sick mother into a damp moldy basement while you're painting her bedroom.

More generally it means you don't need to prove that a specific mold in a building is making you sick to recognize that a problem mold is present and needs to be cleaned-up.

But if you are sick, finding out what you've been exposed to might be helpful to your doctor. I've had clients with severe mold-related illness which went unrecognized and mistreated. If you're ill, ask your doctor if there is any reason to suspect an environmental factor or if there is reason to be extra careful to avoid exposure to mold or indoor allergens

Find the Mold: Examine living/working conditions to find evidence of any mold or to determine the actual extent of mold problem in the building. In the photograph above, leaks behind and under a bath vanity had produced mold that should be removed (and when rebuilding, steps should be taken to prevent future mold growth). But this small job, less than 10 sq .ft. of moldy material, is well within the abilities of a handyman, plumber, or skilled homeowner who can follow appropriate procedures.

Clean-up Mold: remove or clean up problem mold reservoirs. But don't be fooled into spending an outlandish sum on removing a "cosmetic" mold. Later below you'll read about stuff that is not mold or is only a cosmetic mold.

Find The Causes of Mold: In addition to looking for reservoirs of existing mold, examine the building for evidence of leaks (current or old) or moisture problems as those often define the most-likely mold reservoirs. If there is mold in your attic, has there been a history of basement flooding? Even if you don't see mold on exposed building surfaces, finding mold-producing conditions or events, like traces of leaks into a wall or ceiling, can tell you where a mold problem may be hidden.

The steps in this document - THE MOLD ACTION GUIDE - will be sufficient for many building owners who want to do their own mold investigation, mold testing, mold cleanup, and mold prevention in their home or office. However do-it-yourselfers should pay close attention to what can go wrong. If you haven't already read HIRE A PROFESSIONAL? you should do so now. I encourage healthy, not-at-risk people to handle small mold problems themselves. You don't need to hire an expert to clean up moldy bath tiles or a square foot of moldy drywall. But if you are proceeding on your own, be alert for the discovery that the extent of the problem is large enough that you should stop and bring in a professional.

With these warnings made clear, continue by reviewing the next steps below - by scrolling down or by using the links at the left on any of our web pages.

If you're unsure whether to tackle mold yourself and want to know when to bring in a professional, see HIRE A PROFESSIONAL?

Mold HEALTH RISKS for Building and Home Inspectors

Photograph of a health department sign placed on a moldy apartment that was unsafe to enter.


HOW TO FIND MOLD: How to Inspect Homes and Other buildings for Mold - the Basics of How to Find Problem Mold Indoors

Photograph of mold found behind paneling in a bathroom.

Please see HOW TO FIND MOLD and WHAT MOLD LOOKS LIKE for full details.

Any experienced home inspector can identify conditions that risk water entry or high moisture levels in a house. These conditions promote the growth of mold spores. Mold is a natural organism and it's virtually everywhere. The goal of "zero" mold spores makes no sense.

A home inspection is not a reliable indicator of the presence or absence of problem mold unless there is a large non-cosmetic mold reservoir actually visible. In fact often mold samples collected by a non-expert fail to identify the more important mold reservoirs in a building.

But the visual inspection of the building by an experienced inspector is a great place to start. if building conditions such as a history of wet conditions have been present, these promote mold growth so mold problems are more likely.

For detecting evidence of a mold problem in a building you should review these articles.

HOW TO CLEAN UP MOLD: How to Clean or Remove Mold, Moldy Debris, Other Indoor Environmental Contaminants

Photograph of moldy basement ceiling before cleaning. Photograph of a basement ceiling after cleaning by media blasting.

For small areas of mold contamination, generally where less than 30 square feet of contiguous mold is present, simple building cleaning and renovation procedures are all that's needed and testing is usually not appropriate. Most building mold contamination falls in this first category.

At DO IT YOURSELF MOLD CLEANUP we provide suggestions for a do-it-yourself cleanup of small areas of mold.

