Mold is gnarly: you can’t just clean it, you have to kill it.
That’s because mold is a living microorganism, similar to yeast or mushrooms. With a little moisture, mold can grow on pretty much any surface, and once it starts growing, tiny, hair-like roots and floating spores help it spread. If mold gets into the wood frame of a home, it can actually impact the structural integrity. It also smells.
Like we said, it’s gnarly.
The best way to clean mold depends on where it’s growing. Cleaning mold on nonporous surfaces, like glass or tile, is usually pretty straightforward. But when mold grows on porous surfaces, like wood, drywall, or grout, getting rid of it is more difficult, since the roots of the mold can burrow deep into the material.
Before You Get Started
There are a few things you should know about cleaning mold. First, if the mold problem is severe (if it covers an area larger than 10 square feet), it’s probably in your best interest to reach out to a professional mold removal service. Second, if you don’t address the underlying issue causing mold (moisture!), it doesn’t matter how well you clean, the mold is just going to grow back. Lastly, a word about bleach. Chlorine bleach is the go-to mold cleaning product in many households. But the truth is, bleach is only effective on nonporous surfaces (more on this later).
Cleaning Mold on Glass, Tile, and Other Nonporous Surfaces
Step 1: Gear up!
Even if you’re just cleaning a small amount of mold, you’ll want to wear protective gear. The Environmental Protection Agency (EPA) recommends wearing rubber gloves that extend up the forearm, goggles without ventilation holes, and a face mask. Once you start cleaning, mold spores will be flying through the air like tiny dandelion seeds. Wearing all this gear may make you feel like a mad scientist, but if mold spores get into your system, they can cause health problems — especially if you have asthma or other respiratory issues.
Your face mask should be rated N-95 or higher. Face mask ratings are based on the size and types of particles they filter. An N-95 rated mask removes 95 percent of all particles that are at least 0.3 microns in diameter, which is good enough to filter mold spores.
Step 2: Select a cleaner or DIY one
There are several commercial-grade cleaning products to help you clean mold. But you also have a lot of options if you prefer to go a more eco-friendly, do-it-yourself route.
Commercial cleaners: If you want to go with a store-bought cleaner, try one of these options:
Liquid cleaners: These are dozens of effective liquid products, like Tilex Mold and Mildew Remover. They typically come in spray bottles or gallon jugs and tend to have more chemicals than other options, but they’re still completely safe to use if you follow the instructions.
Borax: Borax is a natural cleaner that doesn’t emit chemicals or fumes (though it is toxic if swallowed). To make a mold cleaner, mix 1 cup of Borax for every gallon of water.
Laundry detergent: Mix a scoop of laundry detergent with a half gallon of warm water.
Ammonia: Create a solution that is 50 percent water and 50 percent clear ammonia.
Never mix ammonia with bleach — you’ll create a mixture that emits a toxic gas. Commercial cleaners and detergents can contain either ingredient, so read labels carefully before mixing products. (In fact, mixing multiple cleaning products is generally not a good idea.)
DIY | Eco-Friendly
Hydrogen peroxide is antifungal, antiviral, and antibacterial, and can be used to kill mold. It’s safe to use on all types of surfaces, but it is a bleaching agent, so you should test it on a small, relatively discrete area before cleaning on. All you’ll need is some 3 percent concentration hydrogen peroxide and a spray bottle.
Vinegar can be used to kill mold, too. A spray bottle with 1 part distilled white vinegar and 9 parts water and you should be effective on the vast majority of mold species.
Baking soda is another natural, safe, all-star cleaner that works on mold. Add ¼ tablespoon of baking soda to a standard 16 oz. spray bottle of water, shake things up until the baking soda dissolves, and you’re good to go. Baking soda comes with the added bonus of being a deodorizer, which can help get rid of any mold odor.
Tea tree oil is antifungal and antibacterial, and is capable of killing all types of mold. It’s more expensive than the other DIY options, but it’s also the most effective. Mix 1 teaspoon of tea tree oil with 1 cup of water.
Grapefruit seed extract is similar to tea tree oil: it’s slightly more expensive and very effective at killing mold. This natural cleaning remedy is almost odorless, and potent — you’ll only need 10 drops of grapefruit seed extract for every 1 cup of water.
Step 3: Spray (and wait)
Use a spray bottle to apply the commercial or DIY cleaner of your choice. Don’t be shy, go ahead and give that mold a good dousing. If you’re using a cleaner that kills mold, you’ll want to wait at least 10 minutes for the cleaner to soak in before you start scrubbing. This allows the cleaner to seep into the roots and ensure the mold is killed.
Step 4: Scrub
This is where a good pair of gloves and a face mask are important. Grab a sponge or firm-bristled brush and start scrubbing. If you’re scrubbing mold from tile or glass, the mold should wipe off without much effort. If you’re cleaning mold from a tiled surface, be aware that grout is porous and mold roots can dig deep — you’re in for a more intense scrubbing session. Apply plenty of cleaner along the grout lines and allow it to soak before you scrub.
Seal any doorways or other openings. Mold spores are tiny, and just like dandelion seeds, they’re flying through the air looking for a new home. If possible, seal off any doorways or other openings that lead to other areas of your home. That will help ensure the flying spores don’t set up shop in a new location.
Step 5: Spray round II (optional)
In some cases, you might see some lingering mold stains after the initial scrub. If that’s the case, you’ll need to hit the mold with another round of spraying and scrubbing. (Remember to let the the cleaner soak for at least 10 minutes before you start scrubbing.)
