Choosing the Right Drill Bits for Brick and Masonry

Choosing the right drill bit for brick or masonry can be the difference between a clean, professional job and a pile of dust, a ruined bit, and a messy hole. For UK homeowners and tradespeople, facing materials from soft red brick to dense, unforgiving engineering brick, the confusion is common. Using the wrong bit not only blunts it instantly but can also damage the drill’s motor and the wall surface.

This guide provides a clear, no-nonsense framework for identifying and selecting the correct masonry drill bit for any task. Learn how to match the bit to the material, the shank to the drill, and achieve clean, accurate holes every time.

Identifying the Correct Drill Bit for Brick and Masonry
Standard Carbide-Tipped Bits for Combi and Hammer Drills
SDS Plus Drill Bits: The Professional Choice for Heavy Masonry
Masonry Bit Comparison: Standard vs. SDS Plus
Specialist Bits for Engineering Bricks and Hard Stone
Essential Accessories & Consumables
Frequently Asked Questions

Identifying the Correct Drill Bit for Brick and Masonry

A masonry drill bit is specifically engineered to pulverise hard, brittle materials like brick, stone, and concrete, rather than cutting them like a wood or metal bit. Spotting one in a mixed toolbox is straightforward if you know what to look for.

The ‘Arrowhead’ Rule: The most obvious feature of a masonry bit is its tip. It has a distinct, spade-like or arrowhead shape, which is broader than the main shaft of the bit. This tip is made from an extremely hard material designed for impact.
Tungsten Carbide Tip: The arrowhead is made of tungsten carbide, a material far harder than the steel of the bit’s body. This is non-negotiable for drilling into masonry; a standard high-speed steel (HSS) bit will be destroyed in seconds against brick.
Wide Flutes: The spiral grooves (flutes) on a masonry bit are typically wider and deeper than on other bits. This design is crucial for efficiently clearing the large volume of heavy dust and debris created during drilling.

The Anatomy of a Masonry Bit

Understanding the parts of a masonry bit helps in choosing a quality tool. The tip’s geometry is designed to hammer and crush the material, which is then cleared by the flutes. The strength of the brazing—the weld that holds the carbide tip to the steel body—is a key indicator of quality. A weak braze will fail under the intense vibration of hammer drilling.

The shank is the end of the bit that fits into the drill’s chuck. The main types are:

Straight Shank: A simple cylinder, used in the three-jaw chuck of standard drills and combi drills.
Hex Shank: A six-sided shank that provides a more secure grip in a three-jaw chuck, reducing the chance of slipping under high torque.
SDS Shank: A specialised shank with slots and grooves that lock into an SDS (Slotted Drive System) drill. This system allows the bit to move back and forth independently for maximum hammer impact.

When to Reach for a Masonry Bit

A masonry bit is the only choice for drilling into common UK building materials like red clay bricks, concrete blocks, mortar, and most types of natural stone. It is essential to never use these bits on timber or plastic, as the pulverising action will tear and shred these materials, creating a very messy and inaccurate hole.

A useful trade tip is to always check the ‘feel’ of the surface before drilling. Start the drill slowly without the hammer function engaged to create a small pilot dimple. This prevents the bit from ‘walking’ across the face of the brick and ensures the final hole is exactly where it needs to be.

Standard Carbide-Tipped Bits for Combi and Hammer Drills

For most DIY tasks and light trade work, a standard masonry bit with a straight or hex shank is used in a combi drill set to its hammer-action mode. These are versatile and widely available, making them a staple in any toolkit.

How They Work: In a combi drill, the hammer action is created by a mechanical clutch mechanism that creates a high-frequency, lower-impact ‘chattering’ force. This works well for softer masonry.
The Heat Factor: Drilling generates immense heat. It’s crucial to periodically pull the bit out of the hole while drilling. This clears accumulated dust, which can clog the flutes, and allows the tip to cool, preventing it from losing its hardness.

How and When to Use Standard Bits

To use a standard masonry bit effectively, set the drill to the ‘hammer’ icon. Rotation alone will not be enough to penetrate the material. Speed control is vital; for harder materials, a slower, steady speed provides more control and reduces overheating. For softer blockwork, a faster speed can be more efficient.

As mentioned, starting the hole on a slow, rotary-only setting prevents the bit from wandering. Once a small indent is made, switch to hammer mode and increase the speed and pressure.

Choosing the Correct Diameter for Wall Plugs

One of the most common tasks is drilling for wall plugs, often known by the trade name ‘Rawlplugs’. Matching the bit size to the plug is critical for a secure fixing.

Common UK Sizes: The standard colour-coded system is well-established: yellow plugs typically use a 5mm bit, red plugs use a 6mm bit, and brown plugs use a 7mm or 8mm bit. Always check the packaging for the manufacturer’s recommendation.
Hole Accuracy: A hole that is even slightly too large will prevent the plug from expanding correctly, resulting in a weak fixing. Ensure the drill is held perpendicular to the wall.
Depth Control: To avoid drilling too deep, use the depth stop that comes with the drill. Alternatively, a simple and effective method is to wrap a piece of masking tape around the bit at the required depth.

Choosing the Right Drill Bits for Brick and Masonry

SDS Plus Drill Bits: The Professional Choice for Heavy Masonry

When facing hard concrete, dense engineering bricks, or needing to drill many holes quickly, professionals turn to SDS drills and bits. The Slotted Drive System (SDS) is a fundamentally different and more efficient mechanism for hammer drilling.

