Anchor Bolts for Brick or Concrete: What to Check Before Buying
Choose an anchor for the actual material behind the fixing and the connection it needs to make. Concrete, solid brick, perforated brick, hollow block and lightweight block are different substrates. An anchor suitable for one is not automatically suitable for the others.
Before choosing a diameter, identify the wall. Then note what you are attaching, its thickness, the fixing positions and the loads the connection must resist. This is more useful than starting with the largest bolt that will fit through a bracket.
Shield anchor or concrete screw?
| Fixing family | How it holds | Buying check |
|---|---|---|
| Expansion shield anchor | Its shield expands against the sides of the drilled hole | Check the permitted substrate, hole diameter, spacing, edge distance and tightening torque |
| Concrete or masonry screw bolt | Its thread engages with the prepared substrate | Check the exact model’s approved base materials, drill size and embedment |
| Resin anchor system | Resin bonds a specified stud or component into the prepared hole | Check the complete system, substrate, hole preparation and curing conditions |
Names such as “masonry bolt” are used quite broadly. Look at the actual fixing design and technical reference rather than assuming all products under that name install the same way.
Can anchor bolts be used in brick?
Some can, within the manufacturer’s stated conditions. For example, JCP publishes separate solid-brick and concrete information for its loose-bolt shield anchor range. Its solid-brick guidance is not approval for hollow bricks, damaged masonry or an arbitrary mortar joint.
Identify perforations, voids and weak material before buying. Where the substrate or required performance is uncertain, obtain the fixing manufacturer’s recommendation and any necessary site testing. A bigger expansion anchor can still be the wrong choice for the brickwork.
Three sizes that are easy to confuse
Thread size describes the bolt thread. Drill diameter describes the hole required for that anchor. Fixture thickness describes the material held against the substrate. They are not the same measurement.
A shield’s outside diameter can be larger than its bolt thread. With a screw bolt, the stated overall length also does not mean all of that length is embedded: the fixture and any specified washers or stand-off detail occupy part of the connection.
Use the model’s tables for drill size, minimum hole depth, effective or nominal embedment and maximum fixture thickness. Never take those figures from a visually similar anchor.
What a useful product data sheet should tell you
- Which base materials and, where relevant, concrete conditions are covered.
- Hole diameter, depth and cleaning procedure.
- Embedment, edge distances, spacing and minimum substrate thickness.
- Installation torque or setting method.
- Load data and the conditions attached to it.
These conditions work together. A headline load figure is not a capacity for every wall, every fixing position or a group of anchors. Connections for structural loads, overhead items or safety-critical fittings need a suitable design rather than a generic bolt-size rule.
Compare the fixing families
Our loose-bolt shield anchors and hex-head concrete bolts show the different formats. Confirm the exact product and size data before using either. Browse concrete bolts and screws for thread-forming options.
JCP’s technical data library is useful for understanding how fixing specifications are presented. Apply only the sheet for the manufacturer and reference actually supplied.