At MOLD / ENVIRONMENTAL EXPERT, HIRE ? we provide guidelines to help decide when it is probably justified to bring in a mold expert to perform mold inspection and testing in a building.

Please see these articles for full details on removing mold and assuring that the mold cleanup was handled correctly:

  5. MOLD LEVELS IN buildings

Protect the occupants and yourself from mold, demolition dust, debris, cleaning chemicals, etc. Where a large area of cleanup is involved (more than 30 sq .ft.) a professional is usually called to establish negative air in the work area and to install containment barriers of plastic or other material to protect cleaner areas of the building from cross-contamination during the cleanup.

If you used a building environmental specialist to inspect and define the scope of work, you should have baseline mold test samples of both the work area and other building areas which will permit you to state definitively, at the end of the cleanup, whether or not the cleanup has caused cross-contamination of other building areas.

The spotless cleaning produced for the second photo above was obtained by using a professional who used media blasting to clean these surfaces. Such measures may be needed for large or complex surfaces, but quite often the necessary steps are less technical and less onerous, as we describe next.

Clean or remove mold and moldy debris: The most succinct Mold Remediation or Mold Cleanup Guidelines one could state would be this: the objective is not to sterilize your environment or "kill" mold, steps which are ineffective anyway - the operative words are "clean" or "remove" problem mold and then to correct its cause. We're talking about scrubbing here. It's the physical removal of moldy or allergenic debris that's important, not the surface sterilization.

The second I permit someone to "spray for mold" I can count on them to fail to do an adequate cleanup. Moldy drywall, paneling, trim, carpets, boxes, junk, are removed and disposed-of as construction debris or trash.

Be sure to remove insulation that has been wet or smells moldy or has been exposed to high levels of airborne mold. Clean all of the exposed surfaces. You could use water, soapy water, spray cleaners, or if you must, a dilute bleach cleaning solution. But bleaching is not the object. Keep that in mind.

More Reading: Mold Cleaning Procedures & Mold Remediation Standards Guidelines

BUILDING FLOODS: What to do to Prevent Mold Growth After a Building Flood or Burst Pipe

If you scrolled down instead of using the links at left, you can read the most-current version of this article at BUILDING FLOODS - or use this FLOODS & MOLD CLEAN/PREVENT link

If your building has just been flooded by rising flood waters, a burst pipe, a waste line leak or other event, immediate action may prevent a very costly mold cleanup.

Review this checklist. If your building already has an actual or suspected mold problem, review this "Mold Action Guide" web page (this document).

If you did not take the steps in "Building Floods" below and are reading this section days or weeks after the flooding event, a comprehensive building survey for hidden mold or other contaminants may be needed before a full building cleanup plan can be made.

For full details of what to do to clean up a building after flooding to remove mold or to prevent mold growth in a flooded building see Building Floods - Steps to Clean and Prevent Mold.

More Reading: For more depth of understanding of mold prevention and cleanup see these articles:

CLEARANCE INSPECTIONS: When & How to Perform a Mold Remediation Clearance Inspection

Details about mold clearance inspections are now at CLEARANCE PROCEDURES. This header and link remains in the main document for people who scroll down instead of using the links at left.

To read about post mold remediation clearance inspections please use this link.

HOW TO PREVENT MOLD: Correct the Causes of Mold and Prevent Indoor Mold or other indoor environment problems

Photograph of a contractor pointing out wall leaks at an air conditioner..

For details on preventing mold contamination in buildings see MOLD PREVENTION GUIDE for the full article on this topic.

Our photo (left) shows a contractor pointing to wall leaks at an air conditioner, a source of mold found indoors at this building.

There is no point in "cleaning up" or "removing" mold if the underlying causes of a mold problem are not also addressed. Unless the causes, such as leaks or high moisture are corrected, mold will simply recur.

Band-Aid approaches like trying to "kill" or "prevent" mold by using chemical sprays, coatings, or air cleaners are insufficient and ineffective at preventing future mold and in some cases (such as OZONE MOLD / ODOR TREATMENT WARNINGS) these approaches create their own hazards.

