Wednesday, June 19, 2024

How To Tell If Mold Is Active

What Causes A Basement To Smell Like Mold

Mold in Walls, Part 2

Basements tend to smell like mold because they are typically more damp which allows mold and mildew to grow and thrive. Being underground, a basement is not only susceptible to water intrusion at the foundation, but also warmer air entering the building envelope which leads to condensation.

If your like me and you grew up having an unfinished basement you probably have an odor that comes to mind

Just that damp/mustiness odor.

This not mean that your basement is dirty. You can vacuum and mop all you want but if you do not resolve the root of the problem it will do you no good.

As stated above, basements tend to have more moisture. It’s just the way it is.

It’s important to find out if moisture is entering your basement in other ways, as well. If you notice a broken seal on a window or a crack in the foundation wall, you may have found your musty culprit. You should also check to see if you have clogged rain gutters, French drains, sewer backups, leaky pipes or even a broken seal on your laundry dryer vent as these problems can all contribute to a musty basement.

How To Find Out If Mold Is Active Or Inactive

When you find this fungus in your home, your first instinct is to inspect it. You want to know exactly what youre dealing with.

But, before investigating further, know that contact with spores can be dangerous. You should take precautions, like wearing a respirator mask and gloves. These will prevent you from touching the spores or breathing in contaminated air.

Once you have a mask and gloves on, approach the fungus. Heres how to tell the difference between the active and dead mold.

Where Can Mold Be Found

Mold commonly grows where there are food and moisture sources. It also prefers wet climates, temperatures of around 70-80 degrees Fahrenheit, and poor air circulation. Here are some common food sources that mold can use to grow:

  • Wood beams
  • Drywall
  • Concrete
  • Heavy rains
  • Busted plumbing and/or HVAC components
  • Fire sprinklers
  • Appliance problems

If you have been affected by any water damage issues like the ones described above, it is a good idea to repair them as soon as possible. Failing to do so could lead to more severe issues.

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How Do You Keep Mold Out Of Buildings And Homes

Inspect buildings for evidence of water damage and visible mold as part of routine building maintenance, Correct conditions causing mold growth to prevent mold growth.

Inside your home you can control mold growth by:

  • Controlling humidity levels
  • Promptly fixing leaky roofs, windows, and pipes
  • Thoroughly cleaning and drying after flooding
  • Ventilating shower, laundry, and cooking areas.

How To Find Hidden Subfloor Mold

How To Tell If You Have Black Mold Growing In Your Home ...

Even if you have access to professional moisture detection meters, subfloor mold can be difficult to discover. Perhaps the easiest means of detecting a subfloor mold problem are seeing discoloration on vinyl flooring, warping or distortion in areas of flooring, or the presence of malodors.

Because many vinyl sheet materials have an organic paper backing, they are subject to mold growth. Mold will not grow on the vinyl, but the paper backing is an organic food source in this case. At times this mold growth causes a discoloration to the vinyls surface that can be seen by the homeowner.

As plywood and OSB wood products absorb moisture, their layers can separate or warp. Although this is not a guarantee that there is mold present, it is an indication of a potential problem area that requires further inspection.

The best way to determine whether a mold problem exists on a subfloor is to remove the finish flooring material. If the finish floor is carpet and pad, it can be easily disengaged and rolled back to expose the subfloor material. When vinyl tiles or vinyl sheeting is the finish flooring, it usually requires cutting a small piece of the vinyl out to see what lies underneath. When the flooring is hardwood or laminate, it may be possible to remove a small area to inspect beneath it, and then the hardwood or laminate can be reinstalled without doing permanent damage to the flooring.

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What Mold Smells Like

Mold has a damp, musty scentsimilar to what youd smell after opening an old book. In general, smell is not a good way to determine if there is a mold problem, says Laureen Burton, a staff chemist and toxicologist for the Environmental Protection Agency . The smell of indoor molds can differ depending on the type of mold, the surface on which its growing, and its source of moisture. Plus, she says, some people dont notice a smell at all.

The mold smell is caused by microbial volatile organic compounds , which are substances that are naturally produced by molds as they grow. The health effects of inhaling mVOCs are largely unknown, says Burton, although exposure to some mVOCs has been linked to symptoms such as headaches, nasal irritation, dizziness, fatigue, and nausea.

How To Interpret Your Mold Air Sampling Results

Due to popular demand, we have now added a service to interpret mold results for clients all over the globe. We provide review, interpretation and recommendations based on your mold results from other vendors and contractors. If you would like to engage this service, please use the contact us page or the link below to open an email, send us a copy of your results and we will respond with further information on how we can provide this service. This service will provide you with our most up to date published interpretations and site specific written interpretations on letterhead.

Many have asked me about how to interpret indoor air quality results. Since there is very little to be found regarding mold test results and air sampling interpretation on the web, I have decided to share this information with the world.

