How to Sand Concrete? Tools for Sanding Concrete Walls, Floors, Patio, and Countertops

Can concrete be sanded down? How? Here’re the best tools for sanding concrete walls, floors, patio, etc., and ways to polish for a smooth finish.

If you are hoping to obtain a more finished-looking concrete surface on concrete floors, countertops, or a patio in your home, sanding the concrete might be a good solution for you. By means of hand sanding or power tools, you can sand your concrete surface to display a smooth, professional finish elevating the look of your home or business.

Can You Sand Concrete?

You can absolutely sand concrete to achieve a smoother surface. Sanding concrete floors, walls and cement surfaces can be a relatively easy task if you have the right tools and use the correct procedures. Whether you choose to use power tools or sand your concrete by hand, a little bit of elbow grease will leave you with a smooth, flattened surface that offers a more professional look.

Concrete can be sanded through a wet or dry process and the type of sandpaper and method you use will depend on this.

When polishing your concrete surface, think about the type of finish you are wanting to achieve. A smooth finish is great for countertops and similar surfaces and is best achieved through hand sanding. If you want to add a speckled finish to your concrete floors, consider a salt and pepper finish. This method requires you to remove about 1/16th of an inch off the surface of the concrete. If you take this method a step further, you can achieve an exposed aggregate finish. The amount of concrete removed can be as much as 1/4th inch depending on the amount of aggregate you want visible for your floor or patio surface.

Concrete Sanding Power Tools

When attempting to sand concrete, you can make the process much easier by using specific power tools. Depending on the size of your project, a hand-held concrete sander will work great for smaller projects while a walk-behind sander is your best bet for a larger project involving an entire floor. It is even possible to sand concrete with an angle grinder if that is your power tool of choice.

Hand-held Concrete Sanders

Using a hand grinder or orbital sander is a great option for sanding a concrete countertop or small surface. The small sander surface will allow you to have more control over tighter angles or corners of the concrete.

When using a hand-held concrete polisher, you will need to consider vacuum or hose attachments. Sanding will create lots of concrete dust which you should not be breathing in. A hose that can attach directly to your hand-held sander will use the flow of water to keep the dust down. A vacuum attachment will also collect the dust for future disposal. The type of sandpaper you use will depend on if you use a wet or dry sanding method.

Walk-Behind Sanders

A walk-behind concrete sander is your best option for a larger surface like a floor or outdoor patio. When polishing a larger surface with a walk-behind sander, it is important to be consistent with how much you sand in each spot. You will want to sand each location for a similar amount of time to ensure a uniform look.

Pic: Walk-Behind Sander – See Here to See Price

Walk-behind sanders can also be attached directly to hoses or vacuums depending on your preferred concrete dust mitigation method.

Sanding Concrete with Angle Grinder

While not always the first option you consider, you can sand concrete with an angle grinder. This option is best if you only have a specific spot you need to sand as the angle grinder wheel will only sand a small surface area. Use a diamond cup wheel when sanding concrete as other discs will wear down quicker and not be as effective.

Diamond Cup Wheel for Angle Grinder – See Price Here..

Bosch also makes a special attachment for angle grinder which is much safer to use.

What is the Best Tool for Sanding Concrete?

The best tool for sanding concrete will depend on the scope of your project. For sanding concrete countertops or other small, precise surfaces, a hand grinder or orbital grinder is your best option. If you want to polish larger surfaces, such as entire concrete floors, slabs, or patios, a walk-behind grinder will cover the most surface area.

For very specific areas that need to be sanded down, an angle grinder can be a good option.

Manual Sanding

If you do not have access to an electric concrete sander or polisher power tools or just have a very small surface area to polish, manual sanding could work for you.

Can you sand concrete by hand?

You can sand concrete by hand and the right grit sandpaper will help you get the job done. Do not forget that when sanding concrete by hand, you will still need to mitigate the concrete dust produced. Keep your work area wet to keep the dust down and consider wearing a face mask or dust mask.

You can get inexpensive hand polishing pads or use a sanding block with concrete sandpaper wrapped around it. Polish the surface in long strokes by applying uniform pressure throughout the stroke. As you remove the high points, the surface area of polishing will increase. Keep polishing until you are touching the entire surface equally.

You will want to choose sandpaper with the right grit depending on your project needs.

Type of Sandpaper for Concrete

The sandpaper you choose for sanding will differ completely depending on the type of concrete polishing you are doing. If you are doing wet concrete sanding, you will want to make sure your sandpaper is compatible with wet environments. You should also pay attention to the grit size of the sandpaper you choose based on the level of smoothness you want to achieve.