In the photo at above left, the contractor is pointing out to the owner that wind-blown rain running down the building's wall will enter the wall cavity at the air conditioner penetration because of improper installation and sealing there. Inside we found that the wall cavity was wet and moldy.

Proper installation and sealing at building wall and roof penetrations such as roof vents, windows, doors, and trim can prevent many building leaks which in turn reduces the chances of a future mold problem.

Photograph of severe ice dam leaks on an older home. Attic Condensation and Ice Dam Leaks: If roof leaks or attic moisture condensation due to a combination of inadequate attic ventilation and a building moisture source (wet basement, plumbing leaks, roof leaks) causes excessive moisture or actual wet conditions in an attic, conditions are ripe for extensive mold growth.

Photograph of leaky wood shingles on a home exterior.

Building Exterior Leaks and Mold No mold cleanup project will be successful unless you correct the conditions that caused mold growth in the first place.

The photograph shows a double problem with this wood shingle exterior wall: shingles are improperly installed and falling off of the home, inviting water to enter the wall structure. Because there is no roof overhang or eaves, and not even a gutter on the home, roof runoff runs right down this wall.

Photograph of plumbing leaks into a basement ceiling.

Building Interior Leaks and Mold:
address interior conditions that produce or serve as reservoir or amplifier for common allergens: mold, pollen, pet dander as well as other possible respiratory irritants such as latex, paints, product-outgassing furniture or carpets, and renovation hazards such as lead paint or chemicals or other environmental issues.

The photograph shows extensive staining from protracted plumbing leaks in a house that was left unattended. The result was extensive basement mold requiring demolition and cleaning of large area of the home.


Photograph of leaks into HVAC duct work (C)DJ Friedman.Indoor Humidity Control:
What indoor humidity should we maintain in order to avoid a mold problem? A maximum indoor relative humidity of 55 should be OK, 50 better, 45 for an attic knee wall space which is not vented to outdoors. The moisture level you detect varies depending on when, where, and how you measure it.

Photograph of leaks into HVAC duct work (C)DJ Friedman.

Our experience is that fiberglass and fiberglass-lined ducts and air handlers cannot be cleaned effectively and worse, improper cleaning may cause dangerous release of fiberglass into the building air.

Don't just spray ducts with disinfectants and sanitizers.
However it is also our experience that it's rare (not impossible, just rare) for the duct system itself to be the source of the main mold problem in a building.

Photograph of a portable air cleaner.

OPINION: our clients' experience, confirmed by our own field testing suggest that in a room without severe dust and particle reservoirs (no pets, no wall to wall carpets), some air cleaners might reduce, but by no means eliminate, problematic airborne particles. The particle reservoir forms what is in a practical sense, an infinite particle source.

My House Makes Me Sick: A Quick Action Plan for Moldy House Complaints

Reader Question: Health Crisis in My Home: Mold is Making Me Sick but I Don't See Where the Mold Is

I am sick with violent headaches and nausea that occurs when I am home more frequently than when I am out. My wife is unaffected, at least not to the extent I am. I have mold/s in my house. It smells like mildew; I can not see it on walls or surfaces inside, but I can smell it in clothes, drawers, closets, and even in open air at time, especially after a rain.

There is plenty of green mold on the outside of our home (even though I pressure-wash at least once every 3 months), and there is also a nasty grayish sediment on the outside roof overhangs (bug excrement or carcasses from spiders and scorpions eating. (yes, I have scorpions). I live in the swamps of south Georgia with high humidity and acidic soil and water. (great environment for all kinds of molds I know)

Solutions I have already tried to no avail: one dehumidifier running in master bedroom, HEPA air purifiers (large floor model from home depot) running in 3 rooms, fungus control treatment of our lawn, and mold inhibitor spray on the vinyl siding. HEPA air filters now smell like mildew when turned on even when I change the filters.

If mold is in the concrete slab (housing foundation) and the carpets (which I am removing) like I think it is, what can I do short of move and or spend 10s of thousands of dollars?

