Polishing a concrete surface begins with preparation. Clean the surface and open the windows to ventilate the room. Then, buy or rent a concrete grinder for the job. It is essential to wear protective clothing, as well as airway, eye, and hearing protection when grinding and polishing concrete. Once you are prepared for the job, grind the concrete surface, starting with a coarse grinding wheel and working gradually toward a fine grinding wheel. After grinding, use a roller to paint concrete densifier onto the floor. Then, the floor is ready for final polishing with a 3000-grit sanding disk.
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Can You Polish Concrete by Hand?
You can polish concrete by using a handheld, electric concrete grinder or angle grinder. However, you cannot effectively polish concrete without using power tools. Concrete is an extremely hard surface. Regular tactics used for sanding wood surfaces won’t work for concrete.
Can Concrete Be Polished with Sandpaper?
Unfortunately, you cannot use sandpaper to smooth and resurface concrete. The relatively thin and fragile sandpaper will tear apart before it grinds away concrete. Even power sanders such as belt sanders and orbital sanders are not capable of polishing concrete. For this job, you’ll need a polisher or angle grinder.
Can You Polish Concrete with an Angle Grinder?
If it is equipped with the correct grinding wheels, you can use an angle grinder to polish concrete. You can also use an electric polisher, which is very similar to an angle grinder. Whichever tool you use, you will need a set of concrete grinding wheels of different grits.
8 Steps to Polish Concrete by Hand
In order to take on the job of polishing concrete yourself, you need to follow a gradual grinding process until the concrete is worked to a smooth finish. The method below shows you exactly how to do that. You can use this method for grinding and polishing any concrete surface, including concrete floors and concrete countertops.
Prepare for Polishing
Before you begin the concrete grinding and polishing process, it’s essential to clean and prepare the concrete. First, vacuum the entire surface. Then, mop or wipe down the concrete with warm water and mild soap. Allow the concrete to dry before moving on.
- Vacuum the concrete surface you will be grinding.
- Mop or otherwise clean the concrete with warm, soapy water.
- Open all windows in the room where you will be grinding concrete.
- Cover vents with plastic sheeting and tape it in place—this prevents concrete dust from being circulated through your home.
Open all the windows in the room where you will be grinding concrete. This will help prevent dust and particle accumulation. Next, cover any air vents and air returns with plastic sheeting and tape the plastic in place. If concrete dust enters the air vents, it can be spread throughout your home. Since it is unhealthy to inhale concrete dust, it’s best to keep yourself and your family safe.
Wear Protective Gear
When you are handling a concrete grinder, always wear pants, a long-sleeved shirt, boots with toe protection, and a pair of sturdy work gloves. This equipment can help keep you free from accidental injury when handling a grinder or protect you from rebar poking through concrete.
- Sturdy work gloves.
- A long-sleeved shirt.
- Reinforced-toe boots.
- This particulate-filtering dust mask.
- Eye protection, such as heavy-duty glasses or goggles.
- Hearing protection, such as these earplugs.
It is essential that you wear breath protection whenever you are grinding concrete. Eye protection is also a must. Concrete dust can be extremely irritating to the lungs, airways, and eyes, so you should always wear protective equipment and work in a well-ventilated environment.
Buy or Rent a Concrete Grinder
If you are grinding a large area of concrete—such as the floor in an entire room—it is best to rent a large concrete grinder. These models work like a floor polisher—they allow the user to stand and move the grinder with a T-shaped handle. This avoids the backbreaking work of grinding a floor with an angle grinder.
- Rent this stand-up concrete grinder for grinding floors.
- Standing concrete grinders are best when grinding concrete floors before finishing them.
- When grinding concrete countertops, use an angle grinder or this concrete grinder.
- Handheld grinders are ideal for grinding and polishing small concrete areas.
Concrete grinders and angle grinders are the best choices if you are grinding concrete countertops, small surfaces, or contoured areas. They are far better at detail work, so it’s good to have one on hand even if you are using a stand-up grinder.
Choose a Set of Concrete Grinding Disks
In order to grind concrete effectively, you’ll need grinding disks in a variety of grits. For concrete grinding you will need disks of the following grits:
- This set of grinding disks is a great start.
