Concrete is drilled with a masonry bit in a hammer drill or rotary hammer, using firm pressure and a slow, steady pace while clearing dust from the hole. This is general guidance for light jobs such as small fixings; for anything structural, follow the maker’s manual, local codes and a qualified professional.
Know What You Are Working With
Concrete often hides steel reinforcing bars, pipes and electrical conduit. Hitting them can wreck a bit or cause real danger. Check building plans, use a detector made for the purpose and ask a professional if you cannot be sure what is inside. Avoid drilling near edges and corners, where concrete can break away.
Tools and Protection
- A hammer drill (or rotary hammer for larger holes) with hammer mode switched on.
- A masonry bit sized to match the plug or anchor. Read the anchor maker’s instructions for hole size and depth.
- Eye protection, a dust mask made for fine dust, and hearing protection.
- Tape or a depth stop to mark how deep to drill.
- A vacuum, brush or hand pump to clear dust.
The Steps
- Mark the hole with a pencil and a cross so the bit tip has a target.
- Set the depth. Wrap tape around the bit at the depth you need, adding a little for dust at the bottom.
- Fit the bit fully into the chuck and tighten it.
- Hold the drill with both hands, square to the surface. Begin at low speed to form a seat for the tip.
- Switch to a steady speed with firm, even pressure. Do not lean your whole weight on the drill; let the hammer action work.
- Pull the bit out partway every so often to clear dust. Packed dust slows the bit and heats it.
- Stop at the tape mark. Clean the hole thoroughly with a brush and a vacuum or pump before inserting a plug or anchor.
Common Problems
| Problem | Likely cause | What to try |
|---|---|---|
| Very slow progress | Dull bit or wrong bit type | Use a fresh masonry bit |
| Bit stops suddenly | Hit rebar or hard stone | Stop, move the hole slightly |
| Hole too wide | Wobbling drill | Hold square, use a side handle |
| Dust everywhere | Hole not cleared | Use a vacuum nozzle nearby |
If the bit hits metal, do not force it. Move to a new spot after checking what lies behind.
Hammer Drill, SDS and Rotary Hammer Compared
The tool you choose affects how easy it is to drill concrete and how long the job takes. A standard hammer drill combines rotation with a rapid back-and-forth action produced by clutch plates inside the tool. It is the common choice for occasional small holes in brick, block and concrete, and can also work as a normal drill when the hammer mode is switched off. Its impact energy is limited, so progress in hard concrete can be slow, particularly with larger bits.
SDS-type tools use a different bit holder and a piston mechanism that delivers stronger, more efficient blows. This is usually called a rotary hammer when the tool is designed for it. SDS tools drill larger holes in concrete more quickly and with less effort from the user, and many models can also chisel when set to hammer-only mode. They cost more and weigh more, and they need SDS bits rather than standard round-shank bits, which should be checked before buying accessories.
- Hammer drill: suits occasional small holes in masonry and general drilling.
- Rotary hammer with SDS: suits frequent or larger holes and dense concrete.
- Standard drill without hammer action: poor choice for solid concrete; it may be very slow and wear out bits.
- Cordless or corded: cordless is convenient but check the battery capacity; corded offers continuous power for bigger jobs.
Read the manual to see the maximum recommended hole size in concrete for your tool, and remember that the maker’s figures refer to specific conditions. If you plan many holes or large diameters, consider hiring or borrowing a rotary hammer rather than overworking a light drill.
Choosing and Caring for Masonry Bits
Masonry bits have a carbide tip brazed or inserted at the end of a steel body, which allows them to chip away concrete and stone. The tip shape and the flutes behind it affect speed and dust removal. Bits come in two main shank types: round or hex shanks for hammer drills with chucks, and SDS shanks for rotary hammers. Make sure the shank matches your tool, and check the bit’s rated working length and diameter against your needs.
Quality varies. A well-made masonry bit has a firmly attached carbide tip, clean flutes and a straight body. Cheap bits can have tips that chip or detach, and bodies that bend. If the bit wanders at the start, a short, stiff bit helps establish the hole, and a longer one can follow. Bits wear with use, and a dull bit generates heat and makes progress very slow. Never force a worn bit, as it can overheat and fail. Rotate it in and out of the hole to clear dust, and let it cool if it feels very hot to the touch with a gloved hand.
- Match the shank type to the chuck or SDS holder on your drill.
- Choose the diameter specified for your plug or anchor.
- Pick a length that allows the full depth plus clearance for dust.
- Replace bits with chipped tips, bent bodies or rounded edges.
- Do not use wood or metal bits in concrete, and avoid using masonry bits for steel.
Keep bits clean and dry, and store them in a case so the tips do not knock together. Check them before each use for damage.
Dust Control and Personal Protection
Drilling concrete produces fine dust that can contain silica and other particles harmful to the lungs. Dust levels can be high even when you only drill a few holes, particularly indoors. Control is better than relying only on a mask. Use a vacuum with a nozzle held close to the hole while you drill, or a drill attachment designed to catch dust at the source. Some rotary hammers offer integrated dust extraction systems that connect to a suitable vacuum. Check the vacuum’s filter rating for fine dust, and follow local guidance.
