This article is provided by the International Association of Certified Home Inspectors
Preventing And Stopping Mold Damage
Dry items before mold grows, if possible. Mold can grow instantly if there is adequate temperature, moisture and nutrients provided.
Dry carpet and backing within 48 hours, remove water with a wet vacuum, pull the carpet and pad off the floor, and dry them using a fan to blow air over them. A dehumidifier can be used to reduce the humidity in the room where the carpet and backing are drying, while fans can be used to accelerate the drying process.
Water can be removed from concrete or cinder block surfaces with a water-extraction vacuum. Dehumidifiers, fans and heaters can also be used to accelerate the drying process. Hard surface flooring (such as linoleum, vinyl and ceramic tile) should be vacuumed or damp-wiped with a mild detergent, and allowed to air-dry. They should be scrubbed clean, if necessary. If the under-flooring is wet, it should be dried using a vacuum or by exposing it to the air.
Non-porous, hard surfaces, such as plastics and metals, should be vacuumed or damp-wiped with water and a mild detergent, and then allowed to air-dry. Scrubbing may be necessary to thoroughly clean the surfaces. Water should be removed from upholstered furniture with a water-extraction vacuum. Fans, dehumidifiers and heaters may be used to accelerate the drying process. Completely drying upholstered furniture within 48 hours may be difficult, so if the piece is valuable, consider consulting a restoration or water-damage professional who specializes in furniture.
Drywall, also known as gypsum board or gypsum wallboard, may be dried in place if there is no obvious swelling and the seams are intact. Otherwise, removal is necessary. The wall cavity is the most difficult area to dry, and it should be ventilated if the drywall is left to dry in place.
(Drywall is not made out of boards of wood; traditionally, drywall is made of the mineral gypsum with a layer of heavy paper on the outside and inside. Commercial gypsum boards and drywall are also available with a variety of outside layers and coatings. According to the U.S. Geological Survey, a typical new home contains more than 7 metric tons of gypsum.)
To clean water-damaged window drapes, follow the manufacturer's laundering or cleaning instructions.
To clean wooden surfaces, remove moisture immediately and use dehumidifiers, fans and gentle heat to dry them. (Be very careful when applying heat to hardwood floors.) Treated or finished wood surfaces can be cleaned with mild detergent and clean water, then allowed to air-dry. Wet paneling should be pried from the wall for drying.
Some water-damaged items, including ceiling tiles, cellulose and fiberglass insulation, drywall and gypsum board, and books and papers, may have to be discarded. If valuable or important books, documents or other items are moldy or water-damaged, consult a restoration, water-damage or remediation expert.
These guidelines are for addressing damage caused by clean water. If you know or suspect that the water is contaminated with sewage or with chemical or biological pollutants, then OSHA requires PPE and containment. An experienced professional should be consulted if the remediators do not have expertise in remediation of contaminated-water situations. Do not use fans until it is determined that the water is clean or sanitary.
Assessing a Mold Problem
Before planning a remediation effort, the size and extent of the mold problem, and any ongoing moisture problems, should be assessed. Remediation generally can be divided into small (less than 10 square feet of mold), medium (10 to 100 square feet of mold), and large jobs (more than 100 square feet of mold). A remediation manager should be selected for medium or large jobs. An experienced health and safety professional in remediation projects should be consulted, particularly on large or complex jobs.
Questions to consider before starting remediation:
• Are there existing moisture problems in the building?
• Have building materials been wet longer than 48 hours?
• Are there hidden sources of water, or is the humidity high enough to cause
• Are the building's occupants reporting musty or moldy odors?
• Are the building's occupants reporting health problems?
• Are building's materials or furnishings visibly damaged?
• Has maintenance been delayed or has the maintenance plan been altered?
• Has the building been remodeled recently, or has its use changed?
• Are consultations with health professionals indicated?
The highest priority in a remediation is to protect the health and safety of the building's occupants and the remediation workers. Remediation plans vary according to the size and complexity of the job. The plans may require updating if circumstances change or if more extensive contamination is discovered.
