Expansion Anchor

Back to Glossary

Expansion Anchor

What is Expansion Anchor?

An expansion anchor is a mechanical fastener that expands inside concrete or masonry to provide secure load-bearing attachment.

Description

An expansion anchor is a type of mechanical fastener designed to secure objects to concrete, masonry, or solid substrates by expanding against the walls of a drilled hole. When tightened, the anchor creates outward pressure that locks it firmly in place.

In construction, expansion anchors are commonly used to attach structural steel, equipment, handrails, shelving, and fixtures to concrete slabs or walls. Common types include wedge anchors, sleeve anchors, drop-in anchors, and shield anchors, each suited to specific load requirements and installation conditions.

Proper selection and installation are critical for expansion anchor performance. Factors such as base material strength, embedment depth, edge distance, and load type must be considered. When installed according to manufacturer specifications and building codes, expansion anchors provide reliable holding strength for both structural and non-structural applications.

FAQs

  • What is an expansion anchor used for?

    It is used to fasten objects securely into concrete or masonry substrates.

  • How does an expansion anchor work?

    It expands inside a drilled hole when tightened, creating friction and mechanical lock.

  • What materials can expansion anchors be installed into?

    They are typically installed into concrete, brick, or solid masonry.

  • Are expansion anchors load-rated?

    Yes, anchors are rated for specific tension and shear loads based on size and material.

  • Can expansion anchors be removed?

    Some types can be removed, while others are intended for permanent installation.

Fun Fact

Wedge-style expansion anchors actually increase their holding power as loads are applied—up to their rated capacity.

CSI Code

05 05 23

NAHB Code

550