You don’t need to be an expert to find some basic signs of mold. With some level of understanding on mold signs and growth, you can do some initial check before you call an expert. Let’s see how to find mold in your house or building and discuss about the signs, causes and tests.
Ways to find signs of mold:
There are two simple and quickest ways to find mold before you go for advance level testing. One is visual, inspection by just looking around in dark areas or confined spaces. The other one is by smell or odor.
Visual Inspection for mold:
The easiest way to check for mold is visual inspection first. Check for any wet areas like bathrooms, kitchen or basement. You should also check areas having water leakage or previously having leakage issues.
Just be aware that mold is not always black! Mold can occur in different colors. It can occur in white, pink, green, blue, yellow and black color. These are most commonly found colors.
There are different scientific names of mold. The experts know them by types of species. The common ones are aspergillus, Cladosporium and Stachybotrys chartarum (atra). Each one has a different color.
While doing visual inspection, keep in mind the two scenarios. One is visible mold growth and the other one is not visible which is mold spores. You may not see the spores by normal vision, but they have a potential to grow as mold. Therefore, visual inspection is not enough every time.
Black mold
Black mold is one of the most toxic ones. Its scientific name is Stachybotrys chartarum (atra). The black mold is either black or dark green in color and it can cause severe health problems.
Discoloration, peeling paint, cracks are signs of black mold. Yellow stains on walls can be a start of black mold growth. Black mold can be found on drywall, back of drywall in leaky basements, behind kitchen counters, sink cabinetry, carpet and carpet sub floors.
Another type of black mold is Memnoniella just a different structure compared to Stachybotrys.
White mold
White mold is not very easy to detect because of its color. Aspergillus, Penicillium, and Cladosporium are some of the common white mold.
White mold is mostly found on furniture, foot ware, water damaged walls, attic, floor joists in the crawl spaces. Black mold is on wet and saturated surfaces while white mold is in moist and damp air spaces with limited fresh air flow.
Green mold
Green color of mold is common in many species. Penicillium, Cladosporium, and Aspergillus are found in green color. The same species are also found in blue color too. Green mold is usually found on wet spongy areas. Most common spots are carpet, mattress and insulation.
Yellow mold
Yellow mold is also seen in buildings quite often. Serpula lacrymans is one of them. Like termite, this mold will eat up the building structure. It is little scary but true. This mold can be found on furniture with yellow spots. Some old wooden buildings are reported to be destroyed in past due to this mold.
Aspergillus is another type with lots of different species. Aspergillus can be found in areas with heavy water damage.
A type of mold commonly known as slime mold is also yellow in appearance. They are mostly single cells structure and appear like a yellow slime. This type of mold grows in decaying wood.
Orange mold
Fuligo septica is the mold with a distinct orange color. Orange mold also has a slimy and spongy look same as the yellow mold.
In your house, you should look for humid areas with wooden structure. Wet windowsills are one of them. The other location prone to this type of mold is shower and bathrooms. In the shower area, you may find them on tile joints. At the tile joints, they grow on top of cement based grouts with help of water and minerals from shampoo or soap. The next spots to locate are the kitchen and attic.
Fuligo septica is also known as “Dog Vomit Slime Mold”. This is more commonly found on mulch in the garden.
The orange mold can grow together with another common mold like black or white. They start growing like small dots and then grow like clumps of slime.
Brown mold
Brown mold is a type of mold which is rare inside buildings. They are also not very harmful for human health, but they can damage the building components easily.
Pithomyces is one of the types that can occur in brown color. They usually grow outdoors in soil or leaves. Inside the building, you can find them on damp drywall or wallpaper. Pithomyces can enter your house in form of dust or mixed with dust. So, look for any dusty areas in your house to locate a brown mold. Other potential areas are carpet, ceiling tiles and mattress.
Detection of mold by smell:
How to find mold by smell? Some common molds have a typical bad smell which you can not ignore. Finding distinct odor from mold can be one of the basic detection methods. You can not only rely on this to confirm the mold presence, but it helps!
Just like different colors, mold can produce variety of odors. Mold is a type of fungi and most of them can travel in air. As it grows in confined spaces with less air moment, you can feel the moist and the typical pungent smell.
Although odor is not considered a reliable measure to confirm the presence of mold, a strong musty smell can at least alarm you for a potential danger. Most of us can feel the change in air quality while entering a basement. The humid air mixed with distinct smell is what we usually feel in the basement.
The ability to smell is differs person to person. Also, many types of mold have no smell at all. That’s the reason why mold is sometimes more dangerous as it can easily cheat your senses of vision and smell.
In short, the smell of mold is described by different “smell like” things. Some people smell like wet wood, rotten wood or paper. Some feel the smell like socks. A wet soil or earthy smell. Some smell it like an alcohol too.
Causes of mold growth:
If certain favorable conditions are met, most molds can start growing within 1 or 2 days. Let’s review these conditions one by one in detail. The growth of mold is caused by combination of this conditions. For example, darkness combined with humidity. It is never a single factor causing the right environment but a mix of them in varying intensity.
Presence of mold spores:
You may have the ideal environment in your house for the mold, but it may still not cause any mold growth because the mold spores cause the mold growth. Mold spores travel in air and enter your house. It can also use other medium like dust, leaves, leakage in the building etc. You can not see them with naked eyes.
Mold spores can range in size of 3- 100 microns. Just for a better understanding, you can compare it with human hair which is around 75 microns!
In short, presence of mold spores is important for mold growth to start.
Humidity:
Moist air or humidity is one of the biggest culprits causing mold growth. Relative Humidity (RH) of 60% of more is best for mold. In other words, keeping RH low between 30-50% can save you from mold danger.
We know that humidity causes mold but what causes humidity?
