Signs you may have a mold problem
- A musty, earthy smell, especially in basements, crawlspaces, closets, bathrooms and under sinks.
- Visible growth in black, green, white or other colors on walls, ceilings, grout, window frames or stored items.
- Water stains, peeling paint, bubbling drywall or warped flooring, which point to moisture that mold can use.
- Condensation that forms regularly on windows, pipes or walls.
- A history of leaks or flooding that wasn't dried quickly.
- Allergy-like symptoms that seem worse at home. Mold exposure can affect people differently, and people with asthma, allergies or weakened immune systems can be more sensitive. If you have health concerns, talk to a medical professional.
What an inspection should cover
A useful mold inspection is really a moisture investigation. The inspector should:
1. Ask about the history of the house: leaks, floods, repairs and where you've noticed smells or growth. 2. Look visually through living areas, attic, crawlspace or basement, around plumbing, windows, roof penetrations and HVAC equipment. 3. Use moisture meters to find damp materials, and often a thermal imaging camera to spot cool, damp areas behind surfaces. 4. Measure indoor humidity. 5. Identify the moisture sources and the extent of growth. 6. Provide a written report with photos, the locations of mold and moisture, and recommendations.
Is testing necessary?
Sampling isn't always needed. If mold is visible, the priority is usually to fix the moisture and remove the mold, regardless of species. Testing can help in specific situations: to look for hidden growth when there's a smell but nothing is visible, to check whether cleanup worked (clearance testing), or when required for a real estate transaction or by a landlord. Air samples are a snapshot and can vary widely with conditions. Ask the inspector what question the testing will answer and how the results will change the recommendations.
Independent inspection
Some homeowners prefer an inspector who doesn't also sell remediation, so the assessment isn't influenced by the repair job. That's especially useful for clearance testing after remediation. Ask whether the inspector also does removal work.
Reading the report
A good report tells you where the moisture is coming from, how much material is affected, what should be removed or cleaned, and what needs to be fixed to stop the moisture. It should be specific: "a slow leak at the shower valve has wet the wall cavity on the bedroom side; drywall and insulation in that area are affected," not just "mold detected."
Questions to ask
- What's the moisture source, and how did you find it?
- How large an area is affected?
- Do you recommend testing, and what will it tell us?
- Do you also perform remediation?
- Will I get a written report with photos?
Before buying a home
If you're buying a house with signs of past water damage, a musty smell, or a basement or crawlspace that has flooded, a mold and moisture inspection before closing can reveal problems a general home inspection may only note in passing. Ask the inspector to focus on the areas the home inspector flagged.
Renters
If you rent and see mold or smell mustiness, tell your landlord in writing and keep a copy. Moisture sources such as plumbing and roof leaks are usually the owner's responsibility to fix.