Definition: Expansion Joints

The Hunter Inspector

Definition: Expansion Joints

definitionsexpansion joints
Updated: December 3, 2019

Definition

An expansion joint is a thin gap built into brickwork which allows for slight movement which may naturally occur (from seasonal heat changes or foundation settlement etc.).

There are a couple of sub categories of Expansion joints including control joints, and articulation joints. Each a slightly more specific definition, but generally follow the same principle of allowing small amounts of movement in materials.

Materials

Expansion joints in Australian residential buildings are typically filled with a pre-moulded foam strip or neoprene pad. A Licensed builder who takes pride in his work will typically try to colour match the expansion joint with the brickwork. It is important that the material used in the expansion joint is weatherproof; most expansion joints will require a special flexible sealant for adequate weather proofing.

Purpose

The purpose of an expansion joint is to allow for small amounts of expansion and contraction to avoid cracking or more significant damage to brick walls or concrete slabs.

Expansion Joint Defects

Some of the more common defects we find during building and pest inspections, relating to expansion joints include:

  • Expansion joints missing entirely.
  • Expansion joints which have been placed, but in the wrong positions can still allow cracking to occur.
  • Expansion joints which are missing the expansion foam filler and not sealed. This will allow moisture penetration straight into the brickwork.