Anchoring Base Materials – Concrete, Masonry and Hollow Materials
The base material is one of the most important factors when selecting an anchor. Concrete, masonry, hollow construction materials and lightweight substrates behave differently under load and require anchoring systems that are suitable for their specific properties.
Understanding the strength, structure and condition of the material you are fixing into helps determine which anchor types can be used and how the fixing should be designed and installed.
Why the base material matters
An anchor transfers forces from the attached component into the surrounding base material. The strength and behaviour of that material therefore have a direct influence on the performance of the anchorage.
Important factors can include:
- Type of base material
- Material strength
- Solid or hollow construction
- Concrete strength class
- Cracked or non-cracked concrete
- Thickness of the base material
- Condition and quality of the substrate
- Edge distances and available installation depth
The same anchor can perform very differently when installed in different materials or under different application conditions.
Common anchoring base materials
The categories below provide an overview of some of the most common materials encountered in anchoring applications.
Concrete
Concrete is widely used for structural anchoring and can support a broad range of mechanical and chemical anchoring systems.
Anchor selection depends on factors including concrete strength, cracking, edge distance, spacing and embedment depth.
Solid masonry
Solid brick and other dense masonry materials can provide a suitable base for a range of fixing systems.
Performance depends on the strength and condition of the masonry as well as the anchor type and installation method.
Hollow and lightweight materials
Hollow masonry, lightweight blocks and other low-density materials require particular care because their load-transfer behaviour differs significantly from solid concrete.
Specialised anchors or fixing systems may be required depending on the substrate and application.
Anchoring in concrete
Concrete is one of the most common base materials for structural anchoring. Both mechanical and chemical anchors can be used, provided that the selected system is suitable for the concrete condition and the applicable design requirements.
Concrete strength influences the resistance of the anchorage, while other factors such as cracking, edge distance, anchor spacing and embedment depth can also have a significant effect.
For structural applications, the concrete condition must be considered as part of the anchor design rather than treating all concrete as identical.
Understand cracked and non-cracked concrete >
Cracked and non-cracked concrete
Concrete can develop cracks in areas subjected to tensile stress. These cracks may open and close during the life of the structure and can influence the performance of installed anchors.
Where cracking is expected, the selected anchor must be approved and designed for use in cracked concrete. An anchor suitable only for non-cracked concrete should not automatically be assumed to provide the same performance in cracked concrete.
Learn more about cracked and non-cracked concrete >
Anchoring in solid masonry
Solid masonry can include materials such as solid clay brick, dense concrete block and natural stone. These materials vary considerably in strength and composition, so anchor performance should not be assumed to be the same across all masonry types.
Depending on the application, suitable solutions may include mechanical anchors, plugs, screws or chemical anchoring systems.
Particular attention should be paid to the condition of the masonry, the position of mortar joints, edge distances and the technical approval for the selected fixing.
Anchoring in hollow masonry
Hollow bricks and blocks contain cavities that reduce the amount of solid material available to transfer load. Conventional expansion anchors may therefore behave differently than they would in solid concrete or masonry.
Fixing systems designed specifically for hollow materials can distribute loads more effectively or create a secure connection within the available material.
Chemical anchoring systems used with suitable sleeves may also be appropriate for certain applications, depending on the product approval and substrate.
Anchoring in lightweight materials
Lightweight blocks and aerated materials generally have lower density and strength than standard concrete or dense masonry. This affects the way loads can be transferred into the substrate.
Anchors intended for these materials typically use a larger engagement area or a fixing principle specifically designed for lower-strength substrates.
Always verify that the selected anchor has been tested or approved for the specific base material.
What if the base material is unknown?
If the material cannot be identified with confidence, avoid selecting an anchor based only on appearance. Different blocks and masonry products can look similar while offering very different strengths and internal structures.
Where necessary, identify the construction material from project documentation, product information or suitable site investigation before determining the anchoring solution.
For critical applications, testing on site may also be required where the actual substrate condition cannot be established from documentation alone.
How base material affects anchor failure
Different base materials can result in different potential failure modes. In concrete, resistance may be governed by steel failure, pull-out, concrete cone failure, splitting or concrete edge failure.
In masonry and lightweight materials, failure can also be influenced by the strength and geometry of individual blocks, cavities, mortar joints and local damage around the fixing.
The anchoring system must therefore be assessed as a combination of the anchor and the material into which it is installed.
Learn more about anchor loads and failure modes >
Installation conditions also matter
Even when the correct anchor and base material have been identified, installation conditions can significantly influence performance.
Factors such as drilling method, hole diameter, hole cleaning, installation depth, edge distance, anchor spacing and tightening procedure should follow the relevant product instructions and approval.
Explore anchoring conditions >
Calculate structural anchors in concrete
For structural fastenings in concrete, selecting the correct base material is only one part of the design process. The applied loads, concrete condition, anchor spacing, edge distances, embedment depth and possible failure modes must also be considered.
The Fabory Anchor Calculator helps you design post-installed anchors for structural use in concrete in accordance with EN 1992-4. Enter the concrete and project conditions to identify suitable anchoring solutions and assess the relevant design requirements.
- Design post-installed anchors in accordance with EN 1992-4
- Calculate for different concrete strengths
- Assess cracked and non-cracked concrete
- Consider anchor spacing and edge distances
- Assess fire and seismic design conditions
- Generate calculation reports for project documentation
Use the Fabory Anchor Calculator >
Approvals and technical documentation
Anchor suitability should always be verified against the technical documentation and approval for the selected product.
For structural post-installed anchors in concrete in Europe, product-specific performance and application conditions are typically defined in the relevant European Technical Assessment (ETA), while EN 1992-4 provides the design framework.
For masonry and other substrates, check that the product approval specifically covers the material and installation conditions involved.
Explore more anchoring guidance
Continue exploring Fabory's technical anchoring guidance:
- Types of anchors >
- Understanding anchor loads >
- Cracked and non-cracked concrete >
- Anchoring conditions >
- Practical anchor design >
- Explore all anchoring technical guidance >
Need help selecting an anchor for your base material?
Selecting the right fixing can become more complex when the substrate is unusual, its strength is uncertain or the application involves structural loads. Fabory's technical specialists can help you assess the base material and application requirements and identify suitable anchoring solutions.
Contact our technical specialists >
Frequently asked questions about anchoring base materials
Find answers to common questions about concrete, masonry, hollow materials and selecting anchors for different substrates.
Why does the base material matter when choosing an anchor?
The anchor transfers load into the surrounding base material, so the strength, structure and condition of that material directly influence anchor performance. Different materials may require different anchor types, installation methods and design approaches.
Can the same anchor be used in concrete and masonry?
Not necessarily. An anchor suitable for concrete may not be approved or suitable for masonry. Always check the technical documentation and product approval to confirm which base materials the anchor can be used in.
Can anchors be installed in hollow masonry?
Yes, but the fixing system must be suitable for hollow materials. Depending on the application, this may involve specialised mechanical fixings or chemical anchoring systems used with appropriate sleeves.
How does concrete strength affect anchor performance?
Concrete strength can influence the resistance of an anchorage because the surrounding concrete forms part of the load-transfer system. Anchor performance is also affected by factors including cracking, embedment depth, edge distance and anchor spacing.
Can the Fabory Anchor Calculator account for different concrete conditions?
Yes. The Fabory Anchor Calculator supports different concrete strengths and both cracked and non-cracked concrete when designing post-installed structural anchors in accordance with EN 1992-4.