How to Drill Through Concrete: Mastering the Art of Penetrating Stone

Concrete stands as humanity's most stubborn building material—a dense, unforgiving amalgamation of cement, sand, and aggregate that laughs at your average drill bit. Every weekend warrior who's tried hanging a heavy mirror in their basement or mounting a TV bracket to a concrete wall knows that peculiar moment of defeat when the drill bit simply stops, spinning uselessly against an impenetrable surface. It's a rite of passage, really, discovering that concrete demands respect and the right approach.

I've spent countless hours boring holes through concrete in various forms—from pristine poured foundations to century-old aggregate walls that seem harder than diamonds. Each type presents its own personality, its own challenges. What I've learned is that drilling through concrete isn't just about brute force or having the biggest, baddest drill. It's about understanding the material you're working with and approaching it with the right combination of tools, technique, and patience.

The Nature of Your Adversary

Concrete's strength comes from its crystalline structure, formed when cement hydrates and binds with aggregate materials. This process creates a matrix that's incredibly resistant to compression but, interestingly, somewhat vulnerable to the right kind of percussive force. The age of concrete matters tremendously—fresh concrete (less than a year old) tends to be more forgiving, while older concrete can be extraordinarily hard, especially if it contains certain types of aggregate like granite or quartzite.

I once worked on a 1920s building where the concrete was so hard that standard masonry bits would glow red-hot after just a few seconds of drilling. Turns out, the builders had used river rock aggregate that had been naturally polished and hardened over millennia. These kinds of surprises teach you humility quickly.

Essential Tools That Actually Work

Let me be blunt: your standard cordless drill isn't going to cut it for serious concrete work. You need a hammer drill at minimum, and for anything beyond occasional small holes, a rotary hammer is worth its weight in gold. The difference between these tools isn't just marketing speak—it's fundamental to how they attack concrete.

A hammer drill combines rotation with a rapid hammering action, typically delivering around 30,000 to 50,000 impacts per minute. Think of it as a tiny jackhammer that also spins. This dual action pulverizes the concrete while the rotation clears debris. Rotary hammers, on the other hand, use a piston mechanism that delivers fewer but much more powerful blows—usually around 4,000 to 5,000 per minute. The impact energy is measured in joules, and even a modest rotary hammer delivers exponentially more force than the best hammer drill.

For bits, carbide-tipped masonry bits are your entry-level option, suitable for occasional use in softer concrete. But if you're serious about the task, SDS (Slotted Drive System) or SDS-Plus bits are the way to go. These bits don't just drill; they're designed to withstand the hammering action without shattering. The carbide tips are brazed on differently, and the flute design is optimized for debris removal.

Technique: Where Finesse Meets Force

Starting a hole in concrete requires a different mindset than drilling wood or metal. Begin slowly, letting the bit establish a small crater before applying full power. This prevents the bit from walking across the surface, which is both frustrating and dangerous. I like to start at about half speed with light pressure, creating what I call a "pilot dimple."

Once you've got your starting point established, the real work begins. Apply steady, firm pressure—but not so much that you're leaning your full body weight into the drill. The hammer action does most of the work; your job is to guide it and maintain consistent pressure. Too much force actually slows the process and overheats the bit.

Here's something most people don't realize: concrete drilling is all about heat management. The friction generated can destroy a bit in seconds if you're not careful. Every 15-20 seconds of drilling, pull the bit completely out of the hole. This serves two purposes: it clears debris and allows the bit to cool. I've seen too many people try to power through in one go, only to end up with a bit that's lost its temper (literally—the heat ruins the carbide's hardness).

Dealing with Rebar: The Hidden Challenge

Nothing stops a drilling session faster than hitting rebar. That sudden, jarring halt followed by the screech of carbide on steel is unmistakable. Standard masonry bits can't cut rebar—they'll just spin against it, generating tremendous heat and accomplishing nothing.

You've got three options when you hit rebar. First, if the hole placement isn't critical, simply move over a few inches and try again. Second, if you must go through that exact spot, switch to a rebar-cutting bit. These specialized bits have a different carbide formulation and geometry designed to chew through steel. They're expensive and wear out quickly, but they work.

