Removing rust from concrete can be challenging, as you’re often trying to tackle a large area. That said, we covered some easy ways on how to remove rust stains from concrete.
When you notice rusty stains that have formed on your cement driveway or sidewalk, you should definitely try to remove them as soon as possible.
The longer the stains have to work on your concrete surfaces, they become more embedded, and the more damage they will do. So let’s find out how to remove rust stains from concrete.
How To Remove Rust Stains from Concrete
Table of Contents
- 1 How To Remove Rust Stains from Concrete
- 2 Causes of Rust Stain on Concrete
- 3 Preventing Rust Stains
- 4 Conclusion
First, rinse the area with soap and water, try to get rid of dust and dirt from the area as they can get between your cleaner and the stain, making your work less effective. After properly cleaning the area, allow it dry before proceeding.
Using Lemon Juice/Vinegar
This is both great solutions to rust stains due to their acidic content; you want to use them in their undiluted concentration as they are more powerful that way.
Apply the lemon juice or vinegar all over the rusted surface and allow it to sit and penetrate the rust for at least ten minutes; then, using a wire brush, scrub the rusted area using enough pressure.
Work in small circles to remove as many of the rust stains as possible, then rinse off the area with cool water. You want to avoid metal bristles as it can damage the top paste layer in the cement and expose the material underneath it.
After rinsing, allow the area to dry properly; you may need to repeat this process a couple of times as multiple washing is often the best way to fully remove rust stains.
If the rust stain is in hard to reach areas, you can use a spray bottle to apply either the lemon or vinegar solution. If the rust stain is close to plants or foliage, you need to be careful with the application as the high acidity content of both solutions can damage plants.
In this case, you will need to dilute the solution so it wouldn’t have much effect on the plants, but you would have to put in more elbow grease to make up for the dilution.
If the affected rusty area is painted or delicate, you will have to opt for a sponge in replacement of a brush.
If you have a painted surface, you want to test the cleaning products on a small section first to make sure it is safe to use because most acidic solutions tend to ruin the paint.
When working with a painted surface, you will need to dilute you will also need to water down the acidic solution you are using; for every 1 cup of solution, you need 1/2 cup of water, and you want to scrub in a gentle circular motion, you may have to repeat the process up to four times.
Using Commercial Cleaners
If the lemon juice/vinegar procedure doesn’t work, you need to move onto heavy-duty commercial cleaners.
When using this type of product, you want to make sure your working area is properly ventilated, and you will need to put on some protective clothing like gloves and eye protection, and if you are working in an enclosed space, you will need a ventilator.
You also need to wear long-sleeved shirts and pants to protect your skin. You also need to make sure that there is no pet or little kids around your working area.
For this procedure, you will need to buy a commercial rust remover that contains oxalic acid. These products usually come in liquid or powder form, they often used to scrub sinks without scratching them, and they will effectively remove rust stains.
If you are making using of a powder product, you will need to dilute it with water, apply the product on the rusted area and allow it to sit for a couple of minutes.
You can also make use of Trisodium Phosphate (TSP) to remove rust stains. Simply mix 1/2 cup (118.29 ml) of TSP with 1/2 gallon (1.89 L) of hot water, and apply it to the rusted area. Then allow it to sit for at least 20 minutes.
Once the products have had enough sitting time, take a stiff-bristled brush to brush the surface gently in circular motions; as stated earlier, you do not want to make use of metal bristles as it can damage your surface.
After scrubbing the area to your satisfaction, rinse away the product making sure no residue is left as it could cause discoloration if left on concrete too long.
This is another feasible solution to rust stains. You will need to mix the detergent with some baking soda to give it more cleaning strength; although there is no exact measurement, you can make use of two parts detergent and one part baking soda.
Apply this mixture to the rusted area and allow it to sit for at least 10 minutes before using a brush to gently but firmly scrub the surface, after which you rinse thoroughly with water.
Carbonated drinks like Coca-Cola can be used to remove rust stains. All you need to do is pour some of the liquid over the rust stain and allow it to sit for about ten minutes. Then using a brush, scrub away the stain, and rinse thoroughly with water.
While this might be the most effective way to remove rust stains, it can tint your concrete blue if left for too long. Hydrochloric acid is also known as muriatic acid, and you want to make sure you wear protective clothing before handling this acid.
You will also need to dilute this acid by mixing 1 part of water for two parts of acid to give yourself more time and avoid re-coloring your surface.
You must pour the acid into the water and not the water into the acid. This is to prevent any violent exothermic reactions. Apply the mixture to the rusted area, and it sits for no longer than ten minutes; then, using a brush, scrub the stain away, and rinse thoroughly with water.
If the rust is in a hard to reach area or can’t scrub the stain properly, simply apply the rust removal product of choice, allow it sit for the recommended amount of time, then set up a pressure washer; its concentrated force helps to act as a scrubber and also rinses the product away.
Causes of Rust Stain on Concrete
Loose iron or steel particles are the major causes of rust stains or marks on concrete. Reinforcing bars close to a concrete surface can leave behind marks of their presence, especially when the bars are not protected against corrosion.
Also, Incorrectly positioned reinforced bars can also cause rust stains or marks, as well as bars that often come in contact with water and concrete.
If there is frequent water contact with Your concrete patio, driveway, or porch, especially if the water is flowing out of natural stone, or the water is rich in minerals. The minerals can accumulate, get oxidized, and turn reddish-brown.
Leaving out a metal tool in the rain or having A radiator leak is also a cause of rust stains and marks. If these items are left in contact with concrete, they can cause discoloration.
Preventing Rust Stains
Positioning iron bars at least a few inches away from concrete, finishing them with an erosion-resistant material, and keeping it at a safe distance, so it does not come into frequent contact with water will help to prevent rust stains or marks on your concrete floor.
Some regions tend to have naturally high concentrations of metal in them. So if you live in that type of region, you can reduce the harmful effects of excessive metal by saturating your water with baking soda or another chemical base with high pH value.
Applying a sealant
Applying a concrete sealer helps to protect the concrete from stains by soaking into its pores. Concrete sealers can be purchased at any home improvement store, and it should be reapplied every 2-3 years for maximum protection.
To apply a sealant, all you need to do is simply wash the concrete surface to remove any stain the starting at a corner, roll the sealant onto the concrete, then allow it to sit for 48 hours before placing anything on it.
Try to keep your patio clean as much as you can. Keep all metal tools properly, and remove the wet ones as soon as you notice them.
You can also place felt runners or outdoor mats to protect your concrete. You can try applying a sealant to your metal furniture to prevent rust. You can also apply a sealant to already rusted furniture to prevent the rust from spreading to your concrete.
Inspect your home for leaks
If you are experiencing rust stains on your concrete surfaces, you should try inspecting your home for leaks as moisture can cause rust; the sooner you are able to find the source of the leak, the earlier you will be able to fix the leak and prevent further damage.
Rust stain on a concrete surface can totally ruin the look of the area, and the longer the rust stain has been on your concrete, the more difficult it will be to remove.
After finding out how to remove rust stains from concrete, you want to apply the steps with utmost care and caution to prevent damage to your concrete surface.