What Drill Bit for Concrete — Complete Guide
Drilling concrete is fundamentally different from drilling brick. Concrete is denser, often reinforced with steel rebar, and requires either SDS Plus masonry bits (for light work) or SDS Max bits (for deeper holes and reinforced concrete). Never attempt concrete drilling without a proper masonry bit and hammer action.
This guide covers concrete types, which drill and bit combinations work, sizes, technique, and when to use core bits instead of standard masonry bits.
Concrete Types and Drilling Difficulty
Lightweight Concrete Block (Aircrete, Thermalite)
Hardness: Soft. Easy to drill.
Aggregate: Air pockets throughout (for insulation). Drills almost as easily as brick.
Best drill bit: Standard masonry bit (round shank or SDS Plus) with hammer action.
Speeds: 600–800 RPM with hammer on medium power.
Typical use: Modern house walls, partition walls, exterior leaf of cavity walls.
Dense Aggregate Concrete Block
Hardness: Medium. Harder than brick, tougher than lightweight block.
Aggregate: Dense sand and gravel. Few air pockets.
Best drill bit: SDS Plus masonry bit (preferred) or high-quality round shank masonry bit.
Speeds: 400–600 RPM with hammer on full power.
Typical use: Concrete blockwork, structural walls, older buildings.
Reinforced Concrete (Steel Rebar)
Hardness: Very hard. May contain steel reinforcement bars (rebar) that are extremely difficult to drill.
Aggregate: Cement, sand, gravel, and embedded steel rebar at 150–300mm intervals.
Best drill bit: SDS Plus for holes up to 20mm, SDS Max for larger holes or if rebar is present. Carbide-heavy or bimetal bits preferred.
Speeds: 300–400 RPM maximum. Go very slow if you hit rebar.
Typical use: Industrial floors, car parks, structural columns, older reinforced concrete buildings.
Challenge: If your bit hits rebar, you’ll feel sudden extreme resistance. Do NOT force it—pull back and try a few millimetres to the side. Hitting rebar can snap the bit or stall the motor.
Gunite or Shotcrete (Sprayed Concrete)
Hardness: Variable. Depends on age and curing time (can be very hard once fully cured).
Best drill bit: SDS Plus or SDS Max masonry bit, depending on depth and age.
Typical use: Swimming pool liners, tunnel repairs, structural reinforcement.
Polished or Decorative Concrete
Hardness: Very hard (often 50–60+ Brinell hardness).
Challenge: The dense surface coating makes drilling difficult. You risk chipping the finish.
Best approach: Use masking tape to prevent surface spalling, go slow (200–300 RPM), and use a high-carbide masonry bit or core bit.
Drill Type Requirements
Lightweight Concrete: Which Drills Work
Cordless drill-driver with hammer mode: Yes. A 18V hammer drill will handle lightweight block up to 10–16mm holes.
Corded hammer drill (650W+): Yes. Excellent choice for regular work.
SDS drill (600–900W): Yes. Professional choice. Superior for high-volume work.
Standard (non-percussion) drill: Not recommended. Too slow and inefficient.
Dense Concrete Block: Which Drills Work
Cordless hammer drill (18–20V): Marginal for holes over 10mm. Works but may stall if you hit hard aggregate.
Corded hammer drill (650–900W): Good. Will handle up to 16mm holes reliably.
SDS Plus drill (750–1000W): Best choice. Reliable up to 20mm.
Rotary hammer (SDS Plus or SDS Max): Excellent. Purpose-built for concrete.
Reinforced Concrete or Deep Holes (50mm+): Which Drills Work
SDS Plus drill: Adequate for holes to 20mm, but marginal for deeper work or if rebar is hit.
SDS Max rotary hammer (1200W+): Best choice. Much higher impact energy. Built for this work.
Core drill (wet coring bit): Best choice for very large holes (50–150mm) in reinforced concrete. Uses water cooling and carbide-matrix bit.