Even if you don’t see mold stains, applying a second (or third) round of mold-killer can help ensure you get to the roots. Spray another generous layer of cleaner on the targeted area, and let it sit for up to an hour.
Step 6: Rinse and dry the area
After you’ve scrubbed the mold away and applied a second round of cleaner, rinse the area and use a towel or paper towel to pat the area dry. If the mold resurfaces, continue to treat the area on a weekly basis. If you’re not having success with one cleaner, swap it out for a different one. But remember, mold loves moisture. If you’re not addressing the moisture problem, mold is going to keep growing back.
Cleaning Mold on Wood, Drywall, Carpet, and Other Porous Surfaces
Getting rid of mold on porous surfaces can be considerably more difficult — especially if the mold roots have had time to burrow deep into the material. If you catch it early, there’s still hope that you won’t have to scrap everything and start from scratch.
You might need:
A vacuum with a HEPA filter
Step 1: Gear up!
Before you start cleaning, get a good pair of rubber gloves, non-ventilated goggles, and a face mask rated N-95 or higher. If you’re cleaning a large area with a lot of mold, you might even consider a disposable hazmat suit (don’t worry, they’re cheap — usually less than $10). All this gear may seem a little intense, but it’s all in the name of healthy and safety. You don’t want mold spores in your system, and wearing the right gear will help keep it out.
Step 2: Bust out the vacuum
Vacuum the wood, drywall, or carpeted area using a vacuum with a HEPA filter. This will help get rid of any loose mold spores and other debris.
After you vacuum, dump the contents of the vacuum bag into a plastic bag. Seal that bag up and toss it in a garbage can outside your home. That way you won’t inadvertently spread mold spores if you use the vacuum in other areas of the house.
Step 3: Spray, wait, and scrub
Each of the commercial and DIY cleaners mentioned in the previous section can also be used on wood, drywall, carpet, or other porous surfaces. With porous surfaces, it’s best to use a cleaner that actually kills the mold (as opposed to those that just help clean the surface).
Apply the cleaner to the mold, wait for at least ten minutes to let the cleaner soak in, and then grab a sponge or firm-bristled brush and start scrubbing.
Step 4: Wipe and dry
Wipe the area with a damp cloth. If you still see mold, go through the spray-and-scrub process a second time. Then take a damp cloth to wipe the area clean, followed by a dry cloth to suck up any remaining moisture.
Bonus Steps for Wood and Drywall
If you’ve gone through the cleaning process and still see mold, you can use a vacuum-sander to sand the mold (and mold roots) away. You can then apply a clear wood finish to help protect the area against moisture and future mold growth.
Bleach Won’t Kill Mold
As alluded to earlier, chlorine bleach is often the first product people reach for when cleaning mold. But both the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) advise against it.
The use of a biocide, such as chlorine bleach, is not recommended as a routine practice during mold remediation.
Occupational Safety and Health Administration (OSHA)
As noted by the EPA, “In most cases, it is not possible or desirable to sterilize an area; background level of mold spores will remain.” In other words, when you use bleach to clean mold, you’re leaving spores behind. The surface may look clean, but mold roots are lurking below the surface and if you don’t address the moisture problem, the spores will just grow back.
The only instance where you might consider using bleach in the mold-cleaning process, is when you’re trying to remove discoloration from hard, non-porous surfaces. For example, you might use bleach to try to remove mold stains from tile or glass. Otherwise, it’s best to follow the expert advice and skip the bleach altogether.
How to Prevent Mold
By now it should be pretty clear that addressing the source of moisture is the key to getting rid of mold for good. Here’s how:
Identify problem areas. Perform a monthly walk-through of your home and look for common signs of mold, such as discoloration, odor, peeling paint, or condensation. If you see (or smell) a potential problem, look for the source of moisture and take steps to get it under control.
Ventilate. Routine activities in the bathroom, kitchen, and laundry room can encourage mold growth. Use the ventilator in your bathroom whenever you shower or bathe, and the fan above the stove whenever you cook. If that’s not enough, crack a window or door to allow the humid air to escape.
Dry wet areas immediately. Wipe down every-day spills or unexpected leaks as soon as possible. Use a squeegee, towel, or sponge to wipe down the shower walls after each shower. It may feel a bit excessive, but getting rid of that water can go a long way in reducing mold in the bathroom.
Use a mold-resistant drywall and paint. Mold-resistant drywall is covered with fiberglass (instead of paper, like traditional drywall), which makes it incredibly water resistant. If replacing the drywall isn’t an option, consider using mold-resistant paint, which contains a mildewcide designed to inhibit mold growth.
Use a dehumidifier in problem areas. Windowless bathrooms, humid basements, poorly ventilated kitchens, and other similar scenarios can be a nightmare for humidity control. Running a dehumidifier can help control moisture and prevent mold growth.
Skip the mold-sampling. Some professional mold removal services might encourage you to pay to sample and test your mold. The purpose of the sample is to determine if the mold is harmful, but as pointed out by the EPA, in most cases, if visible mold growth is present, sampling is unnecessary. Skip the sample, and just get to the part where you get rid of it.
Step 1: Get your hands on a good pair of gloves, goggles, and N-95 face mask.
Step 2: For wood, drywall, and other porous materials, suck up those pesky mold spores and any other loose debris with a vacuum (then empty the bag).
Step 3: Spray the mold with the cleaner or DIY mold solution of your choice (not bleach). Be patient. Let the spray sit for at least ten minutes.
Step 4: Scrub and wipe until the targeted area is clean.
Step 5: Rinse the area and pat dry.
Step 6: Take steps to solve your moisture problem for good, so the mold won’t grow back.