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How to Sand Concrete?

How to Sand Concrete?

More and more people are opting to have exposed concrete floors in their houses.

They are easy to clean and maintain, and when well maintained, can be quite attractive. 

But before you can worry about maintaining your flooring, you have to prepare it.

And a big part of preparing it is making sure that the  surface is smooth, level, and clean. 

Probably the most significant part of working out how to have a smooth, level concrete floor is figuring out how to sand down concrete the right way..                                

And while figuring out how to sand concrete flooring isn’t the world’s most complicated task, it’s also probably not something that you have done before. 

It’s even more challenging if you’re trying to understand how to sand a concrete floor by hand, as most of the prescribed methods online use machinery that can be expensive and difficult to use. 

There are many different viewpoints on this out there, and it is challenging to know which method is the best and why. 

Let’s take a look at both of these methods. Don’t worry, we’ll keep everything simple…because sanding a concrete floor is already hard enough work as it is. 

Things You May Need:

Why Should I Sand My Concrete Floor? 

There are many reasons to want to sand a concrete floor or surface. 

Maybe you want to cure, finish, or paint the exterior. Perhaps it’s part of a more significant finishing project, such as completing a basement floor. 

Or maybe there’s a bigger problem you are trying to fix. Possibly the floor was somehow damaged, is rough or uneven after removing tile thinset, or was poured poorly in the first place. 

There are many other reasons that you should consider sanding, but whatever the reason the process is mostly the same. 

Regardless, a lovely smooth floor is an essential aspect of any room.

And beautiful smooth concrete has a special glean to it. 

Plus it’s practical and easier to clean and maintain than most other common types of flooring. 

How Practical Is Sanding Concrete? It’s a Very Hard Substance

sanding concrete

But is sanding concrete even possible? It’s a tough surface, like rock. Wouldn’t it be very challenging? We’re not talking sanding drywall here…

Can it be done effectively by hand, or do you need the right machinery?

The good news is that it is possible. 

And as long as you have the right tools, it is not even that difficult, although it can be time-consuming. 

You also need to choose the best method to save yourself from wasting a lot of time. 

Whether you are completing the project by hand or with a machine, you will need proper concrete sandpaper. 

This sandpaper is made using diamond when traditionally sandpaper is made using sand.

If you don’t use the right sandpaper, you will not be able to complete the job. It’s critical to your overall success. 

Using the incorrect type of sander may seem like an easy solution, but at best, you will make zero progress and frustrate yourself. 

At worst, you will severely damage the concrete, which will cost a lot of time and money to fix. 

You will also need patching sully that matches the color of your concrete.

This is particularly essential if you are repairing the surface, but should be purchased regardless in case of mistakes. 

These are not areas you can choose to skimp on, and if you do, it will cost you later. 

What Do I Need to Do After Sanding Is Completed? 

Well, to begin with, enjoy your fancy and super smooth new concrete floor. 

But after sanding it is also critical to seal and finish your concrete to avoid problems further down the line. 

Sealing and finishing help to prevent future damage to the floor, plus can have a beautiful aesthetic after effect. 

While the most common finish is still a basic, smooth grey, there are more decorative options such as speckled salt and pepper finish and exposed aggregate finish. 

How-to Steps

Whether you are sanding with a sander or by hand, the process itself is relatively similar.

The main difference is, a sander is a much quicker and easier method. 

Alternatively, doing it by hand is more precise and can yield a more beautiful result. 

Generally, I would recommend using a sander if you are dealing with a large space.

 If the area is small, and particularly if you are dealing with a countertop or something where a specific look is vital, I would recommend doing it by hand. 

But I’m not going to make the whole ‘by hand’ or ‘with a sander’ decision for you. 

It’s up to you, how much time you have, and the desired final product. 

You need to think about what end result you are hoping to achieve and then use this to make the most informed decision. 

1. Preparation Phase

preparation phase

As in any DIY project, the key to an excellent final product lies in proper preparation and having all of the right tools. Sanding concrete is no different. 

First and foremost, you will need the correct sander and sandpaper.

The DEWALT Rotary Sander is an excellent all-around sander that doesn’t completely break the bank. 

As previously mentioned, you will also have to be sure to get diamond-based sandpaper. 

You will also need the patching slurry that matches the color of your concrete, a sponge, protective gear (work gloves and a face mask), cleaning solutions, a level, and a vacuum cleaner. 

And once you have all of the right supplies, you need to prep the area and the surface. To start, this means doing some serious cleaning. 

First, sweep or vacuum. Make sure that you have gotten rid of any dust or other debris. 

Once this is done, mix ? of a cup of Trisodium Phosphate, 1 qt. Chlorine bleach, and a gallon of warm water. 

Stir it with a mop and mop the floor thoroughly. Repeat this until the floor is sufficiently clean. 

Let the floor dry for a few days, and then you are ready to start sanding. 

2. Beginning to Sand

If dealing with a large space, it is crucial to work in sections, particularly when sanding by hand. 

You should partition off areas of about a square meter to work on. This is most easily done by laying down tape. 

Once you have laid out your sections, you can start sanding, preferably with a space in the corner of the room. 

It’s best to leave the main part of the room for a bit later, once you’ve gotten the hang of it and are on a roll. 

Be sure to wear a face mask and safety goggles to keep the dust out of your eyes and nose. 

This is essential when sanding anything, but particularly critical with a hard substance such as concrete.

You don’t want to cause yourself future health problems that could be serious.

