Wall plugs are plastic inserts designed to grip a screw inside a pre-drilled hole in solid masonry. They work well for light to medium loads in brick, block or concrete. Anchors are a step up: they are used where higher load capacity is needed, or where the substrate is hollow, soft or prone to crumbling. Sleeve anchors, for example, expand mechanically within the hole to create a much stronger fixing than a standard plug. For hollow walls such as plasterboard, specific hollow wall anchors or toggle-style fixings are needed instead.
Anchor Fixings for Masonry, Concrete and Hollow Walls
Anchors are the go-to fixing when a standard screw or plug simply won't hold. MacBlair stocks a range of anchor fixings suited to solid substrates like concrete, brick and blockwork, as well as hollow wall applications. Whether the job calls for a sleeve anchor in dense masonry or a frame-style fixing through a cavity, getting the anchor type right matters far more than most people expect.
Choosing the correct anchor depends on three things: what you're fixing into, how much load it needs to carry, and whether the substrate is solid or hollow. Sleeve anchors expand within the drilled hole to grip solid materials tightly. For cavity walls or plasterboard, different mechanics apply entirely. The plasterboard fixings range covers those hollow wall situations where a standard expansion anchor would fail. For heavy structural applications, anchoring resins provide a chemical bond that outperforms mechanical anchors in crumbling or soft masonry.
Common applications for masonry anchors include:
- Securing frame fixings to concrete lintels or blockwork
- Mounting brackets, rails and structural elements to solid brick
- Fixing into aerated concrete blocks where expansion can cause cracking
- Attaching balustrading, posts or gate hardware to masonry
For jobs that also involve fastening into timber or sheet material, the wood screws range and the broader fixings category at MacBlair cover the full picture. Always match anchor diameter to the drill bit size, clear debris from the hole before fitting, and check the load rating before use on anything structural.
Anchor Fixing FAQ's
For solid concrete, sleeve anchors are one of the most reliable options. You drill a hole to match the anchor diameter, insert the anchor, then tighten the bolt or nut until the sleeve expands and locks against the sides of the hole. For situations where the concrete is older or slightly damaged around the fixing point, a chemical anchor using resin can actually provide a stronger result, as it bonds across the full depth of the hole rather than relying on mechanical expansion alone.
Standard expansion anchors are generally not recommended for aerated concrete blocks such as Thermalite or Celcon. The material is relatively soft and porous, which means expansion forces can cause the block to crack or the anchor to pull out under load. Purpose-made nylon frame anchors or chemical anchoring resins are better suited to this substrate, as they distribute load more evenly without stressing the surrounding material.
Anchor size is determined by two factors: the diameter of the bolt or screw it accommodates, and the minimum embedment depth required for the load. As a general guide, the drill bit diameter should match the anchor body diameter exactly, and the hole depth should be slightly deeper than the anchor length to allow for dust clearance. Always check the manufacturer's load rating for the specific substrate you are fixing into. For heavy or structural fixings, it is worth calculating the shear and tensile loads before selecting an anchor size.
Yes, most sleeve and expansion anchors are rated for use in both solid brick and concrete, though the holding values will typically be lower in brick due to its more variable density. Avoid positioning anchors in the mortar joints between bricks, as these are weaker and the fixing will not hold reliably. If the brickwork is older or the mortar is soft, a chemical anchor or frame anchor with a wider body can spread the load more effectively than a standard expansion type.