Drilling into concrete looks simple until the bit skids across the surface, smokes, or snaps halfway through. Concrete is one of the hardest common building materials, and an ordinary wood or metal bit will not get through it. The job becomes manageable once you understand what makes concrete different: it is a composite of cement paste, sand, and stone aggregate that resists steady cutting but responds well to hammering. Success comes down to choosing drill bits and mastering masonry techniques before the drill ever touches the wall.
A hammer drill, a carbide-tipped masonry bit, and a few safety items cover most residential jobs. The same fundamentals apply whether you are hanging a picture or anchoring a fence post to a slab.
Choose a Drill That Can Handle Concrete
A standard drill spins but does not hammer, and rotation alone cannot break through concrete. The minimum tool for the job is a hammer drill, which adds a rapid pounding action to the spinning bit. Each blow fractures the aggregate at the tip while the flutes pull dust out of the hole.
Hammer Drill vs. Rotary Hammer
Hammer drills suit holes up to about 13 mm, or half an inch, in normal residential concrete. Rotary hammers are heavier machines that use a piston mechanism to deliver far more impact energy, and they excel at holes from 13 mm up to 50 mm as well as at drilling through reinforced concrete. Choose a hammer drill for shelves, pictures, and light anchors, and step up to a rotary hammer for large anchors or long sessions.
Cordless hammer drill considerations
Cordless hammer drills have improved enough that a good 18 V model handles most home jobs, but battery power drains fast in hammer mode. Keep a second battery charged and expect roughly a third less runtime than in standard mode. For a larger project such as drilling a dozen anchor holes in a concrete wall, a corded drill avoids the mid-job battery swap.
When you compare models, look for these features:
- A two-speed gearbox, so you can start slowly and speed up once the hole is established
- A side handle, because a bit that grabs can twist the drill body sharply
- A depth stop or a tape marker to control hole depth
- An adjustable clutch for the drilling and screwdriving tasks
Research has also changed how crews drill. A UC Berkeley project tested drilling methods and produced a simpler, repeatable technique that reduces bit wander and operator fatigue, giving contractors and homeowners a safer and faster way to drill concrete.
Pick the Right Drill Bit for Concrete
The bit does the actual cutting, and the wrong bit fails within seconds. Masonry bits are the standard choice: their carbide tip stays sharp against aggregate while the steel body absorbs the hammer blows. A bit marked for masonry, concrete, or brick is what you need; wood and metal bits fail fast.
Masonry bit geometry
Masonry bits look similar to wood bits but differ in the tip. The carbide cutting edge is wider and flatter, and the shank is strengthened to survive hammering. For hammer drills with SDS-plus chucks, the bit slides in without a key; for standard three-jaw chucks, a round shank works but can slip under heavy pressure.
SDS-plus vs. round shank bits
SDS-plus bits lock into the chuck with grooves and do not slip under hammering, which makes them the first choice for rotary hammers. Round-shank masonry bits fit ordinary hammer drills but transfer less impact energy. Buy bits whose shank matches the chuck you already own.
Diameter matters as much as type. The bit should match the anchor or screw you plan to install: a 6 mm bit for a 6 mm wall plug, an 8 mm bit for heavy shelf brackets. Shank length sets how deep you can go, and effective drilling depth is bit length minus the length held by the chuck.
| Bit diameter | Typical anchor or screw | Common use |
|---|---|---|
| 5 mm | Small wall plugs | Picture hooks, cable clips |
| 6 mm | 6 mm plugs, light screws | Shelves, curtain rails |
| 8 mm | 8 mm plugs, sleeve anchors | Heavy shelves, brackets |
| 10 mm and up | Wedge anchors, threaded rod | TV mounts, handrails, machinery |
Drilling performance also depends on the concrete itself. Fresh concrete with high moisture content drills differently from cured concrete, and concrete strength and porosity change how much effort each hole takes. Dense, low-porosity concrete from a high-strength mix slows every bit, so budget extra time for driveways and precast elements.
Prepare the Surface Before Drilling
A clean surface makes a cleaner hole. Sweep or vacuum the area, mark the location with pencil or chalk, and check both sides of the wall when you can.
Locate rebar and hidden services
Steel reinforcement hides inside most structural concrete. Hitting rebar with a masonry bit dulls the carbide instantly and can stop the hole completely. A stud finder with metal detection mode or a dedicated rebar locator maps the steel before you drill. Trace utilities before drilling starts.
