Causes and effects of mold damage

What is mold?

Before we get into how to detect mold or measure mold levels here in Nashville, Tennessee, it’s important to understand what mold actually is. Mold is a type of fungus that spreads and grows by producing spores. These spores are smaller than the eye can see, with over one million fitting on a pinhead. 

Mold is naturally occurring and critical to the ecosystem because it breaks down organic matter, recycles nutrients, and feeds certain insects and bacteria, making the base of many ecosystems. 

So mold spores are always floating around in the air, waiting for a moisture-rich food source to attach to and start reproducing. In homes, its favorite sources are the paper on your drywall and wood. 

Mold is surprisingly adaptable and very hard to kill. Most people think mold spores need warm temperatures to survive, but when it gets cold—or even freezing—mold just goes dormant. The only temperature that consistently kills mold spores is 140°F. 

What are mycotoxins?

If you’ve done any research on mold ore are thinking about mold removal, you’ve probably come across the word mycotoxins. Mycotoxins are chemicals produced by mold, either as a byproduct (think mold burps) or as a defense mechanism when it feels threatened. These toxins are not alive but are often more dangerous than the mold itself. 

These toxic chemicals can cause serious health issues when ingested, inhaled, or absorbed through the skin. If you have serious health issues (beyond allergy-like symptoms) and think mold is the cause, you’re likely dealing with mold spores that emit mycotoxins like Stachybotrys. 

Not all molds produce mycotoxins but you also don't need mycotoxins to have major respiratory issues or allergies. You can view our guide to mold sickness to see how these issues are correlated.

What is the most common cause of a mold issue?

If you're reading this you are probably trying to figure out if you need mold remediation or restoration. Before you proceed with a costly project on your property you should understand what typically causes indoor mold issues.

Across all of our mold tests and inspections in Nashville, TN, we’ve seen most mold issues start from one of three sources: 

1. Major water damage not dried or cleaned up fast enough – If you’ve had a pipe burst, tub overflow, or major flooding and didn’t fully address it within 24 hours, there’s a good chance mold has found a home somewhere inside your house where the moisture reached or got in drywall gypsum.

2. Minor water damage left unaddressed over time – Many homes have a small leak or water damage under the sink or from an HVAC system. It may not seem serious, but over time, mold will find the moisture and start building a nest and hurting your indoor air quality.

3. Crawlspace or basement water – Proper drainage around the home is critical. Especially with our crazy Nashville TN rains. Without grading that slopes away from the house, or drainage like French drains, your crawlspace or basement may sweat or collect water—becoming a magnet for mold damage. We often find hidden water damage that owners haven't addressed for years.

Mold inspections in Nashville, TN

Before we get into testing, it’s worth saying a few words about mold inspection services in Nashville because we consider them part of the testing process. Ideally, the person who tests your home is also licensed to do a mold inspection. One of the best mold “tests” out there is still the eyes of someone seasoned in mold inspection services. 

An expert doing a mold inspection will know where to look for mold damage based on your home’s layout, orientation (mold tends to grow on the north side, away from sunlight), and moisture readings. With experience and visual deduction alone, they can often inspect and identify a mold problem without running a test.

Mold testing guide in Nashville, TN

Before diving into the specifics on the signs of mold or measuring your indoor air quality, it’s important to know that every mold test—no matter how extensive—has limitations. In fact, 50–75% of mold tests across the country (including Tennessee) result in false negatives. This is even when you remove the inconsistencies of at home mold testing kits. (Source) 

This is why a comprehensive mold inspection and review of the home is so important prior to any restoration efforts. A visual mold inspection looking for signs of mold, a clear understanding of the home’s history of water damage, and health symptoms are critical to understanding what’s really happening. Even when using multiple test types or locations to detect mold, false negatives are common.

Why are there so many false negatives?

There are several reasons Nashville home mold tests come back clean when a problem exists that needs mold removal:

That said, there are things you can do to improve the accuracy of a test. For example, the mold tester can “disturb the air” using compressed air to kick up settled spores—or irritate “happy” mold into sporulating. The tester should also inspect the home to find the right sampling location and make sure all air purifiers have been off for at least a few hours.

