Concrete has a rich history and continues to be a popular choice of medium buildings and even homes. While it is primarily seen in commercial buildings and sidewalks, concrete surfaces in homes are making a comeback. Sanded concrete surfaces are more attractive and practical compared to exposed ones. Several finishes can be achieved, such as smooth, salt and pepper, and exposed aggregate finish, and learning how to sand concrete could help you to get those results. The type of finish varies based on the tool and the amount of removal of the sanding.
Sanding a concrete wall or floor creates a more polished and neater look and gives a sophisticated and expensive natural look. With the help of tools, you can make the type of look you are aiming for. Manual sanding is often better for smaller surfaces such as countertops, where you use sandpaper, orbital sander, or hand grinder.
This article will discuss how to sand concrete floors, walls and the tools available for sanding concrete.
Best Tool for Sanding Concrete?
The choice of tool for sanding concrete heavily depends on the kind of area you plan on sanding. For example, sanding smaller surfaces like countertops, an orbital, or hand grinders are good options. However, a walk-behind grinder will be more appropriate for larger concrete surfaces such as floors, patios, or walls.
An electric sander or polisher is great for sanding, but manual sanding works fine too. Manual hand sanding requires grit sandpaper, but it requires constant cleaning of the pads’ dust. It also requires you to wear a mask and goggles. There are different kinds of sandpapers for this purpose, such as diamond grits, wet, and dry.
Choosing the sandpaper that has the right amount of grit is crucial for the sanding process. It depends on the kind of sanding to be done on a particular type of concrete surface. Basic sanding requires a grit of about 40 to 60. Minor regularities sanding needs a grit of about 80 120. Perfect finish smoothness will require superfine sandpaper grit, which often ranges from 200 to 400.
We will divide this guide into steps for how to sand concrete floors and how to sand concrete walls for your convenience. Both are broken down into steps for your ease.
How to sand concrete floors
In this section, we discuss how to sand concrete floors. Sanding concrete floors improves their appearance and removes bumps and blemishes to smoothen them. The time ranges from a few days to weeks – depending on the floor size.
You will need the following items before you begin:
- A concrete polisher
- Diamond grinding pads
- Walk-behind grinder
- Goggles, earplugs and a mask
- Sanding pads
Step 1: Preparation of floor’s surface
Before you start sanding your concrete floor, you must prepare the surface. First, clean the floor with water ad run a squeegee on it to eliminate unnecessary particles such as grit or dirt. If you don’t remove them, these can create gouges after you sand the floor. Remember that it is necessary to sand the entire area with floors, even if it may seem like some spots do not require it.
Step 2: Fill in the holes
Look for any flaws or holes all over the floor. This can be done with the help of a patching slurry. They come in a variety of colors to contrast your floor color. Fill in all the gaps or holes with concrete and let them dry before you begin sanding the floor.
Step 3: Polishing roughly
Usually, a walk-behind floor sander is the best tool for floors. First, divide your floor into zones to ensure each zone achieves the finish you’re looking for before moving on to the next one. Then, use a grinding pad to cover all nooks and crannies of the floor to ensure a smooth finish. During this process, make sure there is a consistent water supply, and the polisher stays leveled.
Step 4: Polishing finely
Once the floor has been polished with a course pad, use a finer pad for this step and repolish the floor. Then, repeat it once again with any other PD that you may have. After every polish, wipe the floor clean again to remove the debris and any dust that may have accumulated, so you get a clean canvas to work on every time and prevents imperfections as well.
There is no specific rule for the number of times you should polish the floor. Use trial and error, and once the floor is smooth and even, you will know. If the grinder cannot reach certain areas, you will have to sand that concrete area by hand with the help of pads. You can use pads to sand the areas with smooth strokes upwards against the coarseness, just like with the polisher.
Step 5: Let the floor dry
After polishing and grinding the floor, allow it to dry so that you can see the finished result correctly. Once it is fully dry, only then move on to the next step.