An electric sander will create even more dust more quickly than a sanding block or hand sander, so it is particularly vital to make sure that your eyes and nose are protected when using either. 

And be sure to change the piece of sandpaper when it becomes too smooth. 

On more stubborn areas, you may have to use a lot of sandpaper. There is no point in trying to save it.

Change it out before it has become entirely smooth or you will be working hard for nothing. 

3. Cleaning and Leveling Along the Way

removing concrete toppings

Periodically during the process, depending on the amount of dust build-up, you will also need to sweep or vacuum the space. 

The best method is with a shop vacuum or any vacuum that has a crevice attachment. 

Be sure to keep your mask and goggles on during the process. 

It is also best to use a level periodically throughout the process, preferably a long one. 

This is less critical if you are merely doing a light sanding, but if you are taking off a substantial amount of concrete or getting paint off the concrete, you want to make sure that you do so at an even level. 

4. Final Clean up Process

Although vacuuming throughout the sanding process is vital, you will not be able to do a truly thorough job until you are done blowing powder all over the place. 

So it is essential to do a long, complete vacuum job, hitting all of the nooks and crannies. 

After vacuuming, you will need to clean the floor to remove any remaining dust that the vacuum may have missed. 

This is best done by wiping the area with a piece of cheesecloth fabric. Alternatively, you can use paper towels or other dry towels. 

After cleaning, it is critical to cure or finish your concrete floor. 

There are many creative and interesting ways to do this, but that’s a story for another article.

Prevention and Upkeep of Your Sanded Concrete

The upkeep of your newly sanded concrete floor is critical, or it could need to be sanded again soon. 

The first and most crucial step is making sure that you properly seal your floor. 

After the floor has been sealed, you can stain or finish the floor, adding an extra layer of protection. 

After that, it is simply best to keep things away from your floor that could damage it. 

This includes tape adhesives, spilled paint, drywall mix, grease/oil, and water/moisture. 

What Else Can You Do with a Concrete Floor?

One alternative to having an exposed concrete floor is laying tile over the concrete. 

If doing this, it is still preferable to sand and/or level the concrete to the process described above, but it is not vital. 

Preparing the Concrete

At the very least, you must clean the concrete thoroughly using an acid-based cleaning product of your choice. 

Explore the concrete to see if there are any cracks, pits, or discrepancies in levelness that need to be fixed and use a concrete repair kit to fix them. 

After that, you need to let the concrete dry for a day.

After making sure that the concrete has been properly sealed, you are ready to start tiling. 

Beginning to Lay the Tile 

laying tiles on floor

To begin with, you need to plan the tile layout. This means measuring the space and the tiles, figuring out exactly how many tiles you will need, and if you will have to cut or resize any tiles. 

You can use chalk, string, or tape to mark the area. 

Then you need to fix a place to begin. Just like sanding a concrete floor, you should partition and work section by section. 

Also, like sanding a concrete floor, it is best to start with an area in a corner or near a wall. 

Once you have everything prepared, you will need to mix the mortar. 

The process of mixing mortar is relatively easy and straightforward, as long as you have the right recipe. 

Once your mortar is made, begin spreading it over a small area. 

Generally, I think it’s best to lay two tiles at a time, but there are differing thoughts on this. 

Be sure to use the correct spacers between your tiles and to make sure that the tiles are level with each other. 

This can take some getting used to, and it’s pretty common to have to lay a tile more than once. 

Be sure to keep the tiles clean throughout the process, getting all mortar off the top of the tiles before it dries. 

This makes the cleanup process in the end much easier. 

Next, after allowing the mortar to dry properly, it’s time to remove the spacers and fill them with grout.

 It is easiest to spread the grout evenly across the floor, making sure it gets into every empty crack. 

Once the grout is dry, wipe it clean with a wet rag. Once you are confident that it has fully cured, use a grout sealer to finish the job. 

Once the sealer itself has cured, clean up, and congratulate yourself. 


Can the Same Process Be Used to Sand Smaller Concrete Spaces, Such as Tables or Work Benches? 

Of course, there are some differences in sanding a large concrete floor and sanding a smaller area such as a table or bench, but the main process remains the same. 

However, I would highly recommend using hand sanding devices for smaller surfaces. 

This allows for more control and precision, which makes a difference cosmetically. 

And with a smaller surface, you don’t save so much time by going with a mechanical sander. 

How Long Will a Sanded Concrete Floor Last? 

There are many deciding factors to take into account when judging the lifespan of a new, sanded concrete floor. 

These include the expected foot traffic, maintenance, installation quality, and the environment and exposure (such as, inside or outside, etc).

That all being said, if properly installed and maintained, a sanded concrete floor should be able to last over fifteen years. 

Can You Paint or Color a Sanded Concrete Floor? 

concrete floor life span

Concrete floors do not have to all remain dull and grey.

Coloring and design options are nearly endless, some varying in the difficulty of installation. 

They can include different shades and styles of finish and different concrete friendly types of paint or stain. There is something for every taste. 

In Summary

Sanded concrete floors are becoming more and more in fashion for a reason. 

This is partially due to their practicality, and partially because they are relatively easy to create and maintain. 

But learning how to sand a concrete floor or space may seem like a daunting task. 

But it is not so difficult and can be accomplished by almost any do it yourself regular who is willing to put a little effort into it, whether they want to know how to sand concrete by hand or with a mechanical sander. 

Generally, figuring out how to sand down concrete is only a small part of a bigger project or one step in a series. 

Whether or not this is the final step in your process, you’re now on your way to completing a pretty special DIY flooring project.

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