Glossary · Health & indoor air
Mold
Also called: molds · black mold
Fungi that grow on damp surfaces indoors; they can damage materials and affect health, and moisture is always the root cause.
What it means
Mold needs moisture, so it appears where there are leaks, condensation or high relative humidity: basements, bathrooms, window frames, attics and cold walls behind furniture. A musty smell can be a sign even when you can't see it. Small areas can usually be cleaned by homeowners; large or recurring growth needs a professional and a fix for the moisture source.
Why it matters in an audit
Auditors look for mold and moisture because sealing or insulating over a damp area can make it worse, so moisture problems are fixed first.
Typical numbers
Reference values with their sources. Your auditor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| Humidity to discourage mold (EPA) | Below 60%, ideally 30%–50% | epa.gov ↗ |