Step 6: Apply sealant
Apply concrete sealant to the floor as it helps the surface to keep free from stains and other wear-and-tear possibilities.
Maintenance of Sanded Concrete Floors
It takes a lot of effort to sand concrete floors, and so maintaining them is necessary if you wish to retain the look. Here are some tips you can follow to keep the good look of your sanded concrete floors:
- Regularly clean the floor with microfiber pads to gently remove the dirt particles.
- Use of only clean water and mops on the concrete floor.
- Use of neutral cleaners or especially concrete sanded formulas on the floor.
- Clean spilled liquids such as coffee or soft drinks as soon as possible to prevent staining.
- Allow the cleaner to stay on the surface for a while to destroy the grime and other substances.
How to sand concrete walls
Like sanding concrete floors, concrete walls require different tools as the area is harder to access than a floor, but this process is very similar to the one above for concrete floors. You will need the following items for sanding your concrete walls:
- A concrete polisher
- Hand or orbital sander
- Diamond grinding pads
- Fine sandpaper
- Concrete sealer
- Water hose
Step 1 : Preparation of the wall’s surface
Before you begin sanding your concrete wall, surface preparation is essential. First, clean the wall with water to get rid of grit or dirt particles. Then, just like with concrete floors, they need to be cleaned to prevent gouges sanding.
Step 2 : Polish the main areas
Attach a diamond grit sandpaper to polish the wall. First, make sure the water hose is being used to clean the wall. Next, apply the sander and ensure that the pressure is even for a more uniform finish. Like with the sander, having a constant water pressure supply will help give the best results.
Step 3 : Polishing the harder to reach areas
After polishing the easier-to-reach areas, use a sanding pad for the tighter spots. Make sure to keep the surface finish similar to what you have achieved in the last step. After the entire surface has been polished, use a sponge to clean the surface to eliminate any leftover concrete grit.
Step 4 : Repeat the process (optional)
Sometimes the level of smoothness has still not reached your desired level. In this case, use finer sandpaper and repeat the process. This is usually recommended with larger surfaces as it is easy to miss a few spots.
Step 5 : Let the wall’s surface dry
After sanding the wall, allow it to dry to see if the sanding was even and uniform. Only when it is fully dry then move on to the next step. Usually, with larger surfaces, such as walls, it takes more than a day for the surface to be completely dry.
Step 6 : Apply sealant
Once the wall has dried, apply concrete sealant to protect the wall from any wear and tear. Do not apply before at least a couple of tests – after the concrete has been sanded.
Frecuently Asked Questions
Can regular sandpaper be used to sand concrete?
While regular sandpaper can be used for this purpose, it is not recommended. Even if you are using a sander, regular sandpaper will require much time to finish the process. Thus, using a diamond or grinder sandpaper is recommended.
Is it possible to sand down concrete?
Sanding concrete is a prevalent process to make the concrete surface smooth. It is usually achieved through dry or wet sanding and the kind of sandpaper you are using. Polish the concrete is excellent for whichever type of look you are going for. Hand sanding is good for smaller surfaces such as countertops. This video is perfect for beginners.
How long does the sanding process take?
Concrete sanding can take up to 6 hours if it is a 500 ft of surface. More rigid concrete, however, takes longer, and larger areas take longer. However, the type can vary as you also have to clean and prep the surface before. So, there are a lot of considerations for this.
Why do people sand concrete?
Sanding concrete is a great way to remove imperfections, build-up, dust from your concrete surface. It also helps even out the concrete surface to restore it and make it look brand new and aesthetic. Thus, old concrete surfaces can be made to look fresh with just a few steps.
Sanding Concrete surfaces such as walls or floors can be a little bit time-consuming depending on the finish you’re looking for, but we’ve seen that if you follow the steps mentioned above, you can get incredible results. Every time you’re going to sand concrete areas, remember to always analyze what type of concrete are you going to work with, so you can use the correct type of sandpapers and tools to achieve a smooth finish, and don’t forget to do the proper maintenance to your sanded concrete surfaces if you don’t want them to look old again.