The remediation plan should include:
Mold Remediation Procedures
A variety of methods is available to remediate damage to buildings and furnishings caused by moisture-control problems and mold. The procedures selected depend on the size of the moldy area and the type of contaminated materials. Budget may also be a concern. The methods presented in this section outline one approach; some professionals may prefer to use other methods. If possible, remediation activities should be scheduled during off-hours when building occupants are less likely to be affected.
Cleanup methods may include:
Wet vacuums ("wet-vacs") and water-extraction vacuums are designed to collect water. They can be used to remove water that has accumulated on floors, carpets and hard surfaces. Wet vacuums should be used only when materials are still wet; otherwise, they may spread mold spores. Wet vacuums alone will not dry carpets. Wet carpets must be pulled up and dried, and then reinstalled. The carpet padding must also be dried. The tanks, hoses and attachments of wet vacuums should be thoroughly cleaned and dried after use because mold and mold spores may stick to their surfaces.
Mold can generally be removed from hard surfaces by wiping or scrubbing with water and detergent. Always follow the cleaning instructions on product labels. Surfaces cleaned by damp wiping should be dried quickly and thoroughly to discourage further mold growth. Porous materials that are wet and have mold growing on them may have to be discarded. Because mold will infiltrate porous substances and grow on or fill in empty spaces and crevices, completely removing mold can be difficult, if not impossible. Mold can also cause staining and other cosmetic damage.
High-efficiency particulate air (HEPA) vacuums are recommended for the final clean-up of remediation areas after materials have been thoroughly dried, and contaminated materials have been removed. HEPA vacuums are also recommended for cleaning up dust that has settled outside the remediation area. When changing the vacuum filter, workers should wear PPE to prevent exposure to mold that has been captured in the vacuum. (See Section 6 of this course.) The filter and contents of the HEPA vacuum must be disposed of into well-sealed plastic bags. Care must be taken to ensure that the new filter is properly seated on the vacuum so that there are no leaks.
Throw Away Damaged Materials
Mold-contaminated building materials that cannot be salvaged should be double-bagged in 6-mil or thicker polyethylene bags. The bagged materials usually can be discarded as ordinary construction waste. Packaging mold-contaminated materials in sealed bags before removing them from the containment area is important to minimize the spread of mold spores throughout the building. Large items that have heavy mold growth should be covered with polyethylene sheeting and sealed with duct tape before being removed from the containment area.
Biocides are substances that can destroy living organisms. The use of a biocide or a chemical that kills organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup. There may be instances, however, when professional judgment indicates their use (for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize an area; a background level of mold spores will remain, but these spores will not grow if the moisture problem has been resolved. If disinfectants or biocides are used, always ventilate the area and exhaust the air to the outdoors. Never mix chlorine bleach with other cleaning solutions or with detergents that contain ammonia because toxic vapors could be produced.
Note that dead mold is allergenic and may cause allergic reactions and other health effects in some individuals, so it is not enough to simply kill the mold. It must also be removed.
Buildings that have been heavily damaged by floodwaters should be assessed for structural integrity and then remediated by experienced professionals. Please note that the information covered in this course was developed for inspecting water damage and moisture/mold conditions caused by clean water, and not flood water, sewage or other contaminated water. Visit the the EPA’s website, which has an EPA Fact Sheet: "Flood Cleanup -- Avoiding Indoor Air Quality Problems."
During a flood cleanup, the indoor air quality in your home or office may appear to be the least of your problems. However, failure to remove contaminated materials and to reduce moisture and humidity can present serious long-term health risks. Standing water and wet materials are a breeding ground for micro-organisms, such as viruses, bacteria and mold. They can cause disease, trigger allergic reactions, and continue to damage materials long after the flood.
Mold Prevention Tips
• Moisture control is the key.
• Keep the building clean and dry. Dry any wet or damp areas within 48 hours.
• Fix leaky plumbing and any leaks in the building's envelope as soon as possible.