Sick and tired of fungus in Georgia - J.E. 10/28/2013

Reply: A summary of steps to address your indoor mold complaint

A competent onsite inspection by an expert usually finds additional clues that would permit a more accurate, complete, and authoritative answer than we can give by email alone. You will find additional depth and detail in articles at our website.

That said I offer these comments: 

Starting at ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD I list in more detail some suggestions that you will want to review.

But below and in response to your question I offer a more brief summary of recommendations based on your specific inquiry: If you feel that conditions are an emergency, see MOLD EMERGENCY RESPONSE

You should start with your own doctor and a thorough discussion of your health concerns; include among your questions for the physician whether or not the indoor environment is likely to be significant in your case (as you certainly sound and suggest) MOLD DOCTORS - ENVIRONMENTAL MEDICINE may help but it's best to start with a referral from your own doc. 

Our article MOLD / ENVIRONMENTAL EXPERT, HIRE ? helps decide when to hire a professional - which your email also suggests is probably appropriate. A true professional won't just stop by to take an air test (which would be nonsense, though profitable). Instead she will inspect the entire structure inside and out to identify risk points that deserve further or perhaps even invasive inspection to look for a hidden problem.

Regarding indoor mold contamination and air quality steps you have already taken, 

An indoor air cleaner can reduce airborne particle level when it operates in a small-enough area to match its capacity.  But running a portable "air purifier" will never ever actually correct an indoor mold, other particle, nor gas contamination problem any more than waving your vacuum cleaner in the air in the kitchen will suck up dust bunnies from under the living room couch. You need to find and fix the problem source.

While running a dehumidifier can reduce indoor humidity level and thus reduce the friendliness of the indoor environment to grow mold as well as some other indoor contaminants, a humidifier will never correct an indoor contamination source - to do that one needs to find and remove the problem and then to understand and fix its cause so that the problem does not recur.

If a mold reservoir is indeed in your indoor carpets, you are correct to remove them. Wall-to-wall carpets in moldy shape are discarded along with carpet padding. Area rugs that are worth the cost can usually be professionally cleaned.

Mold won't be "in the concrete" though porous materials might absorb MVOCs and thus be smelly. Following carpet removal the floors should be cleaned. Perhaps you'll consider installing a different sort of floor covering (stained polished and sealed concrete, ceramic tile, even vinyl floor tile or sheet flooring can be easily cleaned, reduce the indoor airborne particle level, and don't form a friendly mold reservoir.

Prevent future indoor mold contamination & mold growth

If you find that more extensive demolition is needed and you want to re-build or restore the building to be as mold resistant as possible, see MOLD PREVENTION GUIDE

Regarding outdoor mold contamination

Regarding pressure washing: it is not normal to need to pressure-wash a building exterior every 90 days, and may even be unconscionable on the part of your contractor. Something is wrong there. And worse, an inept pressure washer might make your indoor environmental mold problems exponentially worse by spraying exterior siding improperly so that water enters the building wall cavities. Be sure to discuss this worry with your on-site expert. 

Spraying a "mold inhibitor" on exterior siding is, if you'll pardon a mixed metaphor, barking up the wrong tree (or wall). First, it is normal for there to be mold everywhere outdoors. Second, if your siding is moldy (or more likely is growing algae) it's due to other factors: shade, for example, or rain splash-up on walls, or an idiot spraying water into the wall cavities.

Cleaning the exterior walls properly once, and if walls are paintable, using a paint that includes a fungus inhibitor (also a toxic chemical), and taking steps to increase sunlight on and air flow around exterior walls are the sorts of corrective steps that might reduce that problem. But outdoor mold is not the cause of an indoor mold air quality problem, as I've discussed above.

South Georgia is indeed a very humid climate. If your building uses air conditioning, that system too needs to be inspected for proper operation and for cleanliness. Properly working, central air or even window air conditioners ought to be dropping the indoor relative humidity, making use of a dehumidifier unnecessary.

Mold Action & Cleanup Guide Articles


Continue reading at MOLD CLEANUP GUIDE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see EMERGENCY RESPONSE, IAQ, GAS, MOLD - separate article

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ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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