In order to polish concrete, it’s essential to start with an abrasive grinding disk, then gradually work toward a finer grit. It’s a good idea to have several disks on hand, especially of the heavier grits (40, 80, and 120-grit) because they may wear out if you are grinding a large area.
Grind Your Concrete Floor
Begin grinding with either a 40 or 80-grit disk installed in your grinder. Grind in a semicircular motion. Make a half-circle arc back and forth, gradually moving forward to grind the entire surface. It’s essential that you do not leave the grinder in the same place for too long. Moving the grinder back and forth produces better, more even results than trying to grind concrete in a straight line.
- Begin with a 40-grit or 80-grit disk installed in your grinder.
- Grind the surface with back and forth, arcing motions as you gradually move forward.
- After grinding the entire surface with 40-grit, move to 80 grit, followed by 120-grit.
- Continue polishing with finer disks until you have completely polished the concrete with a 400-grit grinding disk.
After you have finished using the roughest grit grinding disk, move to a finer disk. Grinding disks—like sandpaper—are numbered. 40 grit is very coarse, while 400 grit is very fine. Always go in order, from the roughest disk to the finest. It’s important not to go back to a rough disk after using a fine disk. If you do backtrack in this way, you will have to gradually work through all the grades until you reach the finest disk again.
Vacuum and Mop
Once you have performed the final pass with your polishing disk, clean your concrete surface thoroughly with a vacuum. Use a bristle brush to dislodge packed dust from seams. Then mop the surface with soap and warm water.
- Vacuum, the concrete surface to remove concrete dust.
- Use a stiff-bristled brush to remove hard-packed concrete dust from corners and where concrete meets another surface.
- Mop or wipe down the surface with soap and warm water.
- Allow the surface to dry before taking the next steps.
Once the surface is thoroughly clean and dry, any stubborn dust should no longer be a problem. The surface just needs the final touches to prevent future dust problems and take on a polished shine.
Paint on Concrete Densifier
After grinding the concrete, next, apply a concrete densifier. This product fills pores in concrete, hardens it, and prevents concrete dust in the future. A densifier also provides an amazing polished concrete look. To apply densifier:
- Use this concrete densifier for your project.
- Equip a paint roller head with this ⅜-inch nap roller.
- Use a paint tray, roller, and roller handle to paint the concrete surface with a concrete densifier.
- Allow the densifier to dry.
- Wait 1–2 days for the densifier to cure before final polishing.
A single coat of concrete densifier is all you need. When you use a roller, there is no need to use multiple coats. Once you’re done painting the entire coat, allow the concrete to dry completely before walking on it or using the surface. Then, wait 1–2 days for the densifier to fully cure before moving on to the next step.
Perform a Final Polishing Pass
To truly polish your concrete after applying densifier, equip your grinder with a 3000-grit buffing disk. Alternatively, you can use an orbital sander or similar tool equipped with 3000-grit sandpaper for this final polishing. Use the 3000-grit to polish the entire surface with the same back-and-forth pattern used earlier for grinding and polishing.
- Equip a grinder with a 3000 grit buffing disk, or use these 3000 grit sandpaper pads on an electric sander.
- Polish the floor with the same arcing pattern used for previous grinding and polishing steps.
- Once this is completed, your floor is ready for use.
After this polishing pass, you may want to vacuum and mop your concrete floor once more. However, your work is done. By following this process you will achieve a polished, durable concrete floor that will not produce dust. The surface will be suitable as a countertop or a modern-looking finished concrete floor.
How Do You Polish Concrete at Home?
To polish concrete to a long-lasting, attractive finish yourself, follow these steps:
- Clean the concrete surface and ventilate the space.
- Wear protective equipment to keep yourself safe from injury, dust, and hearing damage.
- Buy or rent a concrete grinder.
- Purchase a set of concrete-grinding disks ranging from 40 to 400-grit.
- Begin grinding the concrete, starting with 40 or 80-grit, then gradually working up to 400-grit.
- Vacuum and mop the floor to remove concrete dust.
- Use a roller to paint the floor with 1 coat of concrete densifier, then allow it to dry.
- Polish the floor with 3000 grit sandpaper or a buffing pad.
This process yields professional results and a polished concrete floor. Although the process may be unfamiliar at first, if you take it step-by-step, you can polish a concrete floor yourself.