• Watch for condensation and wet spots. Fix the sources of moisture problems as soon as
• Prevent moisture due to condensation by increasing surface temperature or reducing the
moisture level in the air (humidity). To increase surface temperature, insulate or increase air
circulation. To reduce the moisture level in the air, repair leaks and increase ventilation (if
outside air is cold and dry), or dehumidify (if outdoor air is warm and humid).
• Keep heating, ventilation and air conditioning (HVAC) drip pans clean, flowing properly, and
• Vent moisture-generating appliances, such as dryers, to the outside, where possible.
• Maintain low indoor humidity, below 60% relative humidity (RH), and, ideally, between
30% and 50%, if possible.
• Perform regular building and HVAC inspections and scheduled maintenance.
• Don't let foundations stay wet. Provide drainage, and slope the ground away from the
• If you are not experienced with home and building repairs, you may want to consult a
professional when making necessary repairs, or for assistance related to mold-prevention
changes to your home or building.
First, if you see mold then there is simply no point in testing. Mold has to get removed regardless of what kind it is because ALL mold is a danger both to your health and structurally. True not all mold releases mycotoxins (the dangerous substance released by the overly scary black mold!), but all mold is an allergen simply because it is a foreign substance in your body. Some people are more susceptible to it then others but all of it is potentially harmful. Additionally, mold causes damage to the surface it’s on and can be as minor as surface staining or as major as structural damage.
The above paragraph is the official answer to mold testing. However, I’m going to let you in on a little secret that will make every mold remediation company cringe. If you see minor mold, meaning a few spots here and there, in an area that has had minor water intrusion it is worth getting a mold test complete to see if it is something you can fix. My personal (not professional) rule of thumb here is if there’s a minor amount then get a mold test and see if it’s toxic mold and needs chemical remediation by a professional removal company. If it tests as non toxic mold that is simply an allergen then a solution of bleach and removing the moisture can do wonders to save your budget. In this particular instance a $375 mold test can you save $2000 on remediation for something you can do yourself.
A mold test should be performed after the remediation process to ensure it is removed. Be wary of contractors that don't disclose this in the initial estimate because they will tack it on at the end as a hidden fee. When this happens two tests should be done, so don't get screwed paying for a bunch of services you don't need.
The two tests that must be done are an indoor air sample of the area with the remediation. So if you had mold in the bathroom get an air sample at or near that area not in the garage. The second sample that should be taken is an outdoor air sample as a control. This sample is taken to determine if the mold in the air is higher then that of the natural environment. Without this test you have nothing to compare it to so you will never know if it is high or low.
Some testing companies (yours truly) can be overly cautious and recommend 3 or 4 tests when you could get away with 2 or 3. I had a client just the other day that needed a mold test in the crawl space, but because the duct work was poorly installed I recommended one in the house as well. The client asked if she could do just the crawlspace. The simple answer here is yes you can but should you? the risk is really yours and my legal/professional recommendation is get 3.
Next on the list, walk in to your basement and see if it smells damp or musty. If it does there is a HIGH probability you have mold. Get it tested now before you have to pay thousands of dollars in the future to fix structural damage. If you have mold you can pay a relatively inexpensive price for a built in dehumidifier with a discharge pump and be done worrying about it.
On this same note if you smell mold (which has a very distinct oder) you need to have it tested. Your next question is why would I need to test it if I smell it? Doesn't that mean I have it? Absolutely you have it but in this case it still needs testing. You need to determine the degree of mold spores in the air. This will give a person trained in reviewing lab results an idea of the best remediation process. Basically if you smell mold you could have very minor mold that can be cured with the dehumidifier, or major mold and structural damage hidden and the ratio of mold in the air can give the tester an idea as to which. The other reason behind the test here is to know if it’s toxic so the remediation process can prioritize the steps to fix it. Bottom line here if it’s non toxic surface mold dry it out and cleaning it could be the $1000 fix for the problem; if it’s toxic mold it may need to be dried and chemically treated for $3000.
What about water damage? If you have a roof leak, a plumbing leak, HVAC condensation on the ducts, etc. Then you need a mold test provided 1 condition is met. Though mold can start growing immediately after water is introduced it isn't realistic to think that you would test high for mold because a water leak hit and was dried immediately.
