The best way to approach cleaning is always starting by removing dust & debris from the area. Try cleaning the area with laundry detergent-water mixture or dishwashing liquid-water mixture.
For specific stains on the concrete, opt for commercial cleaners that target the particular type of mark or stain. Move on to hard chemical cleaning solutions only if these products do not yield satisfactory results as most of them have damage potential to the concrete and us. Always approach cleaning from the least aggressive to aggressive.
An exact cleaning regimen might not be possible as there are different types of concrete, stains on these surfaces, and the sealers used to protect the concrete. Follow the steps below and adjust cleaning methods and solutions according to your needs.
Why Do We Clean Concrete Surfaces
We clean concrete surfaces for either of the two reasons:
- Maintain & improve the concrete surface for a better appearance.
- Prepare the surface for further treatments, sealing, overlay, and development.
Considerations to Remember
- Always dampen or wet the concrete area before applying any concrete stain removers, especially acidic alternatives.
- Always rinse the area with clean water after removal solvents treatments. The residue of these solvents will damage the surface.
- Multiple applications of the cleaning process may be required depending upon the frequency of daily cleaning done in the past, type of stain, the purpose of cleaning with some slight adjustments.
- There is a good chance that shadow residue of the previous stain may remain due to the depth of penetration in the concrete pores.
- Chemical-related/acidic stain removal methods can often leave lighter color shades in concrete due to the properties of hard chemicals used.
- Hard acidic alternatives like hydrochloric or muriatic acid on white concrete may leave a yellowish tint on the surface in high concentrations.
- Always apply these solutions in the section. We recommend two-by-two feet as a standard. The reaction of these alternatives may have different results on various types of concrete.
- Most hard chemicals are toxic and often flammable.
- While mixing solutions, always add acid to water, never water to acid to avoid spontaneous exothermic reactions.
- Proper masks, gloves, and ventilation are the bare minimum precautions to be followed. Health hazards are an actual concern while using these solutions.
- We should identify the stains before following through with the removal method.
- These solutions are mere starting points. Do not expect a once-and-done result.
- Acidic solutions are very dangerous. Based on application, improper dilution, erratic pouring, and many external factors, results might skew positively or negatively. Please use these methods with extreme caution and at your peril. Whenever in doubt, consult a concrete professional.
How to Clean Concrete
For everyday cleaning on concrete, we recommend the following procedures. You should always try methods with the least aggression and abrasion to high aggression.
Always follow the protocol of starting from Mild detergents/soap with no bleach to commercially packaged cleaning solvents to tougher methods using chemicals.
Chemicals affect the surface negatively, and we recommend using chemicals only if there are no other alternatives.
- Broom/Microfiber Mop/String Mop/Push Broom (No wired Brushes)
- Vacuum Cleaner
- Mild Detergent/Soap
- Specific Commercial Cleaning Agents
- Cloths, Rags
- Masks and gloves are compulsory for chemical alternatives.
General Steps for Regular Cleaning
- Clean all the dust & debris on the concrete surface with a broom and dustpan or vacuum.
- Get around two buckets of warm water.
- In one bucket, apply some mild liquid dish soap or detergent. For general cleaning, we do not recommend washing products with bleach.
- Mix both detergent/soap and water in the bucket to create a cleaning solution. There are also commercial cleaning solutions that we can get in the market made for daily concrete cleaning.
- Be extra careful about cleaning agents for epoxy, polished concrete painted, or sealed concrete. Always check the compatibility of the cleaning agents on the type of concrete you have.
- Apply the soapy water or cleaning mixture with the mop. Always wring mops while using them on the surface. Our goal is as little moisture as possible. Be mindful of the excess amount of water being released.
- Once the whole area is done, wring the mop from any soap.
- Use the wrung mop with clean water and mop the floor. Wring the mop for any excess.
- Repeat the process until satisfied.
- Once the soapy water cleaning is done, empty the buckets. You will notice the dirt in the water from cleaning.
- Fill the bucket with fresh water. Clean the whole area with fresh water. Do not drown the floor with water; wring a mop and do the cleaning pass.
- For epoxy floors, do the same method specified above. Be sure to use some rags or old towels and do a wiping pass to help dry the concrete after the cleaning is done.
- For polished floors in a commercial or industrial area, mopping might be a big task; we can use autos scrubbers to clean the floors better than the mop system. In the absence of these machines, the mop system will do fine.
If you do regular cleaning of concrete surfaces, chances of staining go way down. Make a habit of creating a regimen for cleaning.
How to Approach Particular Stains on Concrete
Follow the alternatives below to remove a specific type of stain on concrete. Please note that there is a good chance that if the concrete is sealed, hard chemicals can damage the sealant when using these methods.
We recommend sealing the floors every year to protect itself against stains, dirt, and debris in the future.
