Mold growing in the spaces between walls is a common problem in many homes. This type of mold is often referred to as hidden mold or concealed mold. It can be challenging to detect and even more difficult to remove. If left unchecked, hidden mold can cause serious health issues, structural damage and reduced indoor air quality.
The good news is that with persistence and the right techniques, you can eliminate mold between walls and prevent its return. This article provides a step-by-step guide on how to identify, treat and prevent concealed mold between walls.
How Does Mold Get Between Walls?
Mold spores are present in virtually all indoor and outdoor air. When excess moisture gets inside walls, it creates an ideal environment for mold growth. There are a few common ways this can occur:
- Plumbing leaks – Leaky pipes or overflowing sinks/tubs can soak wall cavities and sheathing.
- Roof leaks – Damage to roof coverings can lead to water intrusion and moisture buildup between walls.
- Flooding – Major flooding events can saturate wall cavities with water.
- Condensation – Temperature differences between wall cavities and living spaces can lead to condensation buildup inside walls.
- Ground moisture – Capillary action can wick ground moisture up into wall materials.
Once mold spores come in contact with damp wall cavities, they germinate and quickly multiply. Even small amounts of moisture are enough to sustain mold growth.
Signs of Mold Between Walls
Detecting the presence of concealed mold can be tricky. Here are some common signs that may indicate hidden mold growth between walls:
- Musty odor – A persistent musty, earthy smell may point to mold growth within walls.
- Peeling paint or plaster – As mold spreads beneath surfaces, it can cause paint or plaster to crack and peel away.
- Dark spots – Mold may cause dark spots or staining on drywall or other materials.
- Bubbling wallpaper – Wallpaper can bubble and peel away from the wall as mold grows underneath.
- Warping boards – Mold can warp wood studs and cause wood or other materials to delaminate.
- Pests – Flies, carpet beetles and other pests may be attracted to mold growth.
If you suspect concealed mold, the first step is confirming its presence and extent. This involves a detailed inspection and may require removing wall materials.
Inspecting for Hidden Mold
Start by carefully examining all walls, corners, ceilings and floors for any visible signs of mold growth or moisture damage. Use your nose as well as your eyes to detect any musty, moldy smells.
Next, identify any potential moisture sources. Look for plumbing leaks, roof leaks, condensation issues, foundation seepage and other water intrusion points. Moisture meters and thermal imaging cameras can also help pinpoint areas of excess moisture.
To confirm the presence and extent of hidden mold, some demolition is required. One option is to partially peel back wallpaper in several spots to check underneath. Remove outlet and switch plate covers and use a borescope to look for mold within wall cavities.
The most definitive way to inspect for concealed mold is to cut exploratory holes in wall materials. Use a utility knife to penetrate the drywall paper and a keyhole saw to cut openings about one foot in diameter. Use proper protective gear when doing this to avoid exposure to mold spores.
Thoroughly inspect all exposed wall cavities for any visible mold growth or moisture damage on wood, insulation and other materials. Take photos and detailed notes on the locations and extent of any mold. Repair all exploratory holes after inspection.
Treating and Removing Mold
Before treating and removing mold, identify and fully repair all moisture sources that allowed mold to grow in the first place. Failing to address underlying moisture issues will likely result in repeat mold growth even after remediation.
Small areas of mold between walls may be treatable with household mold removal products. Mix a spray solution of dish soap, white vinegar and borax in equal amounts. Spray or foam this solution directly onto affected areas after taking safety precautions.
For more extensive mold growth, professional mold remediation is recommended. Companies use specialized tools like vacuum systems with HEPA filters to contain and remove mold. They also treat wood and other absorbent materials with antimicrobial sealants to inhibit mold.
Wall cavities and materials with severe mold contamination may need replacement. This includes removing and replacing drywall or plaster as well as affected insulation. In some cases, the wood framing itself may be too damaged and need replacement. Proper protective equipment should be used during removal work.
Preventing Future Mold Growth
The key to preventing recurring mold between walls is keeping all wall cavities consistently dry. Here are some tips:
- Address exterior moisture sources – Keep rainwater diverted away from foundations with proper grading/drainage. Maintain roof coverings to prevent interior leaks.
- Fix plumbing leaks promptly – inspect pipes and repair even minor leaks right away.
- Improve ventilation – Use exhaust fans, open windows and dehumidifiers to keep indoor humidity low.
- Insulate exterior walls – Insulation limits temperature differences that create condensation inside walls.
- Seal penetrations – Seal all wall penetrations for utilities, pipes and wires to prevent moisture entry.
Monitoring indoor humidity levels and being observant for any musty smells or moisture signs will help avoid a repeat mold problem. Consider mold testing or an annual inspection of susceptible areas like below windows.
Conclusion
Mold growing between walls is a common but serious issue for homeowners. Left unchecked, it can negatively impact indoor air quality and lead to structural decay. With diligent inspection, proper removal techniques and addressing underlying moisture sources, you can successfully eliminate hidden mold between walls. Consistent prevention steps will help keep the mold from coming back once your home is mold-free.