A Musty Smell but No Visible Mold: Could It Be Hidden Mold?

Mold you can see is a different problem from mold you only suspect. A smell can be the first and only sign.

EPA says you may suspect hidden mold if a building smells moldy but you cannot see the source. It can be behind drywall, wallpaper or paneling, in wall cavities, or in ductwork (EPA).

Mold needs moisture. EPA puts it this way: the key to mold control is moisture control. So the practical search is for water, not for mold.

• A past or present leak. EPA says to repair plumbing leaks and other water problems as soon as you find them, and to dry wet or damp items and areas within 24 to 48 hours (EPA).
• Condensation. EPA says condensation on windows, pipes or walls can be a sign of high humidity. Dry the surface quickly and reduce the source of moisture (EPA).
• Humidity. EPA suggests keeping indoor humidity below 60 percent, ideally between 30 and 50 percent, and says an inexpensive humidity meter from a hardware store can measure it (EPA).
• Air conditioner drip pans and drain lines. EPA says to keep drip pans clean and drain lines unobstructed so water flows properly (EPA).

If the moisture came from a leak, a burst pipe or a flood, the drying has to be done properly. See structural drying and water damage restoration.

EPA warns that investigating hidden mold problems can be difficult and calls for caution, because disturbing hidden mold can release spores. If you believe you have a hidden mold problem, EPA says to consider hiring an experienced professional (EPA).

EPA says that in most cases, when mold growth is visible, sampling is unnecessary. It also says EPA has set no federal limits for mold, so sampling cannot be used to check a building’s compliance with federal mold standards, and that sampling should be done by professionals with experience in designing a sampling plan and interpreting the results (EPA).

That is EPA’s general guidance. It is not a description of how H&H carries out an assessment.

If anyone in your household has asthma, allergies or other health concerns, talk with a healthcare professional. EPA says people with asthma should avoid contact with mold, and recommends consulting a health professional, your state or local health department, or the CDC for more detailed information (EPA). See also what EPA says about mold and health.

H&H Environmental has operated since 2005 and offers both mold assessment and mold remediation. A mold assessment is an evaluation of whether there is mold, and where.

On a New York mold project, H&H performs either the mold assessment or the mold remediation — never both on the same project. See mold assessment, mold remediation and mold services.

H&H is based in Saugerties, in Ulster County, and focuses on eight New York counties. Call and tell us where the property is and what you have noticed, and we will confirm availability.