The following information is unofficial and opinionated in nature and is to be used as a guide to help understand mold concentrations. I have developed this guide through many hundreds of successful mold remediation projects. This guide shall not be considered a final conclusion of mold remediation requirements.

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Does Black Mold Smell Worse Than Regular Mold

Black mold refers to a type of mold called Stachybotrys which is just one specie. Because takes a large or hidden chronic leak for black mold to grow for a long time, the odor of black mold is typically more potent than other mold spore types.

The odor that Stachybotrys lets off can also be much more harmful to your health as well because the off-gassing can let off toxins.

But don’t be fooled, many other species of mold can cause an odor outside of black toxic mold.

Conditions Affecting The Genera Species And Rate Of Fungal Growth In Buildings

Why You Need a Mold Inspection — Not Just Mold Testing

The appearance of mold genera/species varies widely as a function of the growth substrate and moisture conditions.

Different species prefer different moisture levels and thus may appear on the same material such as drywall but at differentheights from the floor if that section of drywall was wet from the floor level. (Stachybotrys chartarum prefers very wet conditions andappears low on the wall.

In the extremely mold-contaminated building shown at left, the author tested every surface of every different type of building material found inside the structure.

The results were interesting: different mold genera/species had strong preferences for different materials .

Cladosporium and Ulocladium are often found somewhat higher on the same wall. Aspergillus sp. or Penicillium sp. often prefer still less wet conditions and may be found higher still or more uniformly spreadover a drywall surface as they may grow more readily in conditions of high humidity even if the drywall was not actually wet to the touch.

What produces mold growth on a building surface is the combination of this presence of omnipresentfungal spores available in the general environment, the presence of a building material that a particular fungus willgrow on , and the presence of appropriate conditions of moisture and, to a lesser degree, temperature andperhaps light or darkness.

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Differences Between Mold And Mildew

While mold and mildew are both fungi that need water, oxygen, and food in order to live and survive, they differ in a number of ways. Mold tends to have a higher profile and can even become fuzzy, while mildew is usually flat. Mold exhibits darker colors such as deep green and black mildew may begin as white, then turn brown or gray. Mildew converts to a white, powdery substance mold never does.

What Mold Looks Like

Molds are a type of fungus and can look like their fungal cousins, mushrooms and yeasts. Outdoors, molds can be seen gobbling up the dead organic matter on decomposing surfaces like fallen leaves and rotting logs indoors, house mold thrives in wet, humid environments like bathrooms and basements or anywhere that has recently flooded. There are thousands of types of mold, and their appearance can vary depending on the type of mold and where its growing.

The most common indoor molds are Cladosporium, Penicillium, Aspergillus, and Alternaria, according to the Centers for Disease Control and Prevention . Black mold, or Stachybotrys chartarum , is also sometimes found in homes and other buildings. This greenish-black growth can grow on fiberboard, paper, dust, and lint, particularly in areas that may have recently flooded or suffered other types of water damage. While black mold can certainly look scary, the CDC says that Stachybotrys chartarum isnt any more harmful than other types of mold.

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Moving Your Personal Belongings In A Safe Place

If, for example, you have white mold on the floor joists in your crawl space, your personal belongings in the surrounding area may also become damaged by the mold. To prevent this, your restoration company should move your personal belongings to a separate part of your house during the remediation process.

Are Dry Mold Spores Harmful To Human Health


People usually think that mold is harmless unless you touch it or eat it. However, because mold spores are microscopic in size, they can be easily inhaled, get trapped in our lungs, and cause a number of health problems.

There have been many studies conducted on the topic of mold and its potential health effects. Various agencies such as U.S. Centers for Disease Control and Prevention, the Institute of Medicine of the U.S. National Academy of Sciences, the World Health Organization and Health Canada agree that exposure to mold at home or at work increase the chances of getting a respiratory disease.

Since some molds produce allergens and others potentially toxic substances, inhaling the spores can cause:

  • Allergic reactions
  • Respiratory problems like asthma and wheezing
  • Irritation of eyes, nose or skin
  • Mental confusion
  • Fatigue
  • Headaches

Once again, it is not enough to kill the mold, but also to remove it totally.

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Ozone To Remove Smell

Ozone generators have become popular removing indoor odors in recent years. It has been said to be very effective according to manufacturers of the product. There is no scientific evidence to back this up and can be harmful to humans when inhaled or ingested. Additionally, no government agency recommends this be used in a location when occupied.

If you use an Ozone generator that states it’s EPA approved, this can be misleading. The EPA states this about Ozone:

Several brands of ozone generators have EPA establishment number on their packaging. This number helps EPA identify the specific facility that produces the product. The display of this number does not imply EPA endorsement or suggest in any way that EPA has found the product to be either safe or effective.

