Expansion joint An expansion joint is a gap placed between sections of concrete to allow movement caused by temperature changes or structural expansion. Flexible filler material is typically installed within the joint.
Concrete expands and contracts as temperatures change throughout the year. Expansion joints provide space for this movement, helping reduce pressure that could otherwise damage adjacent slabs or structures. Proper joint placement is an important part of durable sidewalk, driveway, and curb construction.
Frequently Asked Questions About Expansion joint
What is an expansion joint?
A gap between sections of concrete that allows movement from temperature change or structural expansion, usually filled with flexible material.
Why are expansion joints necessary?
Concrete expands in heat and contracts in cold. Without room to move, slabs push against each other and against buildings, causing cracking, spalling and buckling.
Where are they placed?
Typically where a sidewalk meets a building, curb, driveway apron or other fixed structure, and at intervals along long runs.
How is an expansion joint different from a control joint?
An expansion joint is a full-depth gap allowing movement. A control joint is a shallow groove that directs where shrinkage cracking occurs.