A good rule of thumb here is if the water has been present more then 48 hours, or if you do not know the amount of time it has been going on then it is worth testing. Especially if you have a smell of mold in the air! First step address the leak and let it dry, 2nd step get an air sample taken to determine if you have mold present!
After mold remediation work has been complete an air sample should always be taken to determine if the counts have returned to normal. If the mold remediation was done properly this should be able to be complete within 24 hours. Unless you personally know and trust the contractor doing the work then hire a 3rd party inspector to check the house. As a quick tip the inspector should inspect the work completed before taking his mold sample, and that should be included in the price. Mold tests are expensive don't let a lazy inspector spend 5 minutes taking a sample only to walk away with your hard earned cash. A good inspector will check the work and verify visually that no mold is present, if it is he will schedule a re-inspection with you. Still an added fee since you have to pay him/her a $100 re-inspection fee but better then paying for a mold test to be done again. If it requires another inspection due to poor or unfinished work make the contractor pay the difference.
Sick, elderly or adolescence at home create strain on the family and their weakened immune system is not hardy enough to handle mold as a simple allergen in the air. If they are displaying symptoms of allergies then see a physician, though no mold expert should ever overrule the doctors advice, but it’s worth having the mold in your house tested so you can show the doctor the results and see if that better helps them determine a cause.
When you purchase a new home especially one with a basement or evidence of water damage it will justify the price in the long run. Most houses I inspect turn up negative, but the ones that test positive are always thankful they paid the money to do the test because the seller then pays for the mold remediation. A standard mold test is about $375 give or take depending on the number of samples to be taken, which is a bargain when looking at $10,000 worth of damage and repairs.
What about for renters? Before I was an inspector and a home owner I lived in a shanty 1 bedroom apartment. The ceiling had so much mold on it the tiles would cave in as I was lounging around my hovel. Had I known better at the time I would have had a mold test performed so that I would have documentation to prove that the apartment did not uphold their end of the lease (or the law since most states have language written to protect the tenant from health issues). This would have got me out of my lease without paying the $2000 early termination (extortion) fee, when it was time to leave. On that same note, and this is something relatively no one does but is a good idea if you can afford it, but getting a home inspection when you move in to a rental, can secure your deposit when it comes time to move out. If you’re planning on buying after your lease is up you could even get a discount by signing an agreement that the same inspector will do your house when you purchase.
People are always afraid to ask for things like that but as soon as you get over that fear you can start saving yourself money. Any inspector would jump on that since it guarantees them business in the future. I know I would even if it meant I did this inspection for a price to only cover my costs.
Bottom line here is landlords can screw you and bad ones will every time. Get the documentation in hand before it comes time.
Water damage can do some funny things; efflorescence, dirt, grime, algae, and even blown in insulation can all look like mold. That’s part of the reason why in certain circumstance it does make sense to test when it is visible. 9 times out of 10 the inspector will be able to tell the difference but sometimes when substances mix, for example when efflorescence and wet dirt get stuck to a wall, it can make it nearly impossible to tell visually.
The bottom line here is that you should not waste money on a mold test when it’s not needed. I don't recommend a mold test on every house I inspect and if an inspector is telling you that you need one, make sure it falls in one of these categories or get a second opinion. I often get new clients because someone called wanting a second opinion, some inspectors charge for a consult others don’t it really just depends. I never do as long as the person is in a geographic area that I service, or the consult is not overly time consuming. However, when a mold test is needed you should do it as quickly as you possibly can, before you cause more issues both structurally and to the residents. As a veteran I use a lot of military analogies so let me leave you with one; mold is devastating if left unchecked and I used to tell my Soldiers “when it’s time to strike, hit as fast as you can, as hard as you can, and be the first one to lay the hammer.”
I am a United States Army Veteran with over 10 years construction experience prior to my service. After my time in the military I enrolled in InterNACHI's rigorous course work to become a certified member and prepare for the National Home Inspectors Exam. I continue to push inspection courses and education, attaining and exceeding the required continuing education courses