Corded hammer drill: Not recommended for reinforced concrete. Too weak.
Cordless tools: Not recommended for reinforced concrete. Battery power insufficient.
Masonry Bit Types for Concrete
Round Shank (6mm)
When to use: Lightweight block only. Small holes (up to 10mm).
Drill needed: Household hammer drill or cordless drill-driver with hammer mode.
Cost: £1–£2 per bit.
Limitations: Low torque transfer. The round shank can slip under heavy hammer impacts. Not ideal for dense concrete.
SDS Plus (10mm keyed shank)
When to use: Standard for lightweight to dense concrete block. Holes up to 20mm. Most common professional choice.
Drill needed: SDS Plus drill, rotary hammer, or high-end cordless SDS drill.
Cost: £2–£6 per bit.
Advantages: Secure keyed chuck (no slipping). High impact energy transfer. Widely available and standardised.
Amazon: SDS Plus masonry bit sets on Amazon
SDS Max (18mm keyed shank)
When to use: Reinforced concrete, deep holes (50mm+), rotary hammer work, professional demolition.
Drill needed: SDS Max rotary hammer only (1200W+).
Cost: £5–£15 per bit.
Advantages: Massive impact energy. Large diameter shank means no slipping even under extreme torque. Built for concrete drilling.
Amazon: SDS Max drill bits on Amazon
Carbide-Matrix Core Bits (for large holes)
When to use: Holes 50mm and larger in any concrete type. Also for reinforced concrete when you want to avoid rebar damage.
Drill needed: Wet core drilling machine or SDS Max rotary hammer (SDS Plus is too weak).
Cost: £15–£50+ depending on size.
Method: Uses water cooling and a carbide matrix (not individual teeth). Slower cutting but extremely durable.
Amazon: Core drill bits for concrete on Amazon
Common Concrete Drilling Sizes and Uses
| Hole Size | Typical Use | Best Bit Type | Drill Type |
|---|---|---|---|
| 5–6mm | Wall plugs, light fixings | Round shank or SDS Plus masonry | Hammer drill (any type) |
| 8–10mm | Heavy wall plugs, shelves | SDS Plus masonry | SDS drill or good cordless hammer drill |
| 12–16mm | Large anchors, cable runs | SDS Plus masonry | SDS Plus drill or rotary hammer |
| 20–25mm | Large pipes, major cable runs | SDS Plus or SDS Max | SDS Plus drill or SDS Max rotary hammer |
| 50mm+ | Large pipes, structural core samples | Core bit (carbide matrix) | Core drill machine or SDS Max rotary hammer |
Technique for Drilling Concrete
Before You Start
Check for utilities. Never drill without knowing what’s behind the concrete. Cable runs, water pipes, or electrical conduit could be embedded. Use a cable detector (£20–£50) if you’re unsure.
Mark your spot. Use a pencil or chalk. Use a centre punch to make a small indent so the bit doesn’t wander on initial contact.
Setting Up the Drill
Choose the right drill and bit. Match the concrete type to your equipment (see table above).
Insert the bit fully. For SDS Plus, push the bit into the chuck—it will click when locked. For round shank, tighten the chuck firmly with a key or by hand.
Select hammer mode. Most drills have a selector switch. Make sure you’re in percussion/hammer mode—not just rotation.
Set speed to low-medium. For lightweight block: 600–800 RPM. For dense block: 400–600 RPM. For reinforced concrete: 300–400 RPM maximum.
Drilling
Start gently. Position the bit at your marked spot. Squeeze the trigger lightly—don’t jam it in. The drill should gradually bite into the concrete.
Maintain steady pressure. Light to medium pressure works better than hard forcing. You’ll feel when the bit is progressing (steady vibration, dust spray). If you’re barely moving, you might be hitting a stone or rebar.
Withdraw periodically. Every few seconds, pull the bit back 1–2 cm (without turning off the drill) to clear concrete dust from the hole. A clogged hole causes friction and overheating.
