How to Find a Healthy (Mold-Free) Home When You’re Mold-Sensitive By Dr. Terri Fox, The Medical Detective For people living with mold illness, finding a safe home is not just about comfort—it’s about survival. I’ve seen too many patients worsen after moving into a “clean” house that turned out to be a mold minefield. Whether you’re buying or renting, you must become a mold detective to avoid a hidden health hazard. In this guide, I’ll walk you through how to assess a home for water damage, what to ask about its history, the tools you can use (like ERMI testing and hiring an IEP), and why even brand-new homes can be risky. Let’s get started. 1. New Doesn’t Mean Safe: The Myth of the Modern Home It’s tempting to believe that a newer home equals a healthier home—but that’s not always the case. In fact, many newer homes are built too tightly sealed, which means there’s poor air exchange. Without proper ventilation, humidity builds up—creating the perfect environment for mold to grow inside walls, HVAC systems, or even under flooring. Even more concerning: the wood used to frame new homes often sits out in the rain or snow for weeks—or even months—during construction. This untreated lumber can absorb moisture, and if it’s enclosed in drywall before fully drying, it becomes the perfect hidden breeding ground for mold. While the home might look pristine at closing, you could be walking into a structure already contaminated from the inside out. Add to that the fact that many newer homes rely on cheaper, mold-prone materials like OSB (oriented strand board) and paper-backed drywall, and it’s easy to see why new construction isn’t necessarily safer for mold-sensitive individuals. 2. Know the Signs: What to Look For During a Walkthrough Before you bring in professionals, do your own detective work. Keep an eye out for: Water stains or discoloration on ceilings and walls Musty or earthy smells, especially near bathrooms, basements, and HVAC vents Buckling floors or baseboards, which may indicate past water intrusion Peeling paint or bubbling drywall Visible mold—even a tiny patch can indicate a larger problem Humidity levels—use a hygrometer to make sure levels stay under 50% 3. Ask the Big Questions: Uncover the Home’s Water History A clean-looking house may still have a dirty past. Always ask: Has the home ever experienced flooding, leaks, or plumbing issues? Were any insurance claims filed related to water damage? Were remediation efforts documented and professionally completed? How old is the roof, HVAC, and plumbing system? Are there sump pumps, dehumidifiers, or other water management systems in place? If you get vague or evasive answers, consider it a red flag. 4. Building Materials: Mold Food vs. Mold Fighters Mold needs three things to thrive: moisture, warmth, and food. The “food” in this case is often the building material itself. Here’s what to watch for: 🧫 Common Mold Food Materials: Drywall (especially the paper backing) OSB (oriented strand board)—commonly used in subfloors and walls MDF (medium-density fiberboard)—found in cheap cabinetry and furniture Carpet and padding—traps moisture and dust Wood framing—especially untreated lumber in humid climates 🛡 More Mold-Resistant Materials: Cement board (great for bathrooms and basements) Metal framing Tile or stone floors Closed-cell spray foam insulation Mold-resistant drywall (often purple or green board) While no material is completely mold-proof, choosing ones that don’t feed mold can significantly reduce your risk. 5. Use an ERMI Test: DNA-Based Mold Detection The Environmental Relative Moldiness Index (ERMI) test is a scientific way to assess mold levels. You collect dust from different areas of the home, and a lab analyzes it for mold DNA. The results come back with a score based on the types and quantities of mold detected. Have a professional help you interpret the ERMI, don’t look at the score. Keep in mind: ERMI doesn’t tell you where the mold is—it just tells you if it’s there. But it’s a great tool for screening. 6. Hire an IEP: Your Environmental Detective An Indoor Environmental Professional (IEP) is specially trained to find hidden mold issues. They use tools like: Infrared cameras Moisture meters Particle counters Borescopes (to look inside walls) A good IEP will also evaluate the HVAC system, attic, crawlspaces, and any signs of past or current water intrusion. They’ll give you a full report and let you know if the home is safe—or not. Tip: Make sure your IEP is mold-literate and familiar with patients who have chronic illness or environmental sensitivities. 7. Don’t Forget the HVAC System The HVAC system can either be your best friend—or your worst enemy. If contaminated, it will distribute mold and mycotoxins into every room of the house. Make sure to ask: Has it been professionally cleaned? Are the coils and pans mold-free? Are HEPA filters or UV systems in place? Are the ducts sealed and insulated? Your IEP should inspect the system thoroughly as part of their evaluation. Final Thoughts: Be Your Own Advocate Finding a truly safe home isn’t always easy—but it is possible. Trust your instincts. Ask the hard questions. And don’t let a pretty exterior fool you—mold often hides in the places you can’t see. As a medical detective, I believe healing starts at home. So arm yourself with knowledge, tools, and expert support—and you’ll find the safe haven your body needs.

How to Find a Healthy (Mold-Free) Home When You’re Mold-Sensitive

Dr. Fox Medical Detective Blogs
June 11, 2025•4 min read

For people living with mold illness, finding a safe home is not just about comfort—it’s about survival. I’ve seen too many patients worsen after moving into a “clean” house that turned out to be a mold minefield. Whether you’re buying or renting, you must become a mold detective to avoid a hidden health hazard.

