Concrete requires periodic cleaning to remove dirt, growth and stains. A pressure washer, paired with a scrub brush or mop can help. PH-neutral cleaners are the best for most concrete cleaning. Acidic cleaners can damage polished or sealed concrete.
The most common discoloration of concrete is a simple buildup of dirt. A broom and water should clear up most stains.
Dirt
Concrete is a durable material, but it can be susceptible to stains from dirt, mildew, oil and other substances. Concrete cleaning regularly can prevent a buildup of organic stains and keep the surface looking new. The approach to cleaning concrete stains depends on the stain type and source.
Basic pH chemicals like sodium hypochlorite remove common stains from concrete surfaces, including mold, mildew and algae. However, they do not brighten the concrete like acidic cleaners, such as muriatic acid, can.
Organic concrete cleaners use enzymes and bacteria that actually eat or break down the organic materials that make up the stain. These products are available at pet stores as dog and cat urine odor and stain removers, through janitorial supply outlets and online directly from the manufacturers. They typically require at least 24 hours and sometimes up to 48 to complete their work. They also can etch or discolor polished concrete. Vinegar is another option for removing some types of concrete stains, especially rust stains. However, it is likely to damage any surrounding plants and must be diluted.
Grease
Grease is a mixture of oil and thickener that acts as a lubricant and a sealant. It protects a surface from contaminants like water and dust, reduces friction, prevents corrosion and resists leakage.
Greasy stains are a common problem on concrete surfaces like patios, driveways and sidewalks. Whether they are fresh or old, removing grease stains from concrete is a simple task with the right cleaning products.
Baking soda is a natural choice to remove grease stains from concrete because it’s less toxic than degreasers and is effective at lifting grease without damaging the surface. If the stain is very old, use a trisodium phosphate (TSP) solution to scrub and clean. TSP is an alkaline chemical that works well as a degreaser, cleaner and stain remover. To use TSP, mix it with sawdust in a bucket to form a paste consistency. Spread the poultice over the stain and let it sit overnight. Then sweep away the residue and rinse the area thoroughly.
Mildew
Like mold, mildew can leave unsightly stains on concrete. The fungus, however, poses fewer health and structural risks than mold because it simply sits on the surface of moist areas. It also has a powdery appearance that’s not as foul smelling as mold. However, inhaling mildew spores may cause sneezing and a runny nose.
If you notice mildew stains on your concrete, treat them with a basic laundry detergent or a concrete degreaser that is safe for use on masonry surfaces. Pour the chemical onto the stain and scrub with a brush before rinsing.
Alternatively, you can also purchase mildew remover sprays or acidic pH chemicals such as muriatic acid. These cleaners will remove both dirt and stains from concrete cleaning perth and can brighten the surface of the material. However, using these chemicals is dangerous and requires proper safety equipment. For this reason, it’s often best to hire a professional. They have the right tools and training to safely clean your concrete.
Mold
Mold thrives on moisture and can grow in the dark, shaded areas of concrete patios and driveways. It also grows inside basements and can result from a leaky water pipe, condensation on poorly insulated air conditioning ducts or other sources of excess humidity. Mold spores can be inhaled and cause allergic reactions in some people.
Mold can be killed by a number of different cleaners, including household bleach. However, be sure to test a small area before applying it and wear rubber gloves, safety goggles and a dust mask when working with any cleaning agent, especially bleach.
One product that can be used to kill and remove mildew and mold from concrete is Zep Concrete Cleaner, which comes in 1-gallon bottles. It contains chlorine and is safe to use on asphalt, brick and stone as well as concrete. To apply, pour on surface, scrub and rinse with a pressure washer with a high-pressure, wide nozzle.