Listen and feel. A healthy drilling sound is a steady “thump thump thump” from the hammer action. If the sound changes to a harsh “grind” or if the drill suddenly stalls, pull back immediately. You may have hit rebar.
What If You Hit Rebar?
You’ll know instantly—sudden extreme resistance, the drill might stall or jump. Do NOT force it.
Steps:
- Release the trigger immediately.
- Let the motor stop completely (don’t force it).
- Withdraw the drill slowly.
- Mark this spot and try drilling 5–10cm away.
- If you need to drill exactly here, consider a core bit with water cooling (slower, but it cuts through rebar).
Pro tip: Rebar usually runs in a grid pattern (150–300mm spacing) parallel to the surface. If you hit it, you know the next hole should be safe 200mm away in any direction.
Concrete Drilling Problems and Solutions
Problem: Bit won’t penetrate (feels like hitting solid rock)
Cause 1: You’ve hit an aggregate stone (perfectly normal). Try pulling back slightly and starting 1–2cm to the side.
Cause 2: You’ve hit rebar. See rebar section above.
Cause 3: Hammer mode is OFF. Check your drill’s selector switch.
Cause 4: The bit is worn or broken. Replace with a new bit.
Problem: Concrete spalling or chipping around the hole
Cause: Excessive pressure, high speed, or hitting near the edge of the concrete element.
Solution: Reduce pressure and speed. Use masking tape around the hole to reduce spalling. Mark holes carefully to stay away from edges.
Problem: Bit is smoking or discolouring (turning blue)
Cause: Overheating from excessive speed, lack of hammer action, or a clogged hole.
Solution: Stop immediately. Let the bit cool. Reduce speed to 300–400 RPM and check that hammer mode is ON. Clear clogged holes more frequently.
Problem: Drill keeps slipping or running off-centre
Cause: Round shank masonry bit slipping in the chuck (normal under extreme torque). SDS shank bent or chuck worn.
Solution: Tighten the chuck more firmly (for round shank). If using SDS Plus, check that the bit is fully seated. If persistent, the chuck may be damaged—consider upgrading to an SDS Plus drill.
Problem: Concrete debris is flying everywhere
Solution: Normal. Wear safety glasses and a dust mask. Concrete dust (silica) is dangerous if inhaled. Always wear respiratory protection when drilling concrete.
Concrete Drilling Safety
Wear safety glasses. Concrete shards and dust spray out at high speed.
Wear a dust mask or respirator. Concrete dust contains silica (SiO₂), which causes silicosis if inhaled. Use at least an FFP2 mask, or better yet, a powered respirator.
Secure the work. If drilling a small concrete block, clamp it down or have a helper hold it. The drill can twist your wrist if the bit suddenly binds.
Check for utilities. Always use a cable/utility detector before drilling into walls or floors. Hidden cables and pipes can cause electrocution or gas leaks.
Use two hands. Never drill one-handed. Keep both hands on the drill at all times.
Let the drill stop before withdrawing the bit. Never pull the bit out while the motor is still running—you risk jamming and twisting your wrist.
When to Use Core Bits Instead of Standard Masonry Bits
Use core bits (carbide matrix) if:
- Hole diameter is 50mm or larger
- Drilling through reinforced concrete and you want to avoid rebar
- Concrete is extremely hard (polished, industrial, or well-aged)
- You need very precise holes with clean edges (structural core samples)
Advantages of core bits:
- Extremely durable (can drill 100+ holes)
- Very clean edges (no spalling)
- Cuts through rebar without snapping (uses carbide matrix, not single teeth)
- Slower but more reliable for difficult jobs
Disadvantages of core bits:
- Require wet coring (water cooling) or SDS Max rotary hammer
- Slower than standard masonry bits
- More expensive (£15–£50+ per bit)
- Require specialised core drill equipment
Watch: Video Guide
Frequently Asked Questions
Can I drill concrete with a regular (non-hammer) drill?
