Phone answered 24/7 · Columbus, OH and nearby communities

Call 24/7: (614) 412-4391
Scioto River Water ResponseWater Damage Help · Columbus, OH

How Do I Know If I Have Mold Behind Drywall?

Last updated October 31, 2026

The short answer

Signs of Hidden Mold

Mold often grows unnoticed behind drywall, especially after a leak or flood. The first clue is usually a musty, earthy smell that lingers even after cleaning. You might also see discoloration on the wall surface, like brown or yellow stains, or paint that bubbles and peels.

Another sign is physical changes: drywall that feels soft, crumbles, or sags when you press on it. If you notice these, mold is likely present. Also, watch for black or green specks appearing on baseboards or around seams, which can indicate growth spreading from behind.

  • Musty or damp odor
  • Discoloration or staining on walls
  • Peeling paint or wallpaper
  • Soft or crumbly drywall
  • Visible black or green specks
  • Increased allergy symptoms at home

Using Moisture Meters

A moisture meter is a handheld tool that measures dampness in materials. You can buy one at a hardware store and press it against the drywall. Readings above 15 percent often signal a moisture problem that could support mold growth.

However, moisture meters only show surface or shallow moisture. For deeper detection, a pro might use moisture mapping, which creates a detailed picture of damp areas. If you live in Columbus, consider having a moisture mapping service done after any water event to locate hidden wet spots.

What to Do If You Suspect Mold

If you suspect mold, avoid disturbing the area. Do not poke holes or scrape the drywall, as that can release spores into the air. Keep the room ventilated by opening windows if weather allows, and reduce humidity with a dehumidifier.

Contact a local water damage pro for an inspection. They can use specialized tools to confirm mold presence and assess the extent. If mold is found, you may need drywall replacement or repair, depending on how far it has spread.

Health and Safety Precautions

Mold can trigger respiratory issues, especially in people with allergies or asthma. Symptoms like coughing, sneezing, or headaches may worsen when you are at home. If you feel unwell, see a doctor for advice. Do not try to diagnose or treat mold-related illness yourself.

When cleaning small mold spots, wear gloves, goggles, and an N95 mask. Never mix bleach with other cleaners, as that creates toxic fumes. For larger areas, leave the work to the pros, as they have proper protective equipment and containment methods.

  • Wear protective gear when cleaning
  • Keep the area ventilated
  • Avoid disturbing moldy materials
  • Seek medical help if symptoms appear
  • Do not mix cleaning chemicals

When to Call the Pros

You should call the pros if you notice mold covering more than a small patch, or if you cannot find the source of moisture. Hidden mold behind drywall often requires professional detection to locate the full extent. Water damage inspection services can identify the problem and recommend next steps.

The pros will assess the situation and may suggest drywall removal and replacement if the material is compromised. They also handle structural drying and dehumidification to prevent further growth. Remember, mold behind drywall is not something to ignore, as it can spread and cause damage over time.

Need help right now?

Call (614) 412-4391 any time, day or night, and describe what happened.

Call Now (614) 412-4391

Frequently asked questions

Can I check for mold behind drywall myself?

You can look for visible signs and use a moisture meter, but you cannot see behind the wall. For a definitive answer, a pro can use moisture mapping or take samples. If you suspect mold, it is safer to have an inspection.

Will mold behind drywall go away on its own?

No, mold will not go away without removing the moisture source and cleaning or replacing affected materials. Drying the area may stop growth, but existing mold needs to be removed. The pros can handle this safely.

Does insurance cover mold damage from a leak?

Policies vary, and your insurer decides what is covered. Some policies cover mold if it results from a sudden, accidental leak, but not from long-term humidity. Check your policy and talk to your insurance company for specifics.

Call Now (614) 412-4391