You can choose different cleaners to remove mold from concrete. Test on a small area to make sure the product does not cause damage. You will need protective clothing and will have to rub vigorously on the moldy areas. Then rinse the external surfaces with a pressure washer, while on the internal surfaces just wipe with a cloth. However, keep in mind that this will not prevent the mold from re-forming, so be sure to repair the water leak that is causing the problem.
Steps
Part 1 of 2: Remove the Mold
Step 1. Choose a cleaner suitable for your purpose
You can use an anti-mold cleaner, diluted bleach, or a detergent designed specifically to eliminate this type of problem. If you choose bleach, do not mix it with substances other than water, as combined with some detergents it can produce toxic fumes.
- To make a bleach solution, get a bucket and mix three parts of water with one part of bleach.
- Don't forget to carry out a preventive test on a small hidden area. Bleach and other chemicals can discolour colored or painted concrete.
Step 2. Delete the damaged objects
Any organic material adjacent to the moldy area could be contaminated. So, get rid of anything you can throw away, like cardboard boxes. Set aside items that you can move, such as furniture and rugs.
Step 3. Apply the solution
Use a sponge or sturdy brush to distribute the cleaning solution of your choice over any moldy areas of the concrete you have identified. Rub vigorously. If you are using an anti-mold product, apply it directly to the stains and scrub with a stiff bristled brush.
- Avoid the wire brush, as it can scratch the concrete.
- Wear old clothes, rubber gloves, safety glasses, and a respirator or dust mask.
Step 4. Let the solution work
If the mold stains don't go away, you may want to let the solution sit for a few minutes. After that, rub the areas you applied it to until they disappear.
Step 5. Rinse the outer concrete surface
To rinse it faster and more effectively, use a pressure washer with hot water. Wear protective eyewear, sturdy shoes, and long pants. Use it at a pressure of at least 200 bar with a flow rate of at least 900 l / h (liters per hour). In this way, you will be able to descale any organic substance that has penetrated into the holes in the concrete. If you don't want to use the pressure washer, try a regular water hose.
- You can rent a pressure washer from a construction equipment company. You will likely need a van, pickup or SUV to transport it and a friend to help you load and unload it from the car.
- Ask the rental company how the car is used and what the safety measures are. Check if it has several nozzles. The jet must have a fan opening that does not drop below 15 °. Never mount a zero degree nozzle on a pressure washer.
Step 6. Wipe the inside with a cloth
Once dry, inspect it carefully to see if there are any traces of mold left. If they are still visible, rinse the washed area and try one of the more powerful methods you haven't used yet: diluted bleach or a bleach product.
Step 7. Clean the items you had put aside before putting them back
You can thoroughly clean leather, wood or synthetic furniture. Visibly moldy upholstery should be thrown away or replaced by a professional. Carpet should also be removed if it has abundant mold growth or is completely rotten.
Part 2 of 2: Eliminate the Source of Moisture
Step 1. Check if the ground is sloping or has accumulated debris
The cobblestones should be at a slight angle to the house so that the water runs away from the perimeter rather than gathering around the exterior walls. Do not allow damp leaves or other debris to accumulate around the perimeter of the building.
- Pool water could seep into the house and cause internal mold to form.
- If you see noticeable signs of mold in the driveway, consider removing any trees or bushes that obstruct sunlight. Mold grows in humid and shady areas.
Step 2. Find out how the water is drained outside
The wastewater drain must drain them at least 6 meters from the house. Gutters should transfer water at least 1.8 meters away from exterior walls. If the gutter pipes are channeling the water too close to the house, lengthen them.
Step 3. Check for water leaks
Make sure none of the outer tubes are dripping. Examine the perimeter walls for any leaks or water infiltrations.
Step 4. Stops internal leaks and limits condensation
If you have found any leaks - for example in the pipes or on the roof - do not hesitate to repair them. Insulate the roof, exterior walls, windows and pipes to reduce the moisture that causes condensation.
Step 5. Reduce the humidity in the house
If the problem is indoors, help ventilate the house to prevent mold from spreading thanks to the heat and stale air. Make sure that larger appliances, such as the washer and dryer, are placed in a sufficiently airy room. Make sure that the kitchen and bathrooms are well ventilated as well. Turn on the air conditioners and dehumidifiers as needed.
Step 6. Waterproof the concrete
Seal it with waterproofing products. Close any cracks in the driveway surrounding the house with concrete or tar. If you plan to paint your walls, use a waterproofing sealer first, then apply the stain primer and paint.
For exteriors, try a high-quality acrylic sealant for outdoor use. If the weather is hot and humid, find a low solids solvent-based sealant. Wait for a dry, sunny day to apply it, then let it dry for at least two or three days
Warnings
- If the mold has spread more than 1 square meter, it is best to contact a professional to remove it.
- Be careful not to spill chemicals between the plants.
- If your concrete countertop has become moldy, consult the manufacturer to find out how you can get rid of the stains.