Wear a properly fitting respirator or dust mask rated for fine particles, eye protection and hearing protection. A loose-fitting mask or one made for sanding wood may not be adequate. Facial hair can affect the seal of some masks. Concrete dust is also an irritant to skin and eyes, so wear gloves where appropriate, though not when the manual advises against it for rotating tools. Cover floors and furniture or use drop sheets, and keep other people out of the area while you work.
- Capture dust at the source with a vacuum nozzle or dust shroud.
- Wear a respirator suited to fine dust, as local guidance indicates.
- Wear eye and hearing protection.
- Keep the work area ventilated and clear of bystanders.
- Clean up using a suitable vacuum rather than sweeping, which spreads dust.
If you drill concrete frequently or in enclosed spaces, workplace regulations may apply. Seek professional advice about dust management where required.
Drilling Technique for Holes That Hold
A well-drilled hole makes anchors hold better. Start by marking the position accurately and using a small pilot bit or a gentle start to prevent the bit from wandering. Hold the drill square to the surface, using the side handle with both hands. Let the hammer action do the work, and apply steady, moderate pressure rather than leaning on the tool. Too much pressure slows the hammer action and heats the bit, while too little makes the bit skate and glaze the surface.
Depth is important. Use a depth stop or a piece of tape on the bit to mark the depth, and add a little extra to allow dust to settle at the bottom without preventing the anchor from seating. Withdraw the bit periodically while it is still turning to clear dust from the hole, as the flutes bring it out. If drilling a hole near an edge, reduce the pressure to avoid breaking the concrete away, and keep the hole as far from the edge as the anchor maker advises.
- Check the hole diameter and depth against the anchor maker’s instructions.
- Drill straight; a skewed hole reduces holding power.
- Clean the hole thoroughly before inserting the anchor, using a brush and vacuum or a hand pump.
- Do not enlarge a hole by wobbling the bit, since oversized holes weaken the grip.
- If the hole is wrong, move to a new position rather than trying to fix a damaged one.
If the bit stops suddenly, switch off immediately, because you may have hit reinforcement. Do not force it. Move the hole slightly or consult a professional if the position is critical.
Budget Tiers, Questions to Ask and Signs of Wear
Tools for drilling concrete range from basic hammer drills to heavy-duty rotary hammers. Entry-level tools are fine for small, infrequent jobs, but they can struggle in dense concrete and take longer. Mid-range hammer drills and light SDS tools offer a good balance of power, weight and cost for homeowners and frequent users. Professional rotary hammers are built for repeated heavy use, with features such as vibration control, clutches that protect the user if the bit jams and dust extraction. Choosing the appropriate level depends on the number and size of holes you expect. For one-off projects, hiring can be more sensible than buying.
Questions to ask before buying or hiring:
- What maximum hole size in concrete does the maker give?
- Does the tool use SDS bits or round-shank bits?
- Does it have a side handle, depth stop and clutch protection?
- How heavy is it, and can I hold it comfortably in the positions I need?
- Is there an option for dust extraction?
- Are suitable bits and accessories easy to find?
Signs of wear include a drill that overheats, loses hammer action, produces unusual noises or smells, or has a chuck that no longer grips. Bits that make little progress, glaze or burn are probably worn out. Replace damaged cords and batteries, and have tools serviced by qualified people if necessary. Stop using any tool with a damaged guard, handle or switch. Follow the manual, wear protective equipment and seek professional guidance for structural or overhead work.
FAQ
Do I need a hammer drill?
For solid concrete, a hammer function makes the work far easier. A standard drill may be slow and wear out bits quickly.
Can I hang heavy items from concrete?
Weight limits depend on the anchor and the concrete. Follow the anchor maker’s instructions, and ask a qualified professional for load-bearing or overhead fixings.
What is the difference between a hammer drill and a rotary hammer?
A hammer drill uses clutch plates to create a light hammering action and takes round-shank bits. A rotary hammer uses a piston for stronger blows, usually with SDS bits, and drills concrete faster.
Can I drill concrete with a regular cordless drill?
For very light work in soft masonry it may be possible but slow, and the bit will wear quickly. A hammer drill is the more suitable tool for solid concrete.
Why is my masonry bit not making progress?
The bit may be dull, the wrong type, or the hammer mode may be off. Check the tool settings, clear dust and try a fresh bit before adding more pressure.
How do I avoid cracking the concrete near an edge?
Keep holes the distance from the edge that the anchor maker advises, start gently and reduce pressure. Avoid drilling too close to corners.
Is concrete dust really dangerous?
Fine dust from concrete can harm the lungs and irritate the eyes and skin. Control it at the source, wear a suitable respirator and follow local guidance.
How can I check for rebar before drilling?
Use a detector designed for the purpose, consult building plans and ask a professional if unsure. If the bit stops suddenly, stop and move the hole.
Why must the hole be cleaned before inserting an anchor?
Dust in the hole prevents the anchor from seating fully and reduces its grip. Follow the anchor maker's instructions for cleaning methods.
The Short Version
Check for hidden hazards, use a masonry bit in hammer mode, drill square and steady, and clear dust often. Wear eye, ear and dust protection, and get professional help for structural work.