Please Note: EPA does not certify air cleaning devices. The Agency does not recommend air cleaning devices or manufacturers. If you need information on specific devices or manufacturers.

If you decide to use Ozone to remove odors in the home, make sure you are not staying there!

Develop A Mold Redemption Plan

Your mold specialist should provide you with information, specific to your property, on how the process of removing mold from floor joists will work. You can then submit this along with other documentation, like a mold test done by an industrial hygienist, to your insurance company. Depending mainly on your insurance policy and how the damage occurred, it is possible that your insurance may at least partially cover the mold remediation work.

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Why Does Subfloor Mold Develop

Subfloor mold usually develops due to an undetected moisture intrusion between the different layers of flooring, especially when the finish flooring is sheet vinyl, laminate flooring, or ceramic tile. I say especially only because if your flooring is carpet, the moisture is much more apparent and quickly and easily discovered.

Unwanted moisture can originate from many different sources such as a slow supply line leak on a faucet or toilet. Another common, and usually harder to determine source of excess subfloor moisture, is a faulty wax ring seal under a toilet that allows water to escape from drainpipes and affect the subflooring. Anytime you have warm temperatures , a source of water, and organic food materials like plywood or OSB, it is possible for mold to develop.

How Do Molds Affect People

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Exposure to damp and moldy environments may cause a variety of health effects, or none at all. Some people are sensitive to molds. For these people, exposure to molds can lead to symptoms such as stuffy nose, wheezing, and red or itchy eyes, or skin. Some people, such as those with allergies to molds or with asthma, may have more intense reactions. Severe reactions may occur among workers exposed to large amounts of molds in occupational settings, such as farmers working around moldy hay. Severe reactions may include fever and shortness of breath.

In 2004 the Institute of Medicine found there was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, cough, and wheeze in otherwise healthy people with asthma symptoms in people with asthma and with hypersensitivity pneumonitis in individuals susceptible to that immune-mediated condition.

In 2009, the World Health Organization issued additional guidance, the WHO Guidelines for Indoor Air Quality: Dampness and Mould pdf iconexternal icon pdf icon. Other recent studies have suggested a potential link of early mold exposure to development of asthma in some children, particularly among children who may be genetically susceptible to asthma development, and that selected interventions that improve housing conditions can reduce morbidity from asthma and respiratory allergies.

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Mold And Mildew Health Concerns

The health of both humans and pets may be affected by the presence of mold and mildew in the home. While some people may not be affected at all, others who are especially sensitive may experience symptoms such as itchy eyes, wheezing, or a runny nose. People with asthma or allergies will feel the most severe reactions to mold and mildew.

Solve The Moisture Issue

As mentioned before, moisture is one of the primary factors that mold requires to grow. That being said, if you have mold in your property, it is important that your mold remediation contractor find the moisture source and repair it. They will often use a moisture meter like the one found on our recommended products page in the detection process.

Read Also: How To Treat Black Mold On Drywall

Why Does Mold Cause A Pungent Odor

Mold growth itself does not smell bad. It is the off-gases that are let off by mold growth called Microbial Organic Compounds .

The dank musty odor signifies the presence of microbial volatile organic compounds . Traditional volatile organic compounds are mainly industrial made chemicals with low molecular weights, high vapor pressure and low water solubility. MVOCs are released from metabolic processes of decay agents like fungi, bacteria and biofilm. The off gassing of MVOCs include a wide range of alcohols, ketones, aldehyde, esters, carboxylic acids, lactones, terpenes, aromatic hydrocarbons, sulfur and nitrogen compounds.

You don’t need to know scientifically how MVOC’s are formed, however, you must know it is caused in most causes by water damaged porous materials. This could mean drywall, clothes, flooring, etc.

Bottom line is this:

If you have had a leak in your home that was not dried up properly or maybe a hidden leak that led to mold growth


You have identified mold as the source of the moldy smell in your home.

A Mycologist’s View On Setting An Age On Mold In Buildings

Do these pictures suggest mold is growing behind walls ...

Mycologists indicate and field experience by property inspectors confirms that fungal growth can occur in a building over abroad surface and quite rapidly, in as short a time as 2-3 days in some conditionsand they add that it is not very reliable to guess at the “age” of a given mold colony.

Of course there are exceptions: some fungal growth such as “tree ears” and hard fungi produce slow-growing and durable structures over many years – the larger their size the older they are.

But in general, mycologists are precisely correct: looking at a sample mold itself does not easily permit us to guess how long mold has been present on that surface.

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Isolate The Affected Area

Isolation is a key factor in reducing the chances of mold spreading to other parts of the property during the remediation process. For a small mold issue, your contractor will likely only be required to shut all the doors and windows that are near the contaminated area. If there is a larger amount of mold present, your contractor will need to additionally block off any contaminated areas with polyethylene sheeting.

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