The short answer
How Mold and Mildew Develop
When drywall stays damp for more than 24 to 48 hours, mold spores present in all homes can begin to grow. Mold consumes the paper facing and the organic material in the drywall. This biological activity produces microbial volatile organic compounds, which are the source of that distinct, unpleasant musty or earthy odor.
The smell intensifies as the colony expands. It often becomes noticeable before any visible staining or warping appears on the drywall surface. Pay attention to seasonal changes; trapped moisture from a wet season can lead to mold odors when temperatures rise and humidity shifts.
The Risks of Ignoring the Odor
Ignoring the smell allows the water damage to worsen. The structural integrity of the drywall and potentially the wooden studs behind it can be compromised. Wet framing lumber can rot, and metal fasteners can corrode. This creates a more extensive and expensive repair project later.
Persistent moisture and mold growth also affect indoor air quality. Air movement through wall cavities can carry mold spores and odors into your living space. This may cause allergy-like symptoms or respiratory irritation for sensitive individuals.
Steps for Investigating the Source
Start by checking for obvious signs. Feel the baseboard and the drywall above it for coolness or softness. Look for subtle discoloration, bubbling paint, or a slightly warped baseboard. Use your nose to try to pinpoint the strongest area of the smell, as this can guide your search.
Inspect areas directly above and adjacent to the smelly baseboard. Check under sinks, around toilets, and near appliances for any signs of moisture. Be aware that water can travel far from the original leak, so the source might be in a different wall or even a floor below.
- Turn off all water-using appliances and check your water meter for movement.
- Use a moisture meter on the drywall surface to detect hidden dampness.
- Look in the basement or crawlspace below the affected wall for drips or stains.
- Monitor the area after heavy water use, like showers or laundry.
- Check outside for overgrown vegetation or soil touching the siding.
- Review recent utility bills for unexplained increases in water usage.
When to Contact a Water Damage Professional
If you confirm or strongly suspect moisture, it is time to contact local water damage pros. They have specialized tools like infrared cameras and deep-penetration moisture meters to map the full extent of the water intrusion without unnecessary demolition. They can find the exact leak source and assess the damage.
The pros can then outline a drying and repair plan. This often involves controlled removal of the damaged drywall to allow the wall cavity to dry properly. They can also identify if mold remediation is needed by a qualified mold professional. Policies vary, and your insurer decides what is covered.
Water damage does not wait
Every hour counts once water gets into floors and walls. One call starts the response.
Call Now (208) 537-2633Frequently asked questions
Can I just paint over the smelly drywall?
No, painting seals in the moisture and odor, making the problem worse. The water damage and any mold will continue to spread behind the paint. The affected drywall must be dried properly or replaced to solve the smell permanently.
Will my homeowner's insurance cover this repair?
It might, if the leak is sudden and accidental, like a burst pipe. Slow, long-term leaks are often excluded. Policies vary, and your insurer decides what is covered. Document the damage and contact your insurance company to start a claim.
How do I know if there is mold behind the drywall?
A persistent musty smell is a strong indicator. Visible signs include discolored patches, bulging, or soft, crumbly drywall. Local water damage pros or a mold inspector can perform an assessment with tools to detect mold without fully opening the wall.