Not effectively. Regular drills lack percussion power. You could slowly push through lightweight block with extreme pressure, but it would be extremely slow and frustrating. Always use hammer/percussion mode for concrete.
What if my hammer drill doesn’t have enough power for reinforced concrete?
Upgrade to an SDS Plus or SDS Max rotary hammer. These are purpose-built for concrete and deliver 5–10x the impact energy of a household hammer drill. For professional concrete work, SDS Max is the minimum.
How deep can I drill in concrete?
Practically, most masonry bits work well to 100–150mm depth. Deeper drilling becomes difficult because dust gets trapped in the hole. For holes deeper than 200mm, consider a core bit with water cooling or multiple short drills (clear the hole between each).
Why is concrete harder to drill than brick?
Brick is mostly clay fired to hardness. Concrete is cement-bonded aggregate with stones and sand throughout. The random stone distribution in concrete creates hard spots that bit harder than brick. Reinforced concrete adds steel rebar, which is extremely hard.
What’s the difference between SDS Plus and SDS Max?
SDS Plus: 10mm keyed shank. Good for light to medium concrete work, holes up to 20mm. Standard for most tradesmen.
SDS Max: 18mm keyed shank. For heavy-duty work, rotary hammers, holes 20mm+, reinforced concrete. Much higher impact energy.
Is silica dust from concrete dangerous?
Yes. Concrete dust contains crystalline silica (SiO₂), which causes silicosis when inhaled. This is a serious lung disease. Always wear a dust mask or respirator when drilling concrete. FFP2 masks are minimum; powered respirators are better.
Related Drill Bit Guides
- Drill bit compatibility guide (all shank types)
- What drill bit for brick and masonry
- What drill bit for ceramic and porcelain tiles
- What drill bit for metal and steel
er (1200W+).
Cost: £5–£15 per bit.
Advantages: Massive impact energy. Large diameter shank means no slipping even under extreme torque. Built for concrete drilling.
Amazon: SDS Max drill bits on Amazon
Carbide-Matrix Core Bits (for large holes)
When to use: Holes 50mm and larger in any concrete type. Also for reinforced concrete when you want to avoid rebar damage.
Drill needed: Wet core drilling machine or SDS Max rotary hammer (SDS Plus is too weak).
Cost: £15–£50+ depending on size.
Method: Uses water cooling and a carbide matrix (not individual teeth). Slower cutting but extremely durable.
Amazon: Core drill bits for concrete on Amazon
Common Concrete Drilling Sizes and Uses
| Hole Size | Typical Use | Best Bit Type | Drill Type |
|---|---|---|---|
| 5–6mm | Wall plugs, light fixings | Round shank or SDS Plus masonry | Hammer drill (any type) |
| 8–10mm | Heavy wall plugs, shelves | SDS Plus masonry | SDS drill or good cordless hammer drill |
| 12–16mm | Large anchors, cable runs | SDS Plus masonry | SDS Plus drill or rotary hammer |
| 20–25mm | Large pipes, major cable runs | SDS Plus or SDS Max | SDS Plus drill or SDS Max rotary hammer |
| 50mm+ | Large pipes, structural core samples | Core bit (carbide matrix) | Core drill machine or SDS Max rotary hammer |
Technique for Drilling Concrete
Before You Start
Check for utilities. Never drill without knowing what’s behind the concrete. Cable runs, water pipes, or electrical conduit could be embedded. Use a cable detector (£20–£50) if you’re unsure.
Mark your spot. Use a pencil or chalk. Use a centre punch to make a small indent so the bit doesn’t wander on initial contact.
Setting Up the Drill
Choose the right drill and bit. Match the concrete type to your equipment (see table above).
Insert the bit fully. For SDS Plus, push the bit into the chuck—it will click when locked. For round shank, tighten the chuck firmly with a key or by hand.
Select hammer mode. Most drills have a selector switch. Make sure you’re in percussion/hammer mode—not just rotation.
