Mold growth on drywall can be a concerning sight for any homeowner. You may wonder if you need to replace affected drywall or if you can clean and salvage it. The answer depends on several factors.
What causes mold on drywall?
Mold spores are present in virtually all environments. When spores land on a damp surface, they can begin growing mold colonies. The most common causes of mold on drywall include:
- Water damage from leaks, floods, or excessive humidity
- Condensation building up on cold surfaces in the home
- High indoor humidity from lack of ventilation
Drywall is made of paper and gypsum. With the right moisture levels, it can be an ideal environment for mold. Any water intrusion, leak, or condensation issue should be fixed to prevent mold from recurring after remediation.
Can you clean mold off drywall?
In some minor cases, mold on drywall may be cleaned without replacement. To determine if cleaning is possible:
- Assess the extent of mold – small areas of surface mold may be cleanable
- Test if it is surface mold only or has spread into drywall
- Identify the type of mold – some types like Stachybotrys are highly toxic
The EPA and most experts recommend cleaning for small mold patches less than 10 square feet. Larger infestations or toxic mold usually require replacing sections of drywall.
Cleaning methods
To try removing mold from drywall:
- Protect yourself by wearing gloves, goggles and an N95 mask
- Cordon off the area from the rest of the home
- Remove any items/furniture from the area
- Scrub drywall with mild detergent and water using a stiff brush
- Use a separate brush to clean cracks and crevices
- Rinse thoroughly and dry immediately with fans
- Apply a disinfectant or mold killer
- Seal treated areas with primer and paint
Vinegar, hydrogen peroxide, baking soda, and ammonia are common household mold cleaners. Bleach is not recommended as it only removes surface mold, while peroxide can help penetrate and kill interior mold.
When does drywall need replacement?
In many cases, moldy drywall cannot be adequately cleaned and needs replacement. Typical situations requiring drywall removal include:
- Visible mold covering over 10 square feet
- Signs the mold has spread into drywall such as a dark pattern under the surface
- Affected by toxic black mold species
- Evidence of decay, soft spots, or drywall paper separating
- Previously been painted over to hide mold
- Water damage warping or delaminating drywall
Trying to clean large areas of contaminated drywall is not worth the effort and risks leaving behind mold. It is safer and more effective to cut away affected drywall and replace it.
Remediation process
Full mold remediation involves:
- Protecting the area from the rest of the home
- Removing personal items and furniture
- Taking safety precautions with PPE
- Cutting and removing visibly moldy drywall plus some extra beyond
- Disposing of moldy drywall properly
- Treating wood studs behind drywall with borates
- Replacing with new drywall
- Mud, tape, prime and paint new drywall
- Thoroughly cleaning the area of any residue
- Addressing moisture source and enhancing ventilation
Replacing just a small section of drywall can lead to more recurring mold. It is best to remove and replace full sheets from stud to stud.
Health risks of moldy drywall
Extensive mold contamination creates potential health risks including:
- Allergic reactions – runny nose, watery eyes, coughing, wheezing
- Asthma attacks in those with sensitivities
- Respiratory problems from mold spores
- Fungal infections in those with compromised immunity
- Toxic reactions from mycotoxins that some molds release
Infants, young children, the elderly and those with chronic illnesses are most vulnerable to mold’s effects. Even small areas of Stachybotrys chartarum or black mold should be promptly removed due to toxicity concerns.
DIY or professional remediation?
You may be tempted to tackle a small drywall mold problem yourself through cleaning or replacing just a section. However, there are benefits to having a professional mold remediation company handle it:
- Proper containment and negative air pressure to prevent spore spread
- Industrial HEPA vacuums to thoroughly clean contamination
- Testing to identify specific mold types present
- Access to alternate drywall repair methods like mold resistant drywall
- Training and equipment to safely remove and dispose of mold
- Assessing moisture problems and secondary damage
- Follow up testing after remediation to confirm mold levels are safe
Professional remediation can cost $500 to $5000 depending on size. The investment helps ensure mold and health hazards are fully eliminated.
Preventing mold on drywall
To help avoid needing mold remediation:
- Maintain indoor humidity under 50%
- Ventilate bathrooms, kitchens and laundry rooms
- Insulate exterior walls to prevent condensation
- Promptly repair any water leaks or damage
- Clean up spills and overflows right away
- Regularly clean and disinfect humidifiers
- Install exhaust fans to manage moisture
Monitor your home for excess moisture and condensation. Fix dripping faucets, clear HVAC drip pans outside, and seal openings where humidity can enter. With vigilance, you can avoid creating an environment conducive to mold.
Conclusion
Small surface mold spots on drywall less than 10 square feet may be cleanable in some cases. However, large colonies, interior mold or toxic species will require cutting out and replacing sections of drywall. Professional mold remediation is the safest solution to eliminate health hazards from contaminated drywall in most cases. With preventative moisture control, you can help keep your home free of mold.