What will an angle grinder do to concrete?

You have an uneven concrete slab that’s a tripping hazard, or a rough surface that needs to be prepped for flooring. Using a heavy, expensive machine seems like overkill for a small job. Can a simple angle grinder handle a material as tough as concrete?

An angle grinder, when fitted with the correct diamond abrasive wheel, will effectively cut, grind, and smooth concrete. It is a powerful and versatile tool for surface preparation, leveling high spots, and creating clean edges, but it requires the right accessory to work safely and efficiently.

At our company, Reliable, we manufacture abrasives for every application. We know that a power tool is only as good as the blade or wheel attached to it. While an angle grinder¹ is just a high-speed motor, pairing it with one of our specialized diamond wheels transforms it into a concrete-shaping machine. Concrete is incredibly hard and abrasive, and only the hardest material on earth—diamond—can effectively wear it down without being destroyed in the process. Understanding how to use this combination correctly is the key to mastering small-scale concrete work.

Can an angle grinder be used on concrete?

You have an angle grinder and a concrete problem. But the standard metal-cutting wheels you own seem completely wrong for the job. Are you missing a key piece of the puzzle?

Yes, an angle grinder is one of the best handheld tools for concrete, but only if you use a diamond blade for cutting or a diamond cup wheel for grinding. A standard abrasive wheel for metal will disintegrate without affecting the concrete.

The secret is the abrasive material. Concrete is a composite of sand, aggregate (rocks), and cement. Standard abrasive wheels², like the aluminum oxide ones we make for steel, are simply not hard enough to handle the aggregate. They will wear down in seconds, creating a lot of dust and no progress. This is why we developed a specific line of diamond tools³. Diamond is significantly harder than the components of concrete. Our diamond cup wheel⁴s have metal segments with industrial diamond crystals embedded in them. As the wheel spins, these diamonds scratch and pulverize the concrete surface. Diamond cutting blades work similarly but are thin for making precise cuts. Using anything other than a diamond abrasive on concrete is a waste of time and money.

Diamond Attachments for Concrete

Can you grind concrete to make it smooth?

Your concrete floor is rough, bumpy, and full of imperfections. This makes it impossible to lay down tile or simply have a clean, usable surface. How can you get it perfectly smooth?

Yes, you can grind concrete very smooth with an angle grinder by using diamond cup wheels in successive stages. You start with a coarse-grit wheel to level the surface and remove major bumps, then switch to a finer-grit wheel to erase the initial grind marks.

The process is very similar to sanding wood. You don’t start with fine-grit sandpaper on a rough board. The same logic applies to concrete. You must begin with an aggressive, coarse-grit diamond cup wheel (for example, a 30-grit). This wheel will do the heavy lifting, quickly grinding down high spots and creating a level plane. This first pass will leave a very clean but rough texture. Once the area is level, you switch to a finer-grit wheel, such as a 60- or 100-grit. This second pass will remove the scratch pattern left by the coarse wheel, resulting in a much smoother finish that is ready for most coatings or floorings. Crucially, always use a dust shroud⁵ attachment on your grinder connected to a vacuum. Concrete dust contains silica, which is extremely hazardous to breathe.

The Concrete Grinding Process

1. Safety First: Put on your P100 respirator, safety glasses, and gloves. Attach a dust shroud and vacuum to the grinder.
2. Coarse Grind: Use a low-grit (30/40) diamond cup wheel to level the entire surface and remove any coatings or high spots.
3. Fine Grind: Clean the surface. Switch to a higher-grit (80/100+) diamond cup wheel to smooth out the scratches from the first pass.

What cannot be cut with an angle grinder?

An angle grinder is so powerful and versatile that it feels like it could cut through anything. This assumption is not just wrong; it can be extremely dangerous if you try to cut the wrong material.

Never use an angle grinder with a standard cutoff wheel to cut wood, as it will grab and kick back violently. It is also the wrong tool for glass, which will shatter. Furthermore, it’s not practical or safe for cutting very thick structural steel.

A tool’s power can create a false sense of capability. As a manufacturer, we have to be clear about a tool’s limitations to ensure safety. Wood is the biggest danger. An abrasive wheel doesn’t saw wood; it burns and clogs, leading to a fierce kickback⁶. Always use a saw for wood. Glass is another clear "no." The vibration and aggressive action of an angle grinder will instantly shatter a pane of glass into dangerous, flying shards. Glass is cut by scoring a line and snapping it. Finally, while an angle grinder excels at cutting thin metal like rebar or sheet metal, it is not the right tool for thick structural steel like an I-beam. It would be incredibly slow, consume many wheels, and create a significant safety risk if the wheel gets pinched deep in the cut.

How much concrete can an angle grinder remove?

You need to lower a concrete surface by a full inch. An angle grinder with a diamond wheel seems like the obvious tool, but will it be effective, or will you be there for days?

An angle grinder is a surface preparation tool, not a bulk removal tool. It excels at removing up to about 1/8 to 1/4 inch (3-6 mm) of concrete. For removing an inch or more, you need a much larger, more specialized machine.

Matching the tool to the scale of the job is critical for efficiency and safety. An angle grinder is the perfect choice for detail work. Use it to grind down a high spot, smooth out a small patch, remove an old paint or epoxy coating, or clean up the edges of a larger room. It offers precision and control. However, if your task is to lower an entire garage floor by an inch, an angle grinder is the wrong tool. It would be painstakingly slow and put immense strain on the tool and the operator. For that scale of work, professionals use dedicated walk-behind concrete grinders or even heavy-duty concrete planer⁷s or scabblers, which are designed to remove thick layers of material quickly over large areas.

Choosing the Right Concrete Removal Tool

Conclusion

An angle grinder is an excellent tool for cutting and smoothing concrete when paired with the right diamond wheel. It is essential for surface prep, but not for bulk removal, and requires proper safety gear.