Set speed to low-medium. For lightweight block: 600–800 RPM. For dense block: 400–600 RPM. For reinforced concrete: 300–400 RPM maximum.
Drilling
Start gently. Position the bit at your marked spot. Squeeze the trigger lightly—don’t jam it in. The drill should gradually bite into the concrete.
Maintain steady pressure. Light to medium pressure works better than hard forcing. You’ll feel when the bit is progressing (steady vibration, dust spray). If you’re barely moving, you might be hitting a stone or rebar.
Withdraw periodically. Every few seconds, pull the bit back 1–2 cm (without turning off the drill) to clear concrete dust from the hole. A clogged hole causes friction and overheating.
Listen and feel. A healthy drilling sound is a steady “thump thump thump” from the hammer action. If the sound changes to a harsh “grind” or if the drill suddenly stalls, pull back immediately. You may have hit rebar.
What If You Hit Rebar?
You’ll know instantly—sudden extreme resistance, the drill might stall or jump. Do NOT force it.
Steps:
- Release the trigger immediately.
- Let the motor stop completely (don’t force it).
- Withdraw the drill slowly.
- Mark this spot and try drilling 5–10cm away.
- If you need to drill exactly here, consider a core bit with water cooling (slower, but it cuts through rebar).
Pro tip: Rebar usually runs in a grid pattern (150–300mm spacing) parallel to the surface. If you hit it, you know the next hole should be safe 200mm away in any direction.
Concrete Drilling Problems and Solutions
Problem: Bit won’t penetrate (feels like hitting solid rock)
Cause 1: You’ve hit an aggregate stone (perfectly normal). Try pulling back slightly and starting 1–2cm to the side.
Cause 2: You’ve hit rebar. See rebar section above.
Cause 3: Hammer mode is OFF. Check your drill’s selector switch.
Cause 4: The bit is worn or broken. Replace with a new bit.
Problem: Concrete spalling or chipping around the hole
Cause: Excessive pressure, high speed, or hitting near the edge of the concrete element.
Solution: Reduce pressure and speed. Use masking tape around the hole to reduce spalling. Mark holes carefully to stay away from edges.
Problem: Bit is smoking or discolouring (turning blue)
Cause: Overheating from excessive speed, lack of hammer action, or a clogged hole.
Solution: Stop immediately. Let the bit cool. Reduce speed to 300–400 RPM and check that hammer mode is ON. Clear clogged holes more frequently.
Problem: Drill keeps slipping or running off-centre
Cause: Round shank masonry bit slipping in the chuck (normal under extreme torque). SDS shank bent or chuck worn.
Solution: Tighten the chuck more firmly (for round shank). If using SDS Plus, check that the bit is fully seated. If persistent, the chuck may be damaged—consider upgrading to an SDS Plus drill.
Problem: Concrete debris is flying everywhere
Solution: Normal. Wear safety glasses and a dust mask. Concrete dust (silica) is dangerous if inhaled. Always wear respiratory protection when drilling concrete.
Concrete Drilling Safety
Wear safety glasses. Concrete shards and dust spray out at high speed.
Wear a dust mask or respirator. Concrete dust contains silica (SiO₂), which causes silicosis if inhaled. Use at least an FFP2 mask, or better yet, a powered respirator.
Secure the work. If drilling a small concrete block, clamp it down or have a helper hold it. The drill can twist your wrist if the bit suddenly binds.
Check for utilities. Always use a cable/utility detector before drilling into walls or floors. Hidden cables and pipes can cause electrocution or gas leaks.
Use two hands. Never drill one-handed. Keep both hands on the drill at all times.
Let the drill stop before withdrawing the bit. Never pull the bit out while the motor is still running—you risk jamming and twisting your wrist.
When to Use Core Bits Instead of Standard Masonry Bits
Use core bits (carbide matrix) if:
- Hole diameter is 50mm or larger
- Drilling through reinforced concrete and you want to avoid rebar
- Concrete is extremely hard (polished, industrial, or well-aged)
- You need very precise holes with clean edges (structural core samples)
Advantages of core bits:
- Extremely durable (can drill 100+ holes)
- Very clean edges (no spalling)
- Cuts through rebar without snapping (uses carbide matrix, not single teeth)
- Slower but more reliable for difficult jobs
Disadvantages of core bits:
- Require wet coring (water cooling) or SDS Max rotary hammer
- Slower than standard masonry bits
- More expensive (£15–£50+ per bit)
- Require specialised core drill equipment
Frequently Asked Questions
Can I drill concrete with a regular (non-hammer) drill?
Not effectively. Regular drills lack percussion power. You could slowly push through lightweight block with extreme pressure, but it would be extremely slow and frustrating. Always use hammer/percussion mode for concrete.
What if my hammer drill doesn’t have enough power for reinforced concrete?
Upgrade to an SDS Plus or SDS Max rotary hammer. These are purpose-built for concrete and deliver 5–10x the impact energy of a household hammer drill. For professional concrete work, SDS Max is the minimum.
How deep can I drill in concrete?
Practically, most masonry bits work well to 100–150mm depth. Deeper drilling becomes difficult because dust gets trapped in the hole. For holes deeper than 200mm, consider a core bit with water cooling or multiple short drills (clear the hole between each).
Why is concrete harder to drill than brick?
Brick is mostly clay fired to hardness. Concrete is cement-bonded aggregate with stones and sand throughout. The random stone distribution in concrete creates hard spots that bit harder than brick. Reinforced concrete adds steel rebar, which is extremely hard.
What’s the difference between SDS Plus and SDS Max?
SDS Plus: 10mm keyed shank. Good for light to medium concrete work, holes up to 20mm. Standard for most tradesmen.
SDS Max: 18mm keyed shank. For heavy-duty work, rotary hammers, holes 20mm+, reinforced concrete. Much higher impact energy.
Is silica dust from concrete dangerous?
Yes. Concrete dust contains crystalline silica (SiO₂), which causes silicosis when inhaled. This is a serious lung disease. Always wear a dust mask or respirator when drilling concrete. FFP2 masks are minimum; powered respirators are better.
Related Drill Bit Guides
- Drill bit compatibility guide (all shank types)
- What drill bit for brick and masonry
- What drill bit for ceramic and porcelain tiles
- What drill bit for metal and steel
t have hammer mode, consider investing in a hammer drill (£50–£300). For reinforced concrete, an SDS Plus or SDS Max rotary hammer is the professional choice.”
}
},
{
“@type”: “Question”,
“name”: “What should I do if my bit hits rebar?”,
“acceptedAnswer”: {
“@type”: “Answer”,
“text”: “You’ll feel sudden extreme resistance. Stop immediately—do NOT force it. Let the motor stop completely, then withdraw the drill slowly. Mark this spot and try drilling 5–10cm away. Rebar usually runs in a grid, so nearby holes should be clear.”
}
},
{
“@type”: “Question”,
“name”: “Why do I need a dust mask when drilling concrete?”,
“acceptedAnswer”: {
“@type”: “Answer”,
“text”: “Concrete dust contains crystalline silica (SiO₂), which causes silicosis if inhaled. This is a serious lung disease. Always wear at least an FFP2 dust mask, or better yet, a powered respirator. Never skip respiratory protection when drilling concrete.”
}
},
{
“@type”: “Question”,
“name”: “When should I use a core bit instead of a standard masonry bit?”,
“acceptedAnswer”: {
“@type”: “Answer”,
“text”: “Use core bits (carbide matrix) for holes 50mm and larger, or when drilling through reinforced concrete to avoid rebar. Core bits are slower but extremely durable and cut through rebar cleanly. They require wet coring equipment or an SDS Max rotary hammer.”
}
}
]
}