Humidity is level of moisture held by air. Most of the moisture issues are associated with ventilation in your house or building. Poorly ventilated buildings have moisture and humidity issues causing mold growth at some stage.
There are two major factors creating humidity in your house. One is moisture or water seepage from outside entering your house. And the second is your house not letting the moisture or water to go out properly.
Using the porous building materials, moisture tries to enter from surrounding. Vapor barriers help to protect in this situation. A water leakage from roof or water seepage due to a wrong positioning of downspout are a few examples of how water gets in.
Improper ventilation of your heating and cooling systems will cause moisture to stay. Also, improper venting of appliances adds more humidity.
Ultimately, these issues help mold to grow fast. Because moisture is held in confined spaces, you sometimes do not see the mold on face of drywall or carpet, but you find it on the back of it.
Dark Spaces:
Most molds grow in dark spaces. Some molds or fungi can be found outside in garden or soil or on leaves too.
Most of the mold found inside the house find it convenient to grow in dark. In other words, these molds can not withstand UV light. The ultraviolet light, whether natural or artificial can easily kill the mold. The UV light hinders the growth by inactivating and breaking the DNA structure of microorganisms.
The good effects of UV lights have been scientifically proven. One of the best examples is their use in latest AC Units. The condensation in AC Units cause dampness and mold issues. The UV light will help prevent it. The UV light purifies air and it can be installed in return air duct to sterilize the air handling coil in big units.
Temperature:
As mentioned earlier, no single factor can cause the mold growth, it is always a combination. Spaces with a temperature of 20-21 degrees Celsius (68- 70 degrees Fahrenheit) or more can easily get affected with mold issues.
Let’s say a space with 20 degrees Celsius (68 Degree Fahrenheit) temperature with Relative Humidity of 85- 95% with presence of mold spore and food will easily see a growth in 3 to 7 days!
Food for mold:
Mold is a living organism. In other words, there are many such living things you may find in your house who don’t even pay you the rent!! They even cost you money if you don’t kick them out.
All living things need something to eat or prey on. And mold needs organic food. Organic material is carbon-based material mixed with some other natural elements. Wood, leaves, paper, fabric, soap are some common organic materials.
A small droplet of soap can be a sufficient amount of food for the mold to grow in shower or bathroom. Food particles behind kitchen appliances can also serve the mold as an organic food. The thin layer of paper on drywall, carpet and carpet cushion, wallpaper, wood furniture are some other important food sources.
Mold can grow on any surface, but they prey on organic things. For example, a small bunch of organic dust on concrete can help mold grow on concrete. So, don’t be mistaken by expecting mold only on organic materials.
Mold Detection Tests:
You can do some basic testing yourself or hire a certified professional for a sure shot result. Also, if mold is detected, a post testing is recommended to confirm it is completely gone. Let’s see how to find mold with some advance level testing.
The professional mold detection can be classified under four stages.
- Visual assessment
- moisture content readings of building materials
- Air sampling
- Surface sampling.
Visual Assessment for mold:
A thorough visual assessment will include a check for water damaged surfaces along with signs of mold. It will also include a check for musty-like odor.
Some surfaces congaing cellulose (drywall, ceiling tiles, wallpaper) are thoroughly inspected for stains or discoloration. The paint surfaces are inspected for cracks, peeling etc. Drywall can be checked for signs of crumbling. Floor is examined for signs like cupping or swelling.
The quality of visual assessment is affected by limited accessibility. For example, you can check the face of the wall, but you can not see behind it until you rip off the wall, full or part.
Moisture content readings of building materials:
Mold has a direct connection with moisture and wetness. There are variety of moisture meter used for this test. Some porous building materials can be thoroughly checked for moisture by penetrating. And solid materials like concrete or plastic can be tested for surface moisture.
The moisture meter will give you details of materials with “At Risk” levels.
As mold needs a combination of favorable factors, testing needs a combination of tests. The moisture content test has some limitation. You can measure the moisture content of drywall and it may appear dry. But mold can still be present there if the wall was previously wet and dried out eventually.
Air sampling of mold:
As the name suggests, a sample of air is captured from the area with mold suspected. Rooms with heavy mold growth will have a lot of mold spores in air. The mold spores can be found in the air sample test to confirm the presence of mold.
The small container is called a “cassette” through which the air will pass. Also, the particles/ spores are trapped on an adhesive coated slide inside. The technicians use a pump to ensure the air flow rate of about 15 liter per minute (lpm).
This samples are tested at a laboratory with a magnifier to inspect micro size spores. The results are counted in spores per cubic meter.
Surface sampling for mold testing:
Surface sampling is done by an adhesive tape or bulk sampling.
Tape Lift Samples:
Sometimes there are stains seen on surfaces indicating mold growth. Though, it may appear like mold, you can not be 100% sure until you verify. With the help of clear adhesive tape, you can stick the tape to a surface and remove it to take a sample. The mold or spores if present, will stick to the tape. The tape is then placed inside a plastic seal-able bag and taken to a testing lab.
Bulk Samples:
Bulk samples are collected by physically removing a part of the building material in question. Same as tape the samples, these samples are kept in a seal-able bag to transport it to laboratory.
The surface samples are analysed in the lab under microscope. The magnification is like 400 times or more! Each type of mold detected is identified by the lab and described by species name. Also, they are listed by lab in rank order.
Hope the above details helped you to get an answer on how to find mold. But, mold detection and removal is definitely not a DIY project. There are hundreds of different types of mold and exposure to some of them without proper knowledge can harm your health. So, it is advisable to hire a certified professional to test and experienced contractor to remove the mold and rebuild affected areas.
Read More on Mold:
The 12 most common molds- where can they grow inside the house?
18 types of mold- less common indoors, but you shouldn’t ignore them.
