Mix one cup of bleach to 1 gallon of water. It can then be sprayed onto the concrete and scrubbed. Most of the mold should be removed through this method. A less aggressive method is to mix 1 cup of vinegar with 2/3 cups of water in a spray bottle.
Vinegar is a natural and safe alternative to cleaning concrete with harsh chemicals. In the case of algae and mold, it does a better job than bleach, and it is better in the long term for killing these infestations. Oftentimes, vinegar can be found in your home or garage.
Vinegar Solution
Vinegar is the perfect option in such cases. Used similarly to bleach, vinegar is known to kill many species of fungus including harmful mold. Spraying a vinegar solution (1 cup of vinegar per gallon of water) onto the surface, saturating it fully, should kill most strains of mold.
Vinegar is an all-natural solution for cleaning concrete. It kills mildew and mold, removes grime, and helps treat set-in stains. Before cleaning concrete with vinegar, it's essential to dilute it so you don't affect your sealer. Here's what type of concrete to clean with vinegar and which types to avoid.
A bleach solution also works to kill mold. Mix one cup of bleach in a gallon of water, apply to the surface and don't rinse. Mix a 50/50 solution of ammonia and water. Spray on the surface, wait two to three hours, then rinse.
As a gentler cleaner, bleach can't harm concrete's durable material. Aside from being an effective cleaner and stain remover, it also acts as a disinfectant to the concrete surface.
Molds are fungi and they can, and will, grow back after bleaching. There are 4 simple ingredients you can safely use to clean away mold in your home: white vinegar, baking soda, hydrogen peroxide, and detergent or soap.
Pour enough undiluted white vinegar into the empty spray bottle to cover the area of mold growth. Spray the mold directly, fully saturating it with the vinegar, and allow the vinegar to sit for at least an hour. Don't be tempted to scrub or rinse; the mold needs time to completely absorb the vinegar.
It should be noted that vinegar cannot kill every type of mold, according to a study from 2015. It is highly effective at getting rid of Penicillium chrysogenum, which is most commonly found in damp areas, but not Aspergillus fumigatus, which is typically found in plant matter and soil.
Alkaline cleaners are great for lifting oil stains, grease stains, and other petroleum-based stains from concrete. It's an added benefit that you can use it with a pressure washer, making the job that much easier. For an eco-friendly cleaner, we recommend Oil Eater cleaner degreaser (US$15.74, Amazon).
Mold professionals use expensive, professional equipment such as HEPA (High Efficiency Particulate Air) air scrubbers, HEPA vacuums, commercial-strength dehumidifiers, etc. Regular handymen won't have that stuff.
Mold generally looks slimy or fuzzy, tends to have a raised texture, and can come in a rainbow of colors, including deep green and black. Mildew is powdery, looks white or gray, always appears flat, and grows on surfaces.
White vinegar will not damage your concrete. However, leaving this solution for an extended period will damage the cement that binds the concrete together. Hence, you should be careful when using vinegar on your concrete, especially if you will use this solution on polished concrete.
Mix 1 cup each of vinegar and warm water into a spray bottle. Spray a cleaning cloth with the solution and gently dab the affected area until the mould is gone. Absorb the cleaning solution with a dry cloth and leave to air dry.
For a diluted bleach solution, mix three parts water with one part bleach in a bucket. You can also use white vinegar to kill mold. Don't forget to test a small, discreet area first. Bleach and other chemicals can discolor concrete that's been colored or stained.
Vinegar successfully kills mold on drywall and leather.
This means that the mold is likely to grow back. When bleach is used on porous surfaces, the mold will move deeper into the material to avoid it.
So you can see why allowing the vinegar to sit for sometime is beneficial, but for too long and you're only wasting time because the vinegar will dry out eventually and become less effective. Also, you risk causing damage to the area beneath the mold when you leave the vinegar to sit on it for too long.
If you don't already have some at home, white vinegar can be inexpensively purchased at most grocery stores. Vinegar can be used to kill mold on both nonporous surfaces and porous surfaces. Compared to bleach, it can more easily penetrate porous materials like wood to kill mold growing underneath the surface.
To clean mold, use regular white distilled vinegar, typically sold with 5% acidity. You can also use “cleaning vinegar” with 6% acidity. Both are effective at killing mold.
Borax solutions are excellent for removing mold on walls, tiles, or around plumbing. Here's what to do: Combine one cup of borax with one gallon of warm water. Add several tablespoons of soap, vinegar, or baking soda when targeting more difficult areas.
Hydrogen peroxide kills mold effectively on materials such as clothing, floors, bathroom fixtures, walls and items such as kitchen appliances. Pour 3% concentration hydrogen peroxide into a spray bottle. Spray the moldy surface completely to saturate the area with hydrogen peroxide.
Bleach quickly dries off on the surface and will not reach into the deeper part of the material to the mold's root. So, in a few days or weeks, the mold regains its color and grows back to become even worse than it was before you applied the bleach.
If you're not wearing any Personal Protective Equipment (PPE), you're inviting all of those mold spores to settle on your clothing, the area you're cleaning, your shoes (allowing mold to travel to other areas in your home), in your eyes, and up your nose into your upper respiratory system.