Most common types of mold testing in Nashville, TN

There are three main types of mold testing in Nashville. Each has its pros and cons: 

‍1. Air mold test using a spore trap
‍This pulls a set amount of air through a small cassette, which is then analyzed by a third-party lab. 
- Pros – Most common type of air quality testing in both residential and commercial properties. Fast results. Can detect both visible and hidden mold. Identifies different mold types. 
- Cons – Only captures airborne spores during the brief testing period. High false negative rate which can lead you to not proceed with mold removal. 

‍2. Surface mold test using tape or swab
‍A sample is taken from visible mold damage using tape or a large swab. 
- Pros – Tells you exactly what type of mold has infected your mold damage area and help direct restoration efforts.
- Cons – Only works on visible mold in a specific location. Doesn’t indicate what’s in the indoor air. 

‍3. Dust testing for mold using ERMI
‍This test looks at the DNA in household dust collected around the edges of your home. 
- Pros – Reveals the history of mold in your home—even mold spores long gone.
- Cons – Doesn’t reflect current air quality and is not EPA-approved for diagnosis. Results make it difficult to decide what to do about mold removal or restoration.  

Note: There are also cultured and non-cultured variations of these tests, which can determine if mold is alive or dead.

How do I ensure I get the best possible air test results?

To get the most accurate results, you want the air test to reflect the true air quality in the room. We recommend doing the following at least 3 hours before your test:
- Turn off all air purifiers in the home
- Run your HVAC system
- Keep all windows closed

How bad is my mold test?

Almost everyone’s first question after air quality testing is: “Is this bad enough to proceed with remediation services?” That’s why we created a simple rubric to help you decide whether mold removal and restoration is necessary. 

‍If ANY of the following are true, we recommend remediation services in Nashville:

1. MoldScore over 150
‍This score ranks both the amount and type of mold found in your home.
‍
- 150+ = Elevated and probably needs to be remediated
- 250+ = Very concerning and needs mold removal right away 

2. Indoor mold levels are 50%+ higher than outdoor
‍This typically indicates a mold source in your home that will get worse over time if not addressed. Ideally this mold source is found when your professional went to inspect the building materials throughout your home but if not it may be hidden making it more difficult to remove the mold. This is especially trued during Nashville, Tennessee springs when outdoor mold levels are high.

3. Toxic 'marker mold' present
‍Toxins from these molds can alter brain chemistry, disrupt digestion, and even lead to long-term illness. They’re heavier and harder to detect—so if they show up, need to be remediated immediately.

4. Over 500 spores /m3 for any one spore type
It's really hard to say when mold is too much but experts generally agree that allergies can start at a concentration of 100 spores per m3, start to get consistent at 500 and turn into severe asthma at 4,000.

5. Expanding visible mold in the living space
‍You don’t need a test for this. If mold is visible and growing, it is highly recommended that you get it remediated. The humid Nashville Tennessee summers are just going to make things grow faster and increase any respiratory issues. 

6. Mold showed up in your blood or urine (or other diagnosis)
‍If you or a family member has tested positive for mold exposure, it’s likely coming from:
- Your homes mold
- Mold and mildew in your food or water
- Mold in your school or workplace 

If you feel worse at home and better when away, your Nashville home is likely the source.

Where can I get tested for mold exposure in Nashville, TN?

If you’re experiencing symptoms of mold sickness here in Nashville, one of the best first steps is to get a urine mycotoxin test. Some of the main providers are: 
- Great Plains
- Vibrant Wellness
- RealTime Labs  

These are often ordered by functional medicine practitioners, but you can also order a test online. 

If you’re in Nashville, Tennessee and want to skip the doctor visit, you can go to Any Lab Test Now and order a mycotoxin urine test. The cost is usually similar to getting it through a wellness doctor. 

There are also at-home kits from RealTime Labs and Vibrant Wellness. They ship to your door and include a doctor consult to go over the results—usually in 7–10 business days. 

Even these tests can have false negatives, especially if your body isn’t excreting toxins well. But they’re often more accurate than environmental tests. 

Mold testing is just a part of your mold detection strategy

Hopefully this helped clarify that mold testing is just one part of a full diagnosis as you think about if you need mold remediation and restoration. mold testing should be paired with inspection, health symptoms, and home history. 

If you’re in the Nashville area and want help figuring out what to do next, call us anytime at (615) 486-2217.