- The first mode of action should be to clean the stain with some warm water mixed in with mild detergent or soap if the stain is still present after this application. Other stronger alternatives to try out are stated below.
- Glycerol-water mixture is a good alternative in the ratio of 1:4. We can add rubbing or isopropyl alcohol according to need.
- A poultice of absorbent materials like talc mixed in with trichloro-ethylene will work for stubborn stains. The above-stated methods apply stains caused by coffee, tea, or alcohol stains.
- We recommend dampening the area first with clear water.
- Sprinkle some sodium peroxide powder on the stained area and apply some water. Alternatively, we can use a rag or saturated rag with water and let the rag sit for a period.
- An alternative solution is hydrogen peroxide or trisodium phosphate instead of sodium peroxide.
- Scrub using a soft-bristled brush and rinse with clear water.
- Ensure you neutralize the acidic solution with a vinegar-water mixture. The concentration of vinegar is recommended to be at 5 percent.
- Rinse again with clear water and let the area dry completely. Repeat the process if necessary.
Tobacco or Smoke Stains
- Approach the tobacco stain with a poultice made from grit scrubbing powder and hot water.
- The paste layer should average about half an inch. Let the poultice dry and scrub with clear water. Repeat the process as necessary.
- For tough smoke stains, the best poultice to use is trichloroethylene poultice. Application is the same as the tobacco stain poultice. We can also use powdered pumice.
Calking Compound Stain
- Approach the compound stain with a soft-bristled brush and scrape as much as possible.
- After the scraping is done, apply a poultice with denatured alcohol. Wait a bit of period till the calking compound start becoming brittle, and then brush it off.
- Rinse the area with soapy water or Trisodium phosphate and finish it off with a clear water rinse.
- Let the area air dry completely or help in drying with a clean rag.
- We recommend first trying with some WD 40 multi-use product and some elbow grease.
- In the worst-case scenario, opt for the following solution:
- Rust stains can be dissolved with oxalic acid powder. You can buy specific rust stain removers for concrete in the market. We recommend them as your primary method of removal.
- Some popular brands are chomp it out, Singerman, Iron out, etc.
- For harder methods, you can directly use powder. The dilution range is around 1 pound per 3.8 liters of water. Mop the area with this solution. An alternative to this can be ammonified solution of thioglycolic acid.
- This stain can be identified as deposits of white color. It may occur in both new and old concrete.
- Wet the surface and try removing the efflorescence with a soft-bristled brush done with a mixture of soapy water. We can remove most water-soluble compounds with this approach.
- For stubborn water-insoluble compounds, we will need muriatic acid. The highest concentration ceiling is ten percent. Always start with a lower concentration and move on to a higher concentration.
- If the concrete is colored, your concentration ceiling should be around one to two percent. High concentration will result in etching or color change.
- Other alternatives are a phosphoric acid-water mixture in the ratio 1:9 or phosphoric, acetic acid, and water ratio of 1:1:19.
- Brushing the surface should be done at an average of 5 to 10 minutes delay after using these solutions.
- Rinse the whole area with clean water and let it dry completely.
- We recommend treating the entire concrete area to maintain a uniform appearance and avoid color variations.
- Please opt for saturating the stained area with water to dampen the surface.
- Apply a hydrochloric acid solution at a max concentration of ten percent, depending upon the need for aggressiveness.
- If the concrete is colored, apply for a weaker concentration.
- Rinse the area with clear water after treatment is done.
Copper/ Bronze Stains
- We can identify these stains as bluish-green stains on the concrete. The best way is to mix absorbent materials like clay, talc, calcium carbonate with ammonium chloride.
- Our goal is to make a poultice. Place the paste over the stain and let it dry.
- Scrub the area with clear water later to remove residue.
- Repeat the process as necessary.
Oil & Grease Stains
- Scrubbing is the universal method for grease-related stains as it does not penetrate the concrete. We recommend detergent/soap water mixture, trisodium phosphate-water mixture, or commercial degreasing options.
- Suppose the stain is still present. A poultice is a way to go. We can use mineral spirits, trichloroethylene to make the poultice. Apply the absorbent poultice to the stain & let it dry. Scrub the area with soapy water or trisodium water mixture and rinse with clear water later.
- In terms of cleaner, alkaline-based solvents are recommended. In large areas, butyl-cello solve or metasilicate will work too. Other alternative solvents to try out are sodium carbonate, carbon tetrachloride, and chloroform. Remember, proper ventilation is a must.
- Oil, on the other hand, does penetrate the concrete. Use plenty of absorbent materials on the surface with plenty of paper towels or cloth. Later ty scrubbing with soapy water, trisodium water mixture, or detergents.
- There are plenty of oil stain-specific commercial removers. We recommend them as primary methods.
- For worst-case scenarios, use trisodium phosphate and water mixture in the ratio of 1:6 with poultice and apply to the stain and leave it for an average of 24 hours. Remove the paste and scrub with clean water.
