How to Remove Stains from Concrete

Concrete is durable and long-lasting but due to its porous surface, it is prone to staining from things like oil, mildew, paint, pets, and more. Taking the time to remove concrete stains can make a big difference in the appearance of your home. Most concrete stains can be easily removed using simple materials and methods.

Why Does Concrete Stain?

Concrete is a porous material and absorbs anything that sinks into the surface. As part of regular concrete maintenance, keep an eye out for spills and try to clean them up right away. The longer the stain has been there, the longer it will take and the more difficult it will be to remove.

Here are some of the more common causes of concrete stains and recommendations for how you can treat them.

Oil Stains

Most commonly seen on driveways and caused by motor vehicles. Best dealt with as soon as you notice is so it has little time to settle, since these stains can be particularly tough to get out. The stain can be blotted out with a paper towel, or it may need laundry detergent or a degreaser for tough-to-remove spills. You’ll want to let this sit overnight, and scrub with a soft brush followed by a water rinse in the morning. 

Another method for removing oil-based concrete stains is to sprinkle baking soda, cornmeal, or sawdust directly on to the stain, letting the stain become fully absorbed, and then clearing the powder away with a broom.

Paint Stains

Dried paint can prove to be challenging to remove if not dealt with before it fully dries. The color may not ever fully come out, but it can be minimized using a mixture of paint stripper and an absorbent material like baby powder or cat litter. Spread the mixture over the stain with a brush or sponge and let it sit for about 20 minutes. Then use a plastic paint scraper on the stain, and repeat the process if necessary.

Mold and Mildew

Rust stains occur when the concrete is exposed to the elements or iron patio furniture. There are a few ways to help this common stain. These stains are fairly easy to remove. For a newer stain, using an acid such as vinegar or lemon juice will do the trick. Pour the acid over the stain, let sit for 10 minutes, then scrub with a stiff brush. Rinse and repeat if necessary.

Some other methods that can be helpful for removing mold and mildew stains include using a commercial rust remover followed by a brush scrub and rinse. A pressure washer can also be effective for this type of concrete stain, as can a mixture of hot water and bleach applied to the area and rinsed thoroughly with water.

Stubborn Stains

Some concrete stains can prove to be more stubborn than others. If you need additional help in removing concrete stains, here are a few things you can try: 

Muriatic acid is a strong cleaning agent that can be used as a last-resort option for tough concrete stains. It should be used with extreme caution, as it can cause burns and severe damage to skin, eyes, and lungs. Heavy-duty protective clothing, mask, and eyewear should be worn, and all manufacturing instructions should be carefully followed. 

Trisodium Phosphate (TSP) is another strong cleaning agent that works well for mildew and paint stains. TSP is very strong and is banned in some states, so using an environmentally-safe alternative like TSP-PF can work as well. 

Sometimes, for really stubborn stains, it’s time to call in the experts. Contact us today for all your concrete maintenance needs!