Masonry Fixings Guide — Wall Plugs for Brick, Block & Concrete
Masonry walls — brick, concrete block, stone, and poured concrete — are the strongest wall types to fix into, but only if you use the right plug, drill bit, and technique. This guide covers standard expansion wall plugs, frame fixings, resin anchors, and when to use each type for solid masonry walls.
Quick Answer
For most masonry fixings, standard colour-coded expansion wall plugs are all you need. Use a red (6mm) plug for general-purpose jobs, brown (7mm) for heavy loads, and blue (10mm) for structural fixings. Always match the drill bit to the plug diameter and drill on hammer mode for hard masonry.
Types of Masonry Fixings
1. Standard Expansion Wall Plugs
The most common masonry fixing. A plastic plug is inserted into a drilled hole, then a screw is driven in which forces the plug to expand and grip the sides of the hole. Available in all standard colours (yellow through blue) for loads from a few kilograms to over 100kg per fixing.
Best for: 90% of domestic fixing jobs — shelves, brackets, rails, cabinets, TV mounts.
2. Universal Plugs (e.g., Fischer DuoPower)
Universal plugs are designed to work in any wall type — solid masonry, hollow masonry (like perforated engineering bricks), and plasterboard. In solid masonry, they expand like a standard plug. In hollow materials, they fold and knot behind the material. They’re ideal when you’re unsure what’s behind the plaster.
Best for: Mixed wall types, unknown wall construction, cavity-brick walls.
3. Frame Fixings (Hammer Fixings)
Frame fixings are long, thin fixings used to attach timber frames, window frames, door frames, and battens directly to masonry. They’re driven through the frame and into the masonry in one action — drill through both, insert the fixing, and hammer or screw home. Typical sizes are 8mm x 80mm to 10mm x 160mm.
Best for: Window frames, door frames, timber battens, stud framing against masonry.
4. Resin Anchors (Chemical Fixings)
Resin anchors use a two-part chemical adhesive (typically polyester or epoxy) injected into a drilled hole. A threaded rod or bolt is then inserted into the resin, which sets hard in minutes and creates an extremely strong bond. They’re essential for hollow or soft masonry where expansion plugs can’t get a grip.
Best for: Aerated block (Thermalite), perforated brick, crumbly mortar, structural fixings, heavy loads in poor masonry.
5. Anchor Bolts (Sleeve Anchors / Wedge Anchors)
Heavy-duty metal anchors that expand mechanically when tightened. They’re designed for concrete and hard masonry and provide very high holding power. Common in commercial and industrial settings, but also used domestically for fixing steel brackets, base plates, and heavy structural items.
Best for: Concrete floors/walls, steel-to-concrete connections, structural brackets, heavy machinery.
Masonry Fixing Comparison
| Fixing Type | Wall Types | Load Capacity | Removable? | Cost |
|---|---|---|---|---|
| Standard wall plug | Solid brick, block, concrete | Up to 100kg+ | Yes | £ |
| Universal plug | Any masonry + plasterboard | Up to 60kg | Yes | ££ |
| Frame fixing | Solid masonry | Moderate–high | Difficult | ££ |
| Resin anchor | Any masonry (esp. hollow/soft) | Very high | No (permanent) | £££ |
| Anchor bolt | Concrete, hard masonry | Very high | Difficult | £££ |
Fixing Into Different Masonry Types
Hard Engineering Brick
Dense, strong brick found in older properties and engineering applications. Standard wall plugs work extremely well. Use hammer drill mode with a masonry bit. These bricks are hard to drill — expect slower progress and keep the bit cool by pausing periodically.
Standard House Brick
The most common wall type in UK homes. Standard wall plugs in any colour provide excellent holding power. Use hammer drill mode. Drill into the brick face rather than the mortar joint for the strongest fix.
Concrete Block (Dense)
Solid concrete blocks used in newer builds. Standard wall plugs work well. Similar to brick — use hammer drill mode and match the drill bit to the plug colour.
Aerated Block (Thermalite / Celcon)
Special Care Needed
Aerated blocks are soft and crumbly. Standard wall plugs often fail because the block can’t resist the expansion force. For light loads, use longer plugs. For heavy loads, use resin anchors or specialist fixings like Fischer Thermax. Never use hammer drill mode — rotation only.
Stone Walls
Natural stone varies enormously in hardness. Hard granite or sandstone takes standard wall plugs well (use a quality masonry bit and expect slow progress). Soft limestone or crumbly stone may need longer plugs or resin anchors. Irregular stone surfaces may need shimming or packing before fixing.
Poured Concrete
Very hard and dense. Use a quality SDS+ hammer drill for larger holes. Standard wall plugs and anchor bolts both work well. Concrete gives the highest holding capacity of any masonry type.
Common Mistakes with Masonry Fixings
Avoid These Mistakes
Drilling into mortar instead of brick — mortar is weaker and may crumble. Using hammer drill in soft block — pulverises the hole. Not cleaning dust from the hole — dust reduces plug grip by up to 50%. Undersized plug — always go up a size rather than down if in doubt. Drilling through a pipe or cable — always check with a detector before drilling.
Recommended Masonry Fixings
| Product | Type | Best For | Link |
|---|---|---|---|
| Fischer SX 6mm Red Wall Plugs (50 Pack) | Standard expansion | General-purpose masonry | View on Amazon |
| Fischer DuoPower 6x30mm (100 Pack) | Universal | Any wall type | View on Amazon |
| Rawlplug Mixed Wall Plug Kit (272 Pieces) | Assorted standard plugs | All-in-one for most jobs | View on Amazon |
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