- Other poultice options are caustic soda at 5 percent concertation. We do not recommend any benzene-related poultice as they are very toxic.
- If the paint is wet, always try to absorb as much as possible with plenty of paper towels, rags, or cloths.
- Wiping isn’t recommended as spreading will most likely occur. Scrub as much as possible with detergent water. Let the paint dry after assessing that is the best effort done.
- Scrape as much dry paint as possible. Apply a poultice with a commercial paint remover. Allow the paste to stay there for an average of 20 to 40 minutes and scrub gently to remove the paint.
- Once done, try the soapy water scrubbing again.
- There are plenty of commercial paint remover options available for concrete areas. Those should be your primary go-to options.
- The methods specified above can also work for varnish or shellac stains.
- We recommend using commercial graffiti stain removers easily found in the market for graffiti stains or spray paint.
- Removing paints also depends on the paint used; there may be paint-specific solutions to clean paint stains off the concrete.
- The go-to method for removing tire marks from concrete is always soapy water.
- Opt for commercial degreasing options if the stain is still present.
- In worst-case scenarios, you may have to use acidic solutions like muriatic acid, trisodium phosphate solutions, etc.
- Apply the same poultice methods specified for some stains. You can also opt for the trisodium phosphate-water mixture or use a strong detergent on the surface.
- For older tough stains, you can use trisodium phosphate crystals mixed in with water and chlorinated lime to make a poultice in the ratio of 2 pounds:3.8 liters of water:0.34 kg of chlorinated lime. This poultice is corrosive towards metal, fabrics, etc., so be extra careful and only apply it to the stained area.
- We recommend doing this only if you plan to add a sealer afterward.
Moss & Mildew/Microorganisms
- There are plenty of commercial mold and mildew stain removers in the market. We recommend approaching the stained area with those products first.
- We can use ammonium sulfamate for moss. This chemical is found in local stores for tougher methods. Another alternative to use is sodium Penta-chloro-phenate and water mixture in the ratio of 1:8. We can use this solution to saturate the moss area and scrub it with a brush.
- For mildews, we recommend a cleaning mixture in the ratio of 0.03 kg detergent:0.09kg trisodium phosphate,0.95 liters bleach:2.8 liters of water. Apply the solution on mildew, scrub with a soft-bristled brush and rinse later with clear water after treatment.
- We can remove microorganisms such as algae lichens with a cleaning solution of household bleach with a concentration ceiling of 5 percent formaldehyde with a concentration of 2 percent with a little bit of aqueous methanol.
Aggressive Methods for Cleaning Concrete
We recommend the following alternatives with professional supervision.
Sandblasting is a process where we drive abrasive grits on the surface to erode the coatings, dirt, debris, paint splatter, contaminants, etc.
Please note that these processes will most definitely change the appearance of the concrete, and the texture will get rougher.
These machines use coarse grit pads, stones, papers to remove the layer of the concrete. There is a lot of dust created using this process, but it is an excellent alternative when refurnishing and recoating.
There are specific procedures to be followed while sanding concrete surfaces. The surface will also need to be sealed afterward.
As the name suggests, we wash the concrete with pressurized water. This method will remove deposits of dirt. Machines up to 55000 PSI are available in the market. However, a 500 PSI will generally do the job.
There are also other alternatives where sand can be injected into the water stream to enhance cutting. Water pressure washing will remove dirt stains and abrade the surface for repairs. It is also helpful to remove weak and deteriorated concrete.
A multi-flame blowpipe is used over the service, which causes the concrete to shave off aggregates,
oil, paint, and other impurities. The moisture of the surface also gets evaporated. The gas pressure also helps remove loose materials and exposes a new surface.
Generally, a concrete steam cleaner is used where the water is directed toward the machine’s boiler to create steam. This method is helpful, especially after acid etching, as it helps to remove deep-seated soiling.
How to Maintain Concrete
- Follow the simple guidelines to keep your concrete floors clean and maintain them over a period.
- Always use PH-neutral cleaners for general cleaning. Always opt for cleaning solvents made for the concrete floors for epoxy, polished, or any decorative concrete.
- Spills should be cleaned immediately especially concrete floors. Leaving a spill on for a period will result in the spill penetrating or eating away the sealer.
- Always try cleaning stains first with normal soapy water commercial concrete floors cleaners.
- Do not use citrus, acidic products for general cleaning. Sometimes, for specific stains, those products may be unavoidable.
- We recommend using walk-off floor mats for indoor concrete to minimize dirt and debris.
- Clean any Sand or any agent with grit with broom and dustpan as they act as natural sandpaper for sealed or epoxied floors.
- Consider refurbishing or resealing the surface every year or two.
- Dry clean indoor concrete every day. We can wet mop 2 or 3 times a week.