What is SDS? The system uses a specialised chuck that grips the bit’s slotted shank, allowing it to slide back and forth. The drill’s piston fires the bit forward like a small jackhammer, delivering far more impact energy directly to the tip than a combi drill’s clutch.
Speed and Power: The difference in performance is significant. An SDS drill can power through dense concrete in a fraction of the time it would take a combi drill, with far less effort from the user.
Essential for Hard Materials: For materials like reinforced concrete, granite, and the blue engineering bricks common in London and across the UK, an SDS drill is not a luxury—it’s a necessity.

2-Cutter vs. 4-Cutter Heads

SDS Plus bits are available with different head geometries, primarily 2-cutter or 4-cutter designs.

2-Cutter: The standard design, excellent for speed in brick and blockwork.
4-Cutter: Features a solid carbide tip with four cutting edges. This design produces a more perfectly round hole, which is crucial for setting chemical anchors and precision fixings. It also performs much better when encountering rebar (metal reinforcing bars) in concrete, as the design is less likely to jam or deflect.

A key tip for maintaining an SDS drill is to keep the bit shanks clean and apply a small amount of grease before inserting them. This lubricates the mechanism and extends the life of the drill’s chuck. Many professional brands like DeWalt and Makita offer high-performance SDS systems for demanding site work.

Masonry Bit Comparison: Standard vs. SDS Plus

Tool / Bit Type	Primary Use	When You Need It
Standard Masonry Bit	General purpose drilling in soft to medium-density masonry (brick, block, mortar).	For use in a combi drill for common DIY tasks like hanging pictures, shelves, or fitting small fixtures.
SDS Plus Drill Bit	High-speed, high-impact drilling in hard, dense materials (concrete, stone, engineering brick).	For use in an SDS drill for professional applications, drilling large diameter holes, or tackling very hard materials.

Specialist Bits for Engineering Bricks and Hard Stone

Some materials require more than even a standard SDS bit can offer. High-density materials can destroy lesser bits and require specific solutions.

Drilling into High-Density Materials

Class A or ‘Blue’ engineering bricks, common in civil projects and as damp-proof courses, are extremely dense and hard. Similarly, drilling into natural stone like granite or flint requires a specific approach.

While ‘Multi-Construction’ bits are excellent for drilling through mixed layers of material, they can struggle with prolonged use in these ultra-hard substances. If drilling produces sparks and makes little progress, the bit is either too soft or the drill speed is too high, causing the tip to overheat and fail.

For repetitive drilling in very hard materials, keeping a small cup of water to dip the bit tip into can help manage heat and prolong its life.

Large Diameter Holes with Core Drills

When a hole larger than about 20mm is needed for pipework or cabling, a standard drill bit is no longer the right tool. This is the job of a core drill. These are hollow, cylindrical bits that cut a circular channel, removing a solid ‘core’ of material.

TCT Cores: Tungsten Carbide Tipped cores are used with a powerful SDS drill on a low-speed, high-torque setting with hammer action. They are effective for brickwork and general masonry.
Diamond Cores: For reinforced concrete or very hard stone, a diamond core drill is required. These use diamond segments and operate with rotary action only (no hammer) and often with water to cool the bit and control dust.

It is always recommended to use a pilot drill first to ensure the core bit starts accurately and does not wander across the surface.

Essential Accessories & Consumables

Having the right accessories on hand ensures a smooth, safe, and professional job. Keeping these items in stock is a good practice for any regular DIYer or tradesperson.

Item	Use	Notes
Wall Plugs	Provide a secure anchor point for screws in masonry.	Stock a variety of common sizes (e.g., yellow, red, brown) to cover most jobs.
Safety Glasses	Protect eyes from flying dust and debris.	An absolute essential for any hammer drilling task.
Dust Mask	Prevents inhalation of harmful silica dust from brick and concrete.	Use an FFP3-rated mask for maximum protection.
SDS Shank Grease	Lubricates the chuck mechanism of an SDS drill.	A small tube lasts a long time and significantly prolongs tool life.

Frequently Asked Questions

What size drill bit is needed for red wall plugs?

Red wall plugs are a UK standard and almost always require a 6mm masonry drill bit. However, it is always best practice to confirm the required size on the plug’s packaging.

Can a masonry drill bit be used in a normal (non-hammer) drill?

While it is physically possible, it is highly ineffective. Without the hammer action to pulverise the material, the bit will spin uselessly and quickly overheat. A drill with a hammer function is essential for masonry.

Why is a masonry drill bit getting red hot and not drilling?

This happens when the tungsten carbide tip has been blunted or damaged, often from hitting a very hard object (like rebar) or from excessive heat. It can also occur if trying to drill a very hard material like an engineering brick without sufficient impact energy (e.g., with a standard combi drill). Once the tip is gone, the bit will no longer drill and must be replaced.

What is the difference between SDS and SDS Plus drill bits?

SDS Plus is the most common evolution of the original SDS system, featuring a 10mm diameter shank. There is also a larger SDS Max system (18mm shank) for heavy-duty demolition work. For most drilling tasks, SDS Plus is the professional standard. The terms are often used interchangeably, but SDS Plus is the correct modern term for this bit type.

How can someone tell if they have an engineering brick wall?

Engineering bricks in the UK are typically very dense, smooth-faced, and have a distinct colour—often a dark red/brown (Class B) or blue/purple (Class A). They make a sharp, high-pitched ‘clink’ sound when tapped with a hammer, unlike the dull thud of a standard house brick.