Drilling Into Concrete and Brick: Tools and Technique
How to drill into brick, block and concrete walls and lintels, covering drill type, bits, depth, dust, mortar joints and soft or old brick.
Brick and concrete are usually the best walls to fix into, because they hold plugs and heavy loads well. They are also the walls where the wrong tool takes forever and the wrong technique leaves a ragged hole. Here is what actually makes drilling masonry easier.
Use the right drill
- Hammer drill (SDS or percussion): hammering action makes light work of brick, block and concrete. An SDS drill is best for frequent or larger holes.
- Standard drill with hammer mode: fine for light work in brick, but slow in dense concrete.
- Cordless vs corded: cordless is convenient for small holes; corded gives steady power for larger ones.
A basic drill without hammer action will heat the bit and mark the wall without making much progress.
Choose the right bit
Masonry bits have a tungsten carbide tip. Use a bit size that matches your plug, and check the packet for the right diameter. SDS bits only fit SDS drills.
- Bit length: long enough for the plug and some extra depth for dust.
- Condition: blunt bits cause hot, slow drilling.
- Concrete: use a good-quality bit, as lower-quality ones wear quickly.
Know your wall
UK brick and block vary:
- Modern engineering bricks and dense concrete: very hard; take time and patience.
- Old soft bricks: can crumble or break out, especially near edges.
- Aerated concrete block (thermalite type): soft, with specific fixings needed.
- Hollow bricks and blocks: a void behind a thin outer layer, which needs fixings designed for it.
- Reinforced concrete lintels: steel bars inside may stop the drill. Move the position slightly.
Fixing shelves to plasterboard, brick and stud walls helps you identify the wall.
Technique
- Check for pipes and cables before drilling; see how to find studs, pipes and cables.
- Mark the spot and use masking tape or a depth stop on the bit.
- Start slowly to avoid skating across the plaster.
- Switch to hammer mode once the bit has started.
- Apply steady pressure, letting the drill do the work. Pushing very hard does not help.
- Withdraw the bit occasionally to clear dust, which stops it jamming and overheating.
- Drill to depth with a little spare room for dust.
- Clean the hole with a brush or vacuum before plugging.
Mortar joints and brick faces
Drilling into mortar is easier and does less damage to the brick, but mortar can be weak, particularly in old buildings. For light items it is sometimes a neat approach; for heavy loads, use the brick face itself. Try to stay away from brick edges, where they may split.
Protect yourself and your home
- Wear eye protection and a dust mask. Brick and concrete dust is harmful to breathe.
- Hold a vacuum nozzle near the hole to catch dust.
- Use dust sheets, particularly indoors.
- Ear defenders are wise, as hammer drills are loud.
When the bit will not go in
- Check hammer mode is on.
- Try a sharper bit or a different brand.
- You may have hit a steel reinforcement bar or a hard aggregate. Move over slightly.
- If it is too hard for your drill, an SDS machine may be the right answer, or ask a provider to take it on.
A worked example: fixing a shelf bracket into brick
Say you are fixing a heavy shelf bracket to a brick wall. Mark the hole through the bracket, then match a masonry bit to the plug (for a common red plug, a 6 mm bit; check the packet). Put tape on the bit at the depth of the plug plus a few millimetres to leave room for dust. Switch to hammer mode, drill at a steady speed, withdraw the bit now and then to clear dust, and stop at the tape. Blow or vacuum the hole, push in the plug and drive the screw. This takes a few minutes per hole once you have the rhythm.
Which drill mode, when
| Material | Mode | Notes |
|---|---|---|
| Soft brick, block | Hammer, lower speed | Easy to over-drill |
| Dense engineering brick | Hammer, firm pressure | Needs sharp bit |
| Concrete lintel | Hammer, SDS if available | Expect rebar contact |
| Mortar joint | Hammer, careful | Weaker hold, avoid for heavy loads |
Common mistakes
- Using a worn bit and pushing harder, which overheats and blunts it.
- Drilling too close to an edge or corner, so the brick splits.
- Skipping the dust clean-out, so the plug cannot seat.
- Forgetting eye protection and a dust mask.
- Not checking for pipes, flues or cables behind the brick.
Concrete in flats
Concrete ceilings and walls in blocks of flats may contain reinforcement or post-tensioned cables, and leases sometimes restrict drilling. Check with your management company before working into structural elements, and use a detector designed for concrete.
Frequently asked questions
Do I need a hammer drill for brick?
For a few holes in softer brick, a standard drill with hammer mode can cope. For concrete or many holes, an SDS or hammer drill saves time and effort.
How deep should I drill for a wall plug?
Slightly deeper than the plug length, so that dust has somewhere to go. The plug packet gives guidance on the right depth.
Why does the brick keep crumbling?
Old or soft brick can break out near edges. Move away from the edge, drill slowly, and consider longer plugs or a chemical fixing for heavy items.