How To Grind Down Concrete High Spots

Oct 7, 2021 | Concrete Tips, DIY Tips

Do you have a concrete floor full of high spots? Are you finding it uncomfortable to walk on such an uneven floor? Have you ever wondered about how you can grind down concrete high spots on your floor? Then wonder no more.

It’s always in your best interest to hire professionals for the job because it can get a bit complex. This doesn’t exactly mean that you can’t take on the job by yourself, no. However, you need to follow the right steps for grinding down concrete floor high spots.

In summary, here’s how to grind down concrete high spots:

  • Outline the space that needs to be ground, and then mark all the obvious high spots on your concrete using a piece of chalk.
  • Wear protective gear, including a face mask, gloves, and eye protection, and then start the grinder’s engine. Remember, you can get a concrete grinder from a nearby home center store, or you can simply rent one from a company that specializes in them.
  • Ensure that you lay the grinder’s disc flat against the high spots you’re planning to grind down. If you have the disc in place, start moving the grinder in a front to back or side to side motion until the high spot is ground to the floor level.
  • Repeat this process until the high spot is completely gone
  • Review your work and address any imperfections that might be there.
  • After you’ve ground all the spots you had marked using a piece of chalk, vacuum up the dust using a shop-vac.

How High Spots on a Concrete Floor are Removed

There is no denying that concrete is among the strongest and most durable building materials out there. This explains why many homeowners opt for concrete as their number one choice when it comes to flooring materials.

This can be attributed to the fact that concrete suits both modern and classic décor for both residential and commercial use. When concrete is well-polished, it can be the most beautiful aspect of any interior décor.

Additionally, such flooring can last for many years to come more than any other flooring material out there. However, this doesn’t mean that the concrete floor is without any flaws. For instance, in places where moisture accumulates a lot, such as the laundry room or basement, it’s not unusual for depressions to form even in the most expertly polished concrete floor.

Also, a concrete floor can also settle unevenly or develop cracks that can be both shallow and minor or deep and dangerous. Therefore, such imperfections need to be repaired early in advance.

By doing so, you’re preventing these imperfections from worsening and becoming major structural problems. On the other hand, if you’re planning on installing tiles, or hardwood, you need to ensure that you have a leveled surface. If any high spots don’t meet the standards, they have to be removed immediately.

Although this might sound so simple, that is not always the case. Removing high spots on your concrete floor requires great skills and high-quality equipment. Additionally, you also need to be ready to carry around hefty bags filled with concrete and equipment.

So, is there a cost-efficient way of removing these high spots from your concrete floor? Yes, there is. You can simply grind down high spots on your concrete floor using specialized grinding machines.

However, to get started with your concrete floor grinding project, you need to start by pouring water on the floor you’re planning to work on. This will help you find all the high spots that could hinder the project.

After finding them, you need to grind down these high spots using a wall-behind grinder, especially if they’re covering a large area. However, it’s very important to note that this heavy-duty grinder is usually fitted with diamond blades on the bottom.

Therefore, you need to know the exact moment to stop grinding because these blades cut so quickly. This explains why most people are mounting a laser receiver on their grinders. This is meant to alert the operator when it’s time to stop grinding so that they won’t end up digging too deep.

The best thing about this laser receiver is that it notifies you when the grinder has leveled the high spot so that you can move to another one. However, it’s important to understand that you’ll have to move the grinder up and down the stairs, especially if you’ll be working on your basement floor.

As far as the cost of grinding down concrete is concerned, most contractors usually charge about $1-$2 per square foot for a basic concrete floor with one layer of stain. On the other hand, contractors charge about $5-$8 per square foot for concrete floors with basic scoring and two colors. It will also cost you $8-$15 if your concrete floor has added design.

It’s important to understand that you can also use a terrazzo machine with Carborundum stones to remove high spots from your concrete floor. However, most people prefer diamond grinders because they’re much faster and efficient.

The Tools you’ll need for the Project

The tools you’ll require to remove high spots on a concrete floor will vary depending on the size of the area you’re working on. For example, if you’re planning on grinding high spots on a large concrete floor, you’ll need to use a walk-behind concrete grinder.

It’s preferable to rent this grinder from a company that specializes in them rather than purchasing it. When you rent it, you’ll be spending about $90-$150 every day. However, the good news is that with such a big machine, you’ll be able to grind through a large space within the rental period agreed upon.

Also, depending on the store you get it from and the machine it carries, you could be fortunate enough to get a diamond grinding wheel included in the rental agreement. If this is not the case, you might need to purchase your own diamond grinding inserts for about $150 a set.

On the other hand, if you’re working on smaller concrete floor space, it’s best to rent an angle grinder fitted with a diamond grinding wheel for about $50 a day or sometimes even less. The good thing about an angle grinder is that it is capable of grinding down a few high spots, which are located on tough to reach areas.

