Types of Anchors

Anchors are divided into three load groups: light, medium and heavy-duty. Choosing the right anchor depends on the load, the base material and the application environment.

Light anchors — suitable for applications up to 3 kN, including low-load fixing into masonry, plasterboard, hollow walls and aircrete.

Medium anchors — suitable for applications up to 20 kN, typically used in solid masonry and concrete for higher pull-out resistance.

Heavy-duty anchors — suitable for applications up to 60 kN, designed for structural and safety-critical connections in concrete, natural stone and solid masonry.

Below, we explain each group, typical products and how to select the right anchoring solution.

Light Anchors — Up to 3 kN

Light anchors cover all types of plugs used in low-load fastening applications.

They are the most common anchoring products and are used to attach cable ducts, light fixtures, curtain rails and bathroom accessories to walls and ceilings.

Common light anchor types

Universal plugs — suitable for solid and hollow materials

Frame anchors — for fixing door and window frames

Wall plugs — standard nylon plugs for masonry

Aircrete / gas-concrete anchors — designed for aerated concrete blocks

Toggle plugs & molly bolts — for hollow walls, including plasterboard and cavity walls

Hammer-fix plugs — quick installation with a single hammer blow

Self-drilling anchors — no pre-drilling required

Panel anchors & expanding plugs — for thin and panel materials

When to use: mounting cable trays, pipe clips, signage, light shelving and decorative elements where loads remain below 3 kN.

Medium Anchors — Up to 20 kN

Medium anchors are mechanical anchors that expand inside the base material to resist higher pull-out forces.

They are typically used in solid masonry and concrete for applications such as stair rails, handrails, piping brackets and medium equipment mounting.

Common medium anchor types

Wedge bolts — torque-controlled expansion in concrete

Wedge shells — internally threaded inserts for flush-mount applications

Wedge screws — screw-in anchors that combine speed with holding power

When to use: stair rails, pipe supports, cable tray brackets, wall-mounted racking and equipment bases for loads of 3–20 kN.

Heavy-Duty Anchors — Up to 60 kN

Heavy-duty anchors are designed for structural and safety-critical connections in concrete, natural stone and solid masonry.

Any application in the tension zone of a concrete element always requires a heavy-duty anchor, regardless of the actual load.

Common heavy-duty anchor types

Safety bolts — approved for cracked and uncracked concrete

Wedge anchors — high-load torque-controlled expansion

Undercut anchors — mechanical interlock for maximum pull-out resistance

Chemical anchors — resin systems using injectable mortar for maximum flexibility and load transfer

Hammer-set anchors — fast installation in uncracked concrete

Cast-in anchors — masonry bolts, hook anchors and tube inserts placed before or during concrete pouring

When to use: steel construction connections, façade systems, heavy machinery bases, safety barriers, structural beams and any application in the tension zone of concrete.

Anchor Load Categories

A simple overview of typical anchor categories, suitable base materials, common products and application examples.

How to Choose the Right Anchor

Selecting the correct anchor requires four key considerations.

Load calculation

Determine the static and dynamic loads, including tension, shear or combined loads. Always use a safety factor in accordance with applicable building codes.

Base material

Identify whether the substrate is solid concrete, hollow masonry, aerated concrete, plasterboard or natural stone. Each material limits which anchor types can be used.

Cracked or uncracked concrete

Applications in cracked concrete or the tension zone require anchors with specific approvals, such as ETA or equivalent approvals.

Installation environment

Consider temperature, humidity, vibration and chemical exposure. Stainless steel A4 anchors are recommended for outdoor, wet or corrosive environments.

Tip: When in doubt, use the higher load category. An over-specified anchor adds minimal cost but significantly increases the safety margin.

Standards & Approvals

Anchor performance and safety are governed by international standards and approval bodies.

EOTA / EAD — European Organisation for Technical Assessment. Issues European Technical Assessments, known as ETAs, for construction anchors. The key guideline is EAD 330232, formerly ETAG 001.

EN 1992-4 — Eurocode 2, Part 4: design of fastenings in concrete. Replaced the previous CEN/TS 1992-4 series.

ACI 318 Appendix D / ACI 355 — American Concrete Institute standards for anchor design and qualification testing.

ASTM E488 / E1512 — American Society for Testing and Materials test methods for anchors in concrete and masonry.

ICC-ES — International Code Council Evaluation Service, successor to ICBO ES. Issues evaluation reports for North American building codes.

The European EOTA and American ACI calculation methods largely align, enabling economical and efficient anchor design across international projects.

Frequently Asked Questions

Common questions about anchor selection, base materials and installation conditions.

What is the difference between a mechanical anchor and a chemical anchor?

A mechanical anchor expands inside the drill hole using friction or mechanical interlock, such as a wedge or undercut system. A chemical anchor uses an injectable resin or mortar to bond a threaded rod to the base material. Chemical anchors offer more flexibility in edge distances and spacing, and they transfer load over a larger area, making them ideal for close-to-edge and group installations.

Can I use standard plugs in aerated concrete?

No. Standard nylon plugs are designed for solid masonry. Aerated concrete, also known as aircrete, has lower density and compressive strength, so you need special aircrete anchors with wider expansion wings or a spiral design that grips the soft material without cracking it.

When must I use a heavy-duty anchor even for light loads?

Always when the anchor point is in the tension zone of a concrete element. Concrete in the tension zone is assumed to be cracked, which can significantly reduce the pull-out capacity of light and medium anchors. Heavy-duty anchors with cracked-concrete approvals, such as ETA-approved anchors, are required in this situation.

How do I know if concrete is cracked or uncracked?

As a rule, the tension zone, such as the lower part of a beam or the area around openings, is assumed to be cracked. The compression zone, such as the upper part of a simply supported beam or columns under axial load, may be considered uncracked. When in doubt, always design for cracked concrete, as this is the safer assumption.

What material should anchors be in wet or corrosive environments?

Use stainless steel A4, also known as AISI 316, anchors for outdoor, coastal, wet or chemically aggressive environments. Standard zinc-plated carbon steel anchors are suitable for dry indoor applications. For extremely corrosive environments, such as swimming pools or chemical plants, consider A5, duplex stainless steel or coated special alloys.

Related Anchoring Products

Explore Fabory’s anchoring range:

Anchoring products — Full range of light, medium and heavy-duty anchors

Bolts — Anchor bolts, threaded rods and stud bolts

Nuts — Hex nuts, coupling nuts and anchor plate nuts

Washers and Rings — Flat washers and base plates for anchor installations

Chemical anchors & resins — Injectable mortars and capsule anchors

Need help selecting the right anchoring system?

Contact our technical team

Last updated: July 2026