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