However, it’s very important that you ensure the angle grinder you rent is fitted with a vacuum for the sake of sucking up the dust. Alternatively, if you’re planning on grinding high spots up the wall, ensure that you rent an angle grinder fitted with a convertible dust shroud that will easily flip up to give the wheel enough room to get into the corner,

Ensure You Wear Safety Gear

Before embarking on such a project, it’s very important that you have your safety gear on. This includes items like hearing protection, a respirator, and safety glasses. You need to understand that the machines you’ll be working with are very loud and can easily send concrete rubble your way from the grinding wheel.

Additionally, grinding concrete floor means that fine silica will be released, and it is known to cause multiple health problems. To avoid such problems, ensure that you wear a NIOSH-certified N95-rated respirator.

However, before starting the job, you want to run a test to check the seal. For instance, if you can breathe in and out sharply without any air escaping, it means that the seal is good and you’re good to go.

On the other hand, if you have any facial hair, it can easily damage the seal. Therefore, ensure that you shave your facial hair before beginning the project.

Always Remember that Diamond Grains Do the Cutting

As you might have learned by now, the cutting surfaces of the grinders you’ll be using to grind down the high spots are basically diamond grains that are held together by segments. These segments are the raised metal parts you can easily see on the grinding wheel.

An aggressive grinding wheel, which is capable of taking down ¼ inch of concrete or even more, is known to grind away concrete faster but usually leaves a rougher surface. On the other hand, a less aggressive grinding wheel removes concrete materials slowly but leaves a smoother surface.

Before choosing the grinding wheel to use for your project, there is something you ought to consider. The more surface area the grinding wheel has, the less aggressive it will be. An aggressive grinding wheel is best suited for removing large high spots and rough areas of concrete.

Alternatively, a less aggressive grinding wheel is best suited for cleaning up tile-set residue from the concrete floor or wall or preparing for an epoxy coating.

Always Keep the Machine Moving

For your project to be successful, there are a few tricks you need to learn. For example, when you’re using a large concrete floor grinder, you need to keep the cutter head moving. You can simply do this by pivoting the grinding machine on its wheels while moving the cutter head in an arcing motion.

However, if the grinder’s cutting surface is only riding on one edge, it’s best to work the grinder in small circles. This will help you flatten out the high spots more easily.

How to Choose Dust Control

There are two main methods that can help contain the dust and prevent it from going wild all over the workspace. First, you can use a hand-pump sprayer and spray the concrete floor with water as you grind down the high spots to help keep the dust down.

However, the downside to this method is that in the end, you’ll have a messy slurry that you’ll need to suck up using a wet vacuum or simply hose it away. Second, you can opt to rent a heavy-duty vacuum to attach to the grinder.

It’s important to understand that regular shop vacuums will not be suitable for such a project. The best thing about a heavy-duty vacuum is that it will also get rid of the dust, but it will end up costing you $75.

You’ll also need to covers and walls of plastic sheeting near the vents. You’re the one to decide which method suits you the best. However, regardless of the method you opt for, ensure that you wear your respirator at all times.

Tilt the Grinder at a Heave

If you’re dealing with a heaved sidewalk or a wrecked slab, ensure you slant the grinder to a certain degree, remove the mass of concrete and then quill back the high spot. Even though you can not completely flatten all the toe-stubbing heaves, you can easily lessen the danger.

It’s also important to note that at this point, with the grinder tilted, the dust shroud won’t be able to catch all the dust. This means that you might need to get a second hose and someone to help you.

How to Grind Along the Edge

One rule you need to bear in mind when grinding high spots on your concrete floor is that you should never remove a residue cover/ dust shroud to get closer to the wall. This is because you’ll end up exposing yourself to nasty silica and getting rid of a safety barrier you might need.

In order to grind high spots near walls with a convertible dust shroud attached, you need to push the open end of the residue cover towards the divider and make some regular, shallow passes. However, while doing so, you need to ensure that you dint end up digging the edge of the wheel into the concrete floor as you move it back and forth.

Summing Up

A concrete floor grinding project is complex and involves a lot of safety measures. This means that you need to get everything in order before embarking on such a project. For example, you need to choose the right equipment for the project and ensure that everything is set up properly to avoid any accidents.

Therefore, a concrete floor grinding project requires you to devote your time and attention to it for the best results. However, if you don’t have the time for it or you’re unsure about your safety, it’s best to hire a reputed company to do the job for you.

The best thing about opting for a professional company is that they have the equipment and expertise required to grind all the high spots on your concrete floor just the way you want. Also, it might interest you to know that such a company also puts great measures in place in order to protect you and your property from debris and dust.