In this guide, I’ll walk you through how to assess a home for water damage, what to ask about its history, the tools you can use (like ERMI testing and hiring an IEP), and why even brand-new homes can be risky. Let’s get started.

1. New Doesn’t Mean Safe: The Myth of the Modern Home

It’s tempting to believe that a newer home equals a healthier home—but that’s not always the case.

In fact, many newer homes are built too tightly sealed, which means there’s poor air exchange. Without proper ventilation, humidity builds up—creating the perfect environment for mold to grow inside walls, HVAC systems, or even under flooring.

Even more concerning: the wood used to frame new homes often sits out in the rain or snow for weeks—or even months—during construction. This untreated lumber can absorb moisture, and if it’s enclosed in drywall before fully drying, it becomes the perfect hidden breeding ground for mold.

While the home might look pristine at closing, you could be walking into a structure already contaminated from the inside out.

Add to that the fact that many newer homes rely on cheaper, mold-prone materials like OSB (oriented strand board) and paper-backed drywall, and it’s easy to see why new construction isn’t necessarily safer for mold-sensitive individuals.

2. Know the Signs: What to Look For During a Walkthrough

Before you bring in professionals, do your own detective work. Keep an eye out for:

  • Water stains or discoloration on ceilings and walls

  • Musty or earthy smells, especially near bathrooms, basements, and HVAC vents

  • Buckling floors or baseboards, which may indicate past water intrusion

  • Peeling paint or bubbling drywall

  • Visible mold—even a tiny patch can indicate a larger problem

  • Humidity levels—use a hygrometer to make sure levels stay under 50%

inspecting a home with a moisture meter, emphasizing the importance of checking for mold when searching for a healthy living space.

3. Ask the Big Questions: Uncover the Home’s Water History

A clean-looking house may still have a dirty past. Always ask:

  • Has the home ever experienced flooding, leaks, or plumbing issues?

  • Were any insurance claims filed related to water damage?

  • Were remediation efforts documented and professionally completed?

  • How old is the roof, HVAC, and plumbing system?

  • Are there sump pumps, dehumidifiers, or other water management systems in place?

If you get vague or evasive answers, consider it a red flag.

inspecting a home with a moisture meter, emphasizing the importance of checking for mold when searching for a healthy living space.

4. Building Materials: Mold Food vs. Mold Fighters

Mold needs three things to thrive: moisture, warmth, and food. The “food” in this case is often the building material itself. Here’s what to watch for:

Common Mold Food Materials:

  • Drywall (especially the paper backing)

  • OSB (oriented strand board)—commonly used in subfloors and walls

  • MDF (medium-density fiberboard)—found in cheap cabinetry and furniture

  • Carpet and padding—traps moisture and dust

  • Wood framing—especially untreated lumber in humid climates

More Mold-Resistant Materials:

  • Cement board (great for bathrooms and basements)

  • Metal framing

  • Tile or stone floors

  • Closed-cell spray foam insulation

  • Mold-resistant drywall (often purple or green board)

While no material is completely mold-proof, choosing ones that don’t feed mold can significantly reduce your risk.

5. Use an ERMI Test: DNA-Based Mold Detection

The Environmental Relative Moldiness Index (ERMI) test is a scientific way to assess mold levels. You collect dust from different areas of the home, and a lab analyzes it for mold DNA. The results come back with a score based on the types and quantities of mold detected. Have a professional help you interpret the ERMI, don’t look at the score.

Keep in mind: ERMI doesn’t tell you where the mold is—it just tells you if it’s there. But it’s a great tool for screening.

6. Hire an IEP: Your Environmental Detective

An Indoor Environmental Professional (IEP) is specially trained to find hidden mold issues. They use tools like:

  • Infrared cameras

  • Moisture meters

  • Particle counters

  • Borescopes (to look inside walls)

inspecting a home with a moisture meter, emphasizing the importance of checking for mold when searching for a healthy living space.

A good IEP will also evaluate the HVAC system, attic, crawlspaces, and any signs of past or current water intrusion. They’ll give you a full report and let you know if the home is safe—or not.

Tip: Make sure your IEP is mold-literate and familiar with patients who have chronic illness or environmental sensitivities.

7. Don’t Forget the HVAC System

inspecting a home with a moisture meter, emphasizing the importance of checking for mold when searching for a healthy living space.

The HVAC system can either be your best friend—or your worst enemy. If contaminated, it will distribute mold and mycotoxins into every room of the house. Make sure to ask:

  • Has it been professionally cleaned?

  • Are the coils and pans mold-free?

  • Are HEPA filters or UV systems in place?

  • Are the ducts sealed and insulated?

Your IEP should inspect the system thoroughly as part of their evaluation.

Final Thoughts: Be Your Own Advocate

Finding a truly safe home isn’t always easy—but it is possible. Trust your instincts. Ask the hard questions. And don’t let a pretty exterior fool you—mold often hides in the places you can’t see.

As a medical detective, I believe healing starts at home. So arm yourself with knowledge, tools, and expert support—and you’ll find the safe haven your body needs.

mold in new constructionwater-damaged home signsERMI test for moldmold-resistant building materialsHVAC mold inspection
Back to Blog