Start with coarse grit sandpaper and work up to superfine sandpaper for a perfect finish

What Sandpaper is Best for Concrete?

For sanding concrete, your best option is to choose diamond sandpaper which is made specifically for concrete, and masonry work. This sandpaper is actually made from diamond grits and not sand. The diamond grits are hard and resist wearing down better than sand when rubbed against concrete. Diamond sandpaper will last longer and be more effective overall in polishing masonry, stones, granite, marble, etc.

You will also want to make sure you purchase wet sandpaper or wet/dry sandpaper when complete wet concrete sanding. Regular sandpaper will become saturated and break down easier in a wet environment.

Can You Sand Concrete with Regular Sandpaper?

It is possible to sand concrete with regular sandpaper. Although it will not be as effective as concrete-specific diamond sandpaper, because the concrete mix itself contains natural sand or alternatives of sand in addition to cement. But it will still get the job done with a little more patience involved.

Pay attention to the grit you choose when using sandpaper. Basic sanding will require a sandpaper grit between 40 and 60. If your concrete surface has minor imperfections, you will want to use grit size between 80 and 120. For an almost perfectly smooth concrete finish, consider using an even higher grit somewhere between 200 and 400.

How to Sand Concrete to a Smooth Finish?

The process you use to sand your concrete to a smooth finish will depend on the type of project you are taking on. The size of the project and the location will alter the tools and methods that you use to polish. In any case, however, you will want to make sure you properly prep the concrete surface before you start polishing.

Remove any large irregularities on the surface such as bumps so you can achieve a uniform finish across the entire surface once you start the sanding process. You will also want to fill in any holes and remove any dust or debris.

Sanding Concrete Walls and Ceiling

You will want to use a hand sander or orbital sander for sanding concrete walls.

Here are the steps in the process.

1. Attach a diamond sanding pad to polish the wall.
2. Connect your water hose and begin applying the sander to the wall surface. Keep your pressure even to ensure a uniform finish. Keep the sander level.
3. Use a constant supply of water for the best results.
4. For tight spots where the concrete sander cannot reach, use a sanding pad and keep the finish similar to what you have already completed.
5. Once you have completed your first pass-through and all surfaces received an equal amount of polishing, use a sponge to clean off the surface.
6. If you have not achieved the desired level of smoothness quite yet, use a finer grade of sandpaper and repeat the process.
7. Once finished, allow the surface to completely dry. After a couple of days, apply a concrete sealer to protect the surface.

Concrete Floors

A walk-behind concrete floor sander works best for floors that cover a wide area. Before you start the process take a look around the room where you will be sanding the concrete floors to identify the things you want to protect.

1. Start the preparation by covering any walls, windows, and doors with plastic.
2. If you are sanding a large surface area, divide the floor into separate zones so that you can work on getting a uniform finish in each zone rather than the entire concrete floor.
3. Wet the surface and begin using your walk-behind concrete sander.
4. Start in one corner and move in a straight line to the next. Use straight passes and cover half of the previous pass each time.
5. If you run into any larger bumps in the concrete, go over them with multiple passes. Do not leave the sander stationary to avoid over sanding a specific spot.
6. Once you finish your first set of passes on the entire floor, fill any holes with an epoxy resin and allow it time to dry.
7. Begin the second round of passes in each zone and across the entire floor. This time, run the sander the opposite way than you did the first time.
8. Make two more sets of passes for a total of four. These next two should run vertically if you ran the first two horizontally or vice versa.
9. Once finished with all four passes, clean the entire floor and apply a concrete sealer. Allow ample time to dry.
10. For a smoother finish, repeat the process with finer grit sandpaper until your desired finish is achieved.
11. Once the finish of the concrete is to your liking, you can now apply a paint or stain to complete your space.

How to Sand Concrete Patio?

The procedure of sanding a concrete patio is very similar to a cement floor.

1. Before you start polishing your concrete patio, be sure to protect stairs, railings, or patio furniture nearby by covering it in plastic.
2. Follow steps 2 through 9 above as polishing your patio will require the same process as sanding a floor.
3. Once you have finished your initial four passes of sanding your patio, clean the entire floor and apply a sealer. Make sure that the concrete sealer you choose is approved for exterior surfaces and is a water repellant.
4. Repeat step 10 above until your patio surface is to the smooth finish that you desire.
5. Once the finish of the concrete is as smooth as you want, apply a paint or stain that is specified for exterior use. This ensures that the paint or stain will stand up to the elements and repel water.