The third option, which I've used in desperate situations, is to use a standard metal-cutting bit to get through the rebar, then switch back to your masonry bit. This requires careful work to avoid damaging the metal bit on the surrounding concrete, but it's doable with patience.

Water: Your Secret Weapon

Professional concrete drillers often use water-cooled systems, and for good reason. Water dramatically extends bit life, reduces dust, and actually speeds up the drilling process. For DIY work, you can achieve similar benefits with a spray bottle and an assistant. Have them spray water into the hole every 30 seconds or so. The difference in bit life is remarkable—I've seen bits last five times longer with proper cooling.

The dust suppression benefit can't be overstated either. Concrete dust contains crystalline silica, which is seriously bad news for your lungs. Even with a good dust mask, reducing airborne particles is always preferable.

Anchoring: The Reason We're Here

Most concrete drilling is done to install anchors, and this is where precision matters. The hole must be the right diameter (check your anchor specifications—they're not suggestions) and deep enough to fully seat the anchor. I always drill about 1/2 inch deeper than the anchor length to accommodate dust that inevitably settles at the bottom.

Cleaning the hole properly is crucial for anchor strength. Compressed air works well, but in a pinch, a turkey baster or even vigorous brushing with a bottle brush can work. The goal is to remove all loose material that could prevent the anchor from achieving full holding power.

When Things Go Sideways

Sometimes, despite your best efforts, things don't go as planned. Bits break—usually when you're 3 inches into a 4-inch hole. When this happens, you'll need to extract the broken piece before continuing. I keep a set of needle-nose pliers and a magnetic retrieval tool specifically for this purpose. Sometimes you can drill alongside the broken bit with a smaller diameter bit to loosen it.

Concrete can also spall or chip around the hole entrance, especially in older or lower-quality concrete. To prevent this, start with a smaller pilot hole, or place a piece of duct tape over the drilling area. The tape helps hold the surface together during those critical first moments of drilling.

The Economics of Tool Choice

Here's where I might ruffle some feathers: for most homeowners, renting a rotary hammer makes more sense than buying a hammer drill. A decent hammer drill costs $150-300 and will struggle with harder concrete or larger holes. A professional-grade rotary hammer rents for about $50-75 per day and will make the job exponentially easier and faster.

I've watched too many people spend hours trying to drill a handful of holes with an underpowered tool, ruining multiple bits in the process. By the time you factor in the cost of replacement bits and your time, renting the right tool is actually the economical choice.

Final Thoughts from the Field

After years of drilling concrete in everything from modern high-rises to historical renovations, I've developed a deep respect for this material. It's unforgiving but predictable. It rewards preparation and punishes impatience. Every hole tells a story—about the concrete's composition, the skill of the person who poured it, and sometimes about the building's history.

The satisfaction of cleanly drilling through concrete, feeling that final breakthrough as the bit punches through the back side, never gets old. It's a small victory over one of humanity's toughest building materials, achieved not through brute force but through understanding, proper tools, and technique.

Remember, concrete drilling is one of those skills where the right approach makes the difference between a frustrating ordeal and a straightforward task. Take your time, use the right tools, keep everything cool, and always—always—wear safety glasses. Concrete chips have a nasty habit of finding eyes with uncanny accuracy.

Whether you're mounting a flat-screen TV, installing industrial equipment, or securing safety railings, the principles remain the same. Respect the material, use the right tools, and approach the task with patience and precision. The concrete will yield, but only on its terms.

Authoritative Sources:

Portland Cement Association. Design and Control of Concrete Mixtures. 15th ed., Portland Cement Association, 2011.

Mindess, Sidney, et al. Concrete. 2nd ed., Prentice Hall, 2003.

National Institute for Occupational Safety and Health. "Workplace Safety and Health Topics: Silica, Crystalline." Centers for Disease Control and Prevention, www.cdc.gov/niosh/topics/silica/.

American Concrete Institute. ACI 318-19: Building Code Requirements for Structural Concrete and Commentary. American Concrete Institute, 2019.

Occupational Safety and Health Administration. "Concrete and Masonry Construction." United States Department of Labor, www.osha.gov/concrete-masonry.