If the surface is tiled or finished, the approach changes. Decorative surfaces such as colorful concrete tiles need a slow start so the bit does not skate across the glaze, and drilling over a tile joint is easier than through the middle of a tile. The same caution applies to polished concrete floors.
Mark the hole and protect the edge
Tape over the marked spot gives the bit a purchase point and keeps the surface from chipping. For walls, mark the exact height; for floors, mark the center point. A pilot dimple made with a center punch stops the bit from wandering on first contact.
Drill the Hole Step by Step
Drilling is a sequence of small steps, and skipping any of them produces a bad hole. Follow this order on every concrete surface:
- Fit the correct masonry bit and set the drill to hammer mode.
- Start at low speed and let the bit find its own path; do not lean on the drill.
- Drill a pilot hole about 3 mm smaller than the final bit.
- Switch to the final bit and increase speed, keeping the drill perpendicular.
- Pull the bit out every 10 to 15 seconds to clear dust.
- Stop when the depth mark reaches the surface, then withdraw the bit while it spins.
Pilot hole technique
A pilot hole is a shallow, smaller-diameter hole that guides the final bit, reduces wander, and confirms the location before you commit to the full diameter. Drill the pilot 10 to 20 mm deep, then follow with the full-size bit.
Speed and pressure control
Run the drill slowly until the carbide has a bite, then speed up. Firm, steady pressure beats force: pushing hard heats and dulls the bit, while the hammer action does the cutting. If the bit stops advancing and the drill smells hot, stop, pull out, and clear the dust.
Dust removal is the hidden half of the job. Concrete dust packs into the flutes and locks the bit in place, which is why the hole seems to stop progressing. Withdraw the bit every few seconds, or use a small vacuum at the hole mouth, to keep the cutting edge in contact with fresh material.
Concrete condition affects drilling as well. Fresh pours need curing time before they take anchors, and poorly compacted sections can crumble at the hole edge. Understanding how to consolidate concrete in congested reinforced members helps you recognize sound concrete from honeycombed areas, so you can pick a solid spot for the anchor.
Common Drilling Problems and Fixes
Most drilling problems trace back to the bit, the speed, or the material. A smoking bit is dull or too fast, a wandering hole means the start was rushed, and a binding drill means dust has packed the flutes.
Bit binding and overheating
Binding happens when the bit jams in the hole, usually from dust packing or from hitting aggregate at an angle. Stop the drill immediately, reverse it briefly to clear the flutes, and restart at a lower speed. Overheating shows as blue discoloration and a burnt smell; let the bit cool before continuing.
Drilling into blocks and hollow sections
Not every wall you drill is solid concrete. Masonry block walls can be hollow behind the face, and the approach changes with the material. Knowing the difference between hollow concrete blocks and solid concrete blocks tells you whether a standard wall plug will grip or whether you need a hollow-wall anchor or an epoxy-set rod.
Other materials behave differently too. Brick drills quickly but chips easily at the exit face. Mortar joints accept anchors readily but carry less load. Tile needs a slow start and a carbide-tipped tile bit.
Install Anchors and Finish the Job
A drilled hole is only as useful as the anchor that fills it. Blow the dust out of the hole completely, then insert the wall plug, anchor, or screw that matches the hole diameter. Tap the plug flush with a hammer to seat it without crushing the rim.
Match the anchor to the load
Light loads such as pictures need a simple wall plug and screw. Medium loads such as shelves need a deeper plug or a metal anchor. Heavy loads such as TV brackets and handrails need expansion anchors or epoxy-set threaded rod rated for the expected force.
- Nylon wall plugs for light and medium loads in solid concrete
- Sleeve anchors for medium loads, available in zinc and stainless steel
- Wedge anchors for heavy loads, expanding at the bottom of the hole
- Epoxy-set threaded rod for the highest loads or holes close to a concrete edge
Screws made for concrete cut their own threads in a pilot hole. Do not hammer them in; drive them at low speed and stop before the head sinks below the surface. An old, spalled surface may need resurfacing before it can hold anchors, and the rules for pouring new concrete over an old concrete surface decide whether the patch bonds or delaminates.
After the anchors are in, check the work. The screw should feel solid when you tug it, and the plug should not rotate in the hole. If the concrete around the hole crumbled during drilling, move the anchor or repair the damage before relying on it. Routine post-concrete inspection and testing catches small defects before they become structural problems, which is why professional crews verify their concrete work the same way they verify their drilling.