Wood that gets wet from leaks or other moisture sources can become a breeding ground for mold, both inside and outside. It’s important to safely remove mold from wood to avoid spreading spores that can cause allergies or breathing issues for you and your family. Black mold is particularly dangerous and should be cleaned up quickly. Here are some steps to clean moldy wood and tips to prevent it from coming back.
How Often to Clean Mold from Wood
Clean wood surfaces as soon as you spot any mold. For outdoor wood furniture, decks, and siding in humid areas, it’s best to clean them at least once a year.
What You’ll Need
Equipment / Tools:
- Long pants and long-sleeved shirt
- Protective air mask
- Rubber gloves
- Safety goggles
- HEPA filter vacuum
- Soft-bristled scrub brush
- Sponge
- Measuring cups and spoons
- Spray bottle
- Soft cloth
Materials:
- Dishwashing liquid
- Water
- Distilled white vinegar
- Wood cleaner
- Chlorine bleach
- Sandpaper (if needed)
- Wood stain, sealer, or paint (if needed)
How to Remove Mold from Wood
Put on Protective Clothing
Before handling mold, wear protective clothing such as a long-sleeved shirt and long pants, preferably old ones as bleach can permanently stain them. Also, put on a protective air mask, rubber gloves, and safety goggles. If you can, take the moldy wood outside to clean it, which helps prevent spreading spores inside. If you need to stay indoors, close doors or use plastic sheeting to protect other areas.
Vacuum the Mold From the Wood Surface
Use a vacuum with a HEPA filter to capture mold spores effectively. After vacuuming up as much mold as possible, clean the vacuum canister or remove the bag outside. Seal the vacuum bag in a plastic bag and dispose of it in the trash.
Wash Sealed or Painted Wood
If mold is on painted wood (like an interior door) or sealed wood (like flooring), start by washing the surface with a solution of liquid dishwashing detergent and water. Mix 1 tablespoon of detergent with 1 quart of water. Use a soft-bristled brush to scrub the surface gently. Avoid soaking the wood, and use a sponge to wipe away excess water as you clean.
Spritz With Distilled White Vinegar
For minor mold growth that hasn’t deeply stained or penetrated the wood, distilled white vinegar can be effective in killing the spores. Fill a spray bottle with vinegar and lightly mist the wood. Let the vinegar air-dry on the surface for at least one hour. If no stains remain, clean the wood with a quality wood cleaner, like Scott’s Liquid Gold, to condition the wood. Finally, buff the surface with a soft cloth.
Use Chlorine Bleach for Tough Mold Stains
If the mold is very severe and vinegar hasn’t removed the stains, a stronger cleaning solution is needed. This is also suitable for unsealed wood. Mix 1 tablespoon of dishwashing liquid, 1/2 cup of chlorine bleach, and 1 cup of warm water. Use a soft-bristled brush to apply the solution to the stained area. Let it air-dry. Finish by buffing the area with a soft cloth.
When using bleach, always mix it with warm water, not hot, to prevent the release of chlorine gas. Be careful to avoid inhaling any harmful fumes when working with bleach. Also, never mix bleach with products containing ammonia or vinegar.
What to Do if Mold Persists
If mold stains persist, you may need to sand the wood to remove spores that have penetrated deeply. If you’re not experienced with sanding or refinishing wood, it’s a good idea to ask for advice at a home improvement store about the right sandpaper grit for your situation. After sanding, vacuum up all the dust, and then refinish or seal the wood to help protect against future damage.
Mildew vs. Mold: What’s the Difference?
The most common type of mold in homes is mildew, which is a surface mold thriving in warm, damp areas like basements, laundry rooms, and shady porches. It starts as gray or white powder and can turn black or brown. To check if a stain on wood is mildew or just dirt, apply a dab of chlorine bleach with a cotton swab. If the stain lightens or vanishes within a few minutes, it’s mildew; if not, it’s likely dirt.
Mildew can stain and gradually damage wood surfaces. However, other molds are more harmful and can weaken your home’s structure. If you see fuzzy or slimy black or green mold, and the wood or drywall underneath feels soft or crumbles, the wood is rotting and the affected areas should be removed immediately.
What Is Black Mold?
Several molds appear black, but “black mold” usually refers to Stachybotrys chartarum, a greenish-black mold that grows on materials like wood, paper, and cotton, thriving in moist environments. This type of mold can release toxins that may cause symptoms such as coughing, wheezing, and eye irritation, with some people being more sensitive to its effects than others.
How to Prevent Mold Forming on Wood
If you experience a leak in your home, acting quickly is crucial to prevent mold growth. If you can dry the affected areas within 24 to 48 hours and fix the source of the leak, you’ll likely avoid mold development. It’s also important to quickly address any condensation on windows, pipes, or walls. Proactively manage moisture and humidity in your home: maintain your gutters and roof, ensure the ground slopes away from your foundation, check that appliances vent properly, and use exhaust fans and dehumidifiers as needed.
When to Call an Expert
If you catch mold early and it only affects a small area, you can usually remove it using household cleaners. However, for large mold problems—particularly in poorly ventilated spaces like crawlspaces—or if someone in the home has mold allergies or respiratory issues, it’s advisable to hire a professional. Experts suggest that mold covering 10 or more square feet should be professionally handled. In cases where large areas are affected, the wood may need to be replaced, and the contaminated wood should be properly disposed of. Your local public health department can provide guidance on mold testing and recommend professional mold removal services.