How to Remove Grime and Dirt Stains from Concrete

Pollution, grime, and dirt can build up to form stains which are dark in color, and can sometimes be oily. In general, they are mostly found in industrial areas, but can occur on any exposed concrete surface. However, such stains can vary in toughness, depending on the location, composition, age, concrete properties, etc.

How to remove grime and dirt stains from concrete surfaces: The various methods

In this article, we will present different methods on how to remove dirt stains from concrete depending on their toughness, covering light, medium, and stubborn ones. Besides, we will consider various chemicals and household products, in addition to proprietary cleaners, in order to provide a wide variety of effective methods.

Method #1: How to remove light dirt stains from concrete

This method is basic and is effective for the removal of light dirt stains from concrete patios, driveways, walls, and masonry. Mainly, it involves the use of detergents as the effective chemical.

Things you will need

• Gloves.
• Laundry detergent / dishwashing detergent.
• Stiff bristle brush / broom.
• Water.

Procedure

1. Put on your gloves.
2. Mix a household detergent with water.
3. Brush the surface with the cleaning solution using a bristle brush or broom.
4. Rinse and flush the surface with clean water.

Explanation

This simple cleaning method is sufficient to remove light dirt stains and grime from concrete surfaces. All it requires is brushing the surface with a mild solution which consists of water and a household detergent using a stiff bristle brush or broom, and then flushing it with clean water. In fact, the combination of the mild chemical agent and light mechanical action can help loosening up the water soluble surface contaminants to be flushed away easily.

Method #2: How to remove moderately stubborn dirt stains from concrete

This method is highly effective for the removal of moderately stubborn grime and dirt stains from concrete. Basically, it involves the use of a mild acidic solution which has little to no effect on the surface, unlike stronger acids which can attack concrete.

Things you will need

• Safety gear.
• Phosphoric acid.
• Watering pot.
• Stiff bristle brush / broom.
• Clean water.

Notes

• Phosphoric acid or Orthophosphoric acid.
  Appearance: Colorless granular solid (pure), or clear liquid (diluted or less concentrated).
  Availability: It is available at chemical supply stores.
  Hazards: This acid is toxic, irritant, and corrosive to flesh.

Procedure

1. Wear your safety gear.
2. Wet the surface.
3. Mix 1 part of phosphoric acid with 3 parts of water.
4. Scrub the surface with the acidic solution using a stiff bristle brush or broom.
5. Rinse and flush.

Explanation

In this method, the effective chemical for the removal of grime and dirt stains from concrete is phosphoric acid. First, put on your safety gear, then prepare the mild acidic solution by adding one part of phosphoric acid to three parts of water. It is important to note that you should add acid to water, and not water to acid. Next, wet the surface lightly with water, apply the acidic solution using a watering pot, and scrub gently using a stiff bristle brush or broom. And finally, flush the surface with clean water to remove any acidic remains and neutralize the surface.

Method #3: How to remove stubborn dirt stains from concrete

This method works great for the removal of stubborn grime and dirt stains from concrete, through the use of an acid. The main difference between this method and the previous one is that this uses a stronger acid, with a lower pH.

Things you will need

• Safety gear.
• Hydrochloric acid.
• Watering pot.
• Stiff bristle brush / broom.
• Clean water.

Notes

• Hydrochloric Acid or Muriatic Acid.
  Appearance: Colorless liquid.
  Availability: It is available at chemical or pool supply stores.
  Hazards: Highly corrosive, toxic, reacts vigorously with ammonia.
  Note: Always add acid to water and not water to acid.

Procedure

1. Put on your safety gear.
2. Pre-wet the surface.
3. Scrub the surface with a 5% solution of hydrochloric acid.
4. Flush the surface thoroughly with clean water.

Explanation

First, wear your protective gear when working with hydrochloric acid. Next, wet the surface with clean water to prevent the penetration of the acid into the pores of concrete. Then, add 1 part of hydrochloric acid to 19 parts of water, which yields a 5% concentration, and apply uniformly using a watering pot. However, as with almost any acid, it is important to add the acid to water and not the opposite. Then, brush the surface gently with a stiff bristle broom, and finish with thorough flushing with clean water.

In fact, it is crucial to remove any acidic remains, either through flushing with clean water or through the application of an alkaline solution to neutralize the surface. Besides, it is important to complete the process, from the application of the acid to the flushing, within 10 minutes.

However, although this method is highly effective, we recommend using other methods, such as the use of proprietary cleaners which are friendlier to the surface.

Method #4: How to remove various grime and dirt stains from concrete using proprietary cleaners

The application of concrete degreasers, or alkaline degreasers, is simple yet practical for the removal of oily grime and dirt stains. Mainly, the applicator should follow the product’s instructions with the handling and application of the particular, but we will present the typical method.

Things you will need

• Safety gear – depending on the product’s safety recommendations.
• Concrete degreaser.
• Bucket / watering pot.
• Stiff bristle broom.
• Clean water.

Procedure

1. Wear your protective gear.
2. In a bucket or watering pot, dilute the degreaser with water following the product’s dosage.
3. Apply the solution to the surface, and spread it uniformly using a broom.
4. Agitate and scrub the surface using a stiff bristle broom.
5. Rinse with clean water.
6. Repeat if necessary.

Explanation

The use of concrete degreasers is generally easy; all you have to do is follow the product’s instructions. In fact, one main advantage of such products is that they are specifically designed for concrete. Thereby, they do not harm or damage the surface, taking into account the frequent cleaning of the surface.

In general, concrete degreasers are available as concentrates, which require dilution with water. However, the amount of dilution usually depends on the extent of buildup and toughness of grime and dirt stains.

Method #5: How to remove grime and dirt stains from concrete using basic household products

Another highly effective method is to wash the surface first with an alkaline solution, then with an acetic acid solution.

Things you will need

• Protective gear.
• Tri-sodium phosphate (TSP).
• Bucket / watering pot.
• Distilled white vinegar.
• Stiff bristle broom.
• Clean water.

Notes

• Trisodium Phosphate: Other names include Sodium Orthophosphate, TSP, or Phosphate of Soda.
  Appearance: White crystalline odorless powder.
  Availability: It is available at the supermarkets.
  Hazards: It is corrosive to flesh.
• Distilled white vinegar.
  Appearance: Colorless liquid.
  Availability: It is available at the supermarkets.
  Hazards: This product is acidic, and corrosive.

Procedure

1. Put on your protective gear.
2. Mix 4 ounces of TSP per gallon of water in a bucket or watering pot, and apply to the surface.
3. Scrub the surface with a stiff bristle broom.
4. Rinse and flush.
5. While the surface is still wet, apply a 50:50 solution of white vinegar and water using a watering pot.
6. Gently brush using a stiff bristle brush.
7. Flush thoroughly with clean water.

Explanation

First, wear your protective gear, since both TSP and vinegar are corrosive to flesh. Then, in a bucket or watering pot, mix 4 ounces of TSP per gallon of water to produce your alkaline cleaning solution. Here, you can scale the proportions according to the area of surface. Then, apply the solution uniformly, spread it, and scrub using a stiff bristle brush. Afterwards, rinse the surface thoroughly with clean water.

Next, prepare the acetic acid solution by mixing equal parts of white vinegar and water in a bucket or water pot, apply to the surface, and gently scrub using a broom. And finally, flush the surface thoroughly with clean water.

Mainly, this process should neutralize the surface by itself. However, since you are not testing the pH of the cleaning water, it is important to properly flush the surface with clean water. In fact, this method is helpful in removing moderate to stubborn dirt and grime stains without the need for special products.

Other cleaning methods

Many other cleaning methods can also be effective for the removal of dirt stains from concrete surfaces, including steam cleaning and power washing.

In addition, if such stains are excessively oily, you can follow the removal methods for oil and grease stains.

Final thoughts

In this article, we provided various methods which involve different materials and chemicals for the removal of dirt stains from concrete, depending on their toughness. However, using a proprietary cleaner such as a concrete degreaser is the most preferable one.

Finally, after cleaning the bare concrete surface, it is a good practice to seal it. In brief, it is important to choose the adequate type of sealer depending on the application and exposure conditions.