🧪 Part 3: How We Detect Mold Understanding the Tools, Techniques, and Triggers Behind Mold Detection

Mold isn’t just unsightly—it’s a biological contaminant that can compromise indoor air quality, damage building materials, and trigger health concerns. At Altamaha Home Inspections, we treat mold detection as both a science and a responsibility. In this post, we’ll walk you through how we detect mold, when sampling is warranted, and what limitations every homeowner should understand.

👀 Visual Inspection: The First Line of Defense

Mold detection starts with the senses. Our inspectors are trained to spot subtle signs that often go unnoticed:

•            Stains and discoloration: Black, green, or white blotches on drywall, ceilings, or baseboards may indicate mold colonies.

•            Warping or bubbling: Moisture intrusion can cause materials like wood or vinyl to deform—often a precursor to fungal growth.

•            Musty odors: Mold emits volatile organic compounds (VOCs) that produce a distinct earthy smell, especially in enclosed spaces like crawlspaces or attics.

While visual cues are helpful, they’re not definitive. Mold can hide behind walls, under flooring, or inside HVAC systems. That’s where technology comes in.

💧 Moisture Detection: Finding the Source

Mold needs moisture to thrive. Detecting hidden dampness is key to understanding whether conditions are conducive to growth. We use:

•            Moisture meters: These handheld tools measure the percentage of water in building materials like drywall, wood, and concrete.

•            Hygrometers: Used to assess relative humidity levels in the air. Mold often flourishes when indoor humidity exceeds 60%.

•            Infrared cameras: These thermal imaging devices reveal temperature anomalies that may indicate hidden leaks or condensation behind walls.

Moisture mapping helps us pinpoint problem areas and determine whether mold is likely to be active or dormant.

📊 Particle Meters: Measuring the Invisible

When mold is active, it releases microscopic spores into the air. These spores aren’t visible to the naked eye, but they can be detected using particle meters—a powerful tool in our mold detection arsenal.

🛠️ What Is a Particle Meter?

Extech VPC300 Particle Counter

A particle meter (also called a laser particle counter) measures the concentration of airborne particles by size. It uses a laser beam to count particles as they pass through a detection chamber, categorizing them by diameter—typically in microns (µm).

•            Mold spores generally range from 2 to 10 µm, so we focus on particle counts in that size bracket.

•            The meter provides a real-time snapshot of indoor air quality, showing how many particles are present per cubic meter or liter of air.

✅ Advantages of Particle Meters

•            Non-invasive: No need to disturb surfaces or collect samples—just turn it on and monitor the air.

•            Immediate results: Unlike lab-based sampling, particle meters give instant feedback.

•            Area comparison: We can compare readings from different rooms to identify hotspots or migration patterns.

•            Pre-screening tool: Helps determine whether further sampling is warranted.

⚠️ Limitations and Considerations

•            Not mold-specific: Particle meters detect all airborne particles—dust, pollen, smoke, pet dander—not just mold spores.

•            Environmental sensitivity: Readings can spike due to vacuuming, cooking, or open windows, so we control for these variables during testing.

•            No species identification: Unlike lab samples, particle meters can’t tell us what kind of mold is present.

That’s why we use particle meters as part of a layered approach, not a standalone diagnostic.

📈 Interpreting the Results

Here’s how we make sense of the numbers:

•            Baseline comparison: We take readings in unaffected areas (e.g., outdoors or in clean rooms) to establish a baseline.

•            Elevated counts: If a room shows significantly higher particle counts in the 2–10 µm range, it may indicate active mold spore release.

•            Trend analysis: We look for patterns—are counts higher near water-damaged materials, HVAC vents, or crawlspaces?

For example, if a living room shows 15,000 particles/m³ at 2–5 µm, while the outdoor baseline is 2,000 particles/m³, that’s a red flag. Combined with moisture and odor findings, it may justify air sampling or remediation.

🧠 How It Applies to Mold Detection

Particle meters help us:

•            Validate client concerns: If someone reports allergy symptoms, we can check for elevated particle loads.

•            Prioritize inspection zones: High readings guide us toward areas needing deeper investigation.

•            Document indoor air quality: Useful for insurance claims, tenant disputes, or post-remediation verification.

In short, particle meters give us a quantitative lens on what’s floating in your air—and whether it’s time to dig deeper.

🌬️ Air and Surface Sampling: When We Go Deeper

Mold Test Kit (Air and Surface)

If visual and moisture assessments suggest mold activity—or if clients have health concerns—we may recommend sampling. This involves collecting physical evidence for lab analysis:

•            Spore traps (air sampling): These devices pull air through a cassette that captures airborne mold spores. Results are compared to outdoor baseline levels to assess indoor contamination.

•            Swabs and tape lifts (surface sampling): Used to collect mold from visible growth areas. Swabs are ideal for irregular surfaces; tape lifts work well on flat materials like drywall or wood.

•            Bulk samples: Occasionally, we remove small sections of material (e.g., carpet, insulation) for lab testing when contamination is suspected deep within.

Sampling is not always necessary—but when it is, it must be done with precision and purpose.

🧑‍⚕️ When Sampling Is Warranted

We follow industry standards to determine when mold sampling is appropriate. According to the IICRC S520, EPA Guidelines, and ASTM D7338-14, sampling is typically warranted when:

•            Health concerns are present: If occupants report respiratory issues, allergies, or unexplained symptoms, sampling can help identify airborne irritants.

•            Insurance or litigation is involved: Objective lab results may be required for claims, disputes, or legal documentation.

•            Remediation verification is needed: Post-remediation sampling confirms that mold levels have returned to normal and that cleanup was successful.

•            Unusual or hidden mold is suspected: If mold is suspected in inaccessible areas (e.g., wall cavities), sampling can guide remediation strategy.

We never sample just to “see what’s there.” Every test must have a clear purpose and follow best practices.

⚠️ Limitations and Best Practices

Mold detection is not foolproof. Here’s what every homeowner should understand:

•            False positives and negatives: Airborne spore levels fluctuate with weather, ventilation, and occupant activity. A single test may not reflect long-term conditions.

•            Lab interpretation matters: Not all mold is harmful. Labs identify species, but context determines risk. For example, Stachybotrys chartarum (black mold) is more concerning than Cladosporium.

•            Sampling is a snapshot: Results reflect conditions at the time of testing. Ongoing moisture or ventilation issues can cause mold to return.

•            DIY kits are unreliable: Over-the-counter mold tests often lack calibration, chain of custody, and professional interpretation.

At Altamaha, we follow ASTM D7338-14 protocols to ensure sampling is justified, documented, and interpreted correctly.

🧠 Educating Our Clients

We believe mold detection should empower—not alarm—homeowners. That’s why we:

•            Explain every tool and technique we use.

•            Provide clear, jargon-free reports.

•            Offer guidance on remediation, prevention, and maintenance.

•            Use visuals and branded resources to make mold education accessible for all ages (yes, even our junior inspectors!).

Our mold detection protocols are grounded in respected industry standards:

•            IICRC S520: Standard for Professional Mold Remediation

•            EPA Mold Remediation Guidelines

•            ASTM D7338-14: Standard Guide for Assessment of Fungal Growth in Buildings

These resources help us stay current, compliant, and client-focused.

🏁 Final Thoughts

Mold detection is more than spotting stains—it’s about understanding the biology, the building science, and the human impact. Whether we’re inspecting a historic home or a new build, our goal is the same: to protect your health, your investment, and your peace of mind.

If you suspect mold or want a proactive assessment, reach out to Altamaha Home Inspections. We’re here to help—one inspection at a time.