Two quick rules:
Brick, block & mortar → a masonry bit in a hammer/combi drill.
Concrete → an SDS bit in an SDS drill. Far less effort.
Turn the hammer (percussion) on, and match the bit size to your wall plug — a red plug takes a 6 mm bit.
Drilling masonry isn’t about a keen cutting edge like metal — it’s about hammering. A masonry or SDS bit has a tough tungsten-carbide (TCT) tip that pulverises the material while the drill’s hammer action pounds it forward. Get the right bit, the right drill and the right technique, and brick, block and concrete are straightforward. Here’s how.
Masonry bit vs SDS — what’s the difference?
| Masonry (TCT) bit | SDS bit | |
|---|---|---|
| Fits | Any standard 3-jaw chuck (round shank) | SDS-plus / SDS-max only — slots in, no chuck |
| Hammer action | The drill’s percussion (cam plates) — many light blows | A pneumatic piston — far fewer, far harder blows |
| Best for | Brick, block, mortar, soft stone | Concrete, dense masonry, reinforced concrete |
| Practical limit | Hard, hot going in real concrete; small–medium holes | Cuts concrete with ease; small to very large holes |
| Drill you need | Hammer drill or combi drill | SDS rotary hammer (SDS-plus) or SDS-max |
| Price | Lower | Bit is similar; the drill costs more |
A plain masonry bit will drill concrete in a combi drill — it’s just slow and hot going. For more than the odd hole in concrete, SDS pays for itself in effort saved.
Which bit for which material
- Brick, breeze/aircrete block, mortar — Profi Masonry Drill Bits in a hammer or combi drill. The everyday choice for plugs, fixings and rawlplugs.
- Dense or aggregate concrete, or a mixed wall (brick, block and mortar together) — step up to Extreme Concrete Drill Bits. Same tungsten tip as the Profi, but with an SDS-style spiral on a round shank — it clears dust and drills like an SDS bit, still in a standard hammer drill.
- Lots of holes, deep holes, or structural concrete — SDS Plus Concrete Drills in an SDS drill. This is where SDS earns its keep — it’s night-and-day easier than a combi drill.
- Big diameters (25 mm+) or breaking out — SDS Max Concrete Drill, plus SDS Chisels for chasing cable runs and removing tile or render.
- Tiles, glass or delicate finishes — a different job entirely: hammer off, a spear/tile bit, slow speed. (Our Drill Bit Finder covers tiles and glass.)
Wall plug & drill bit size
Match the drill bit to the plug, not the screw — the plug should be a firm push-fit in the hole.
| Plug colour | Masonry drill bit | Typical screw |
|---|---|---|
| Yellow | 5 mm | No. 4–8 (3.0–4.0 mm) |
| Red | 6 mm | No. 6–10 (3.5–5.0 mm) |
| Brown | 7 mm | No. 10–14 (4.0–6.0 mm) |
| Blue | 10 mm | No. 14–18 (6.5–8.0 mm) |
Plug colours aren’t a universal standard — a few brands differ, so check the pack. Rule of thumb: the drill bit matches the plug diameter, and the screw is 1–2 mm smaller than the plug.
How to drill it without wrecking the bit (or the wall)
When the bit just won’t go in
- You’ve hit rebar. In reinforced concrete a masonry or SDS bit won’t cut steel — it just spins and burns. Move over slightly, or switch to a bit rated to drill through reinforcing bar.
- Hard aggregate or flint. A combi drill stalls on it — this is exactly what SDS is for.
- Glazed tip, or hammer off. If progress stops, check you’re actually in hammer mode and the tip isn’t overheated and shiny.
Masonry, concrete and SDS — in stock, dispatched today
TCT masonry bits, extreme concrete bits, and the full SDS-plus and SDS-max range — single sizes or packs. Over a million bits in stock, free next-working-day UK delivery on orders over £50.
Frequently asked questions
Can I drill concrete without a hammer drill?
You can start a shallow hole in soft concrete with a masonry bit and patience, but a plain rotary drill has no hammer action, so it’s slow and hard on the bit. For anything more than a shallow hole, use a hammer or combi drill with a masonry bit, or an SDS drill for real concrete.
What’s the difference between a masonry bit and an SDS bit?
Both have a tungsten-carbide tip, but a masonry bit fits a normal 3-jaw chuck and relies on the drill’s light percussion, while an SDS bit slots into an SDS chuck and is driven by a pneumatic hammer that hits far harder. SDS makes short work of concrete; a masonry bit is fine for brick and block.
What size drill bit do I need for a red wall plug?
A 6 mm masonry bit. Match the bit to the plug (yellow 5 mm, red 6 mm, brown 7 mm), and drill to the depth of the plug plus a few millimetres.
Do I need SDS to drill brick?
No. A hammer or combi drill with a masonry bit handles brick, block and mortar easily. SDS is for concrete, dense masonry, deep holes and large diameters.
Why won’t my drill go into the concrete?
Usually one of three things: you’ve hit steel reinforcing bar (move over, or use a rebar-rated bit), you’re hitting hard aggregate that needs SDS, or the tip has overheated and glazed — check you’re in hammer mode and let it cool.
What’s the difference between a hammer drill and an SDS drill?
A hammer (combi) drill makes percussion mechanically with two ridged plates, giving lots of small blows. An SDS drill uses a pneumatic piston to deliver far fewer but much more powerful blows, so it drills concrete with a fraction of the effort.
UK Drills has supplied drill bits to UK trade and industry since 1985, from our trade counter in Hindley, Wigan. Not sure which bit for your wall? Email info